- ID:
- ivo://CDS.VizieR/J/AN/326/321
- Title:
- Absolute magnitudes for late-type dwarfs
- Short Name:
- J/AN/326/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new formula for absolute magnitude determination for late-type dwarf stars as a function of (g-r) and (r-i) for Sloan photometry (as defined by Abazajian et al., 2003AJ....126.2081A). The absolute magnitudes estimated by this approach are brighter than those estimated by colour-magnitude diagrams, and they reduce the luminosity function rather close to the luminosity function of Hipparcos.
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- ID:
- ivo://CDS.VizieR/J/AJ/144/95
- Title:
- Abundance in stars of the outer galactic disk. IV.
- Short Name:
- J/AJ/144/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocities and chemical abundances for nine stars in the old, distant open clusters Be18, Be21, Be22, Be32, and PWM4. For Be18 and PWM4, these are the first chemical abundance measurements. Combining our data with literature results produces a compilation of some 68 chemical abundance measurements in 49 unique clusters. For this combined sample, we study the chemical abundances of open clusters as a function of distance, age, and metallicity. We confirm that the metallicity gradient in the outer disk is flatter than the gradient in the vicinity of the solar neighborhood. We also confirm that the open clusters in the outer disk are metal-poor with enhancements in the ratios [{alpha}/Fe] and perhaps [Eu/Fe]. All elements show negligible or small trends between [X/Fe] and distance (<0.02dex/kpc), but for some elements, there is a hint that the local (R_GC_<13kpc) and distant (R_GC_>13kpc) samples may have different trends with distance. There is no evidence for significant abundance trends versus age (<0.04dex/Gyr). We measure the linear relation between [X/Fe] and metallicity, [Fe/H], and find that the scatter about the mean trend is comparable to the measurement uncertainties. Comparison with solar neighborhood field giants shows that the open clusters share similar abundance ratios [X/Fe] at a given metallicity. While the flattening of the metallicity gradient and enhanced [{alpha}/Fe] ratios in the outer disk suggest a chemical enrichment history different from that of the solar neighborhood, we echo the sentiments expressed by Friel et al. that definitive conclusions await homogeneous analyses of larger samples of stars in larger numbers of clusters. Arguably, our understanding of the evolution of the outer disk from open clusters is currently limited by systematic abundance differences between various studies.
- ID:
- ivo://CDS.VizieR/J/ApJ/682/1217
- Title:
- Abundances in red giants in 7 globular clusters
- Short Name:
- J/ApJ/682/1217
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a technique that applies spectral synthesis to medium-resolution spectroscopy (MRS; R~6000) in the red (6300{AA}<{lambda}<9100{AA}) to measure [Fe/H] and [{alpha}/Fe] of individual red giant stars over a wide metallicity range. We apply our technique to 264 red giant stars in seven Galactic globular clusters and demonstrate that it reproduces the metallicities and {alpha}-enhancements derived from high-resolution spectroscopy (HRS). The MRS technique excludes the three CaII triplet lines and instead relies on a plethora of weaker lines. Unlike empirical metallicity estimators, such as the equivalent width of the CaII triplet, the synthetic method presented here is applicable over an arbitrarily wide metallicity range and is independent of assumptions about the {alpha}-enhancement.
- ID:
- ivo://CDS.VizieR/J/ApJS/191/352
- Title:
- Abundances in stars of Milky Way dwarf satellites
- Short Name:
- J/ApJS/191/352
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of Fe, Mg, Si, Ca, and Ti abundances for 2961 stars in eight dwarf satellite galaxies of the Milky Way (MW): Sculptor, Fornax, Leo I, Sextans, Leo II, Canes Venatici I, Ursa Minor, and Draco. For the purposes of validating our measurements, we also observed 445 red giants in MW globular clusters and 21 field red giants in the MW halo. The measurements are based on Keck/DEIMOS medium-resolution spectroscopy (MRS) combined with spectral synthesis. We estimate uncertainties in [Fe/H] by quantifying the dispersion of [Fe/H] measurements in a sample of stars in monometallic globular clusters (GCs). We estimate uncertainties in Mg, Si, Ca, and Ti abundances by comparing to high-resolution spectroscopic abundances of the same stars. For this purpose, a sample of 132 stars with published high-resolution spectroscopy in GCs, the MW halo field, and dwarf galaxies has been observed with MRS. The standard deviations of the differences in [Fe/H] and <[{alpha}/Fe]> (the average of [Mg/Fe], [Si/Fe], [Ca/Fe], and [Ti/Fe]) between the two samples is 0.15 and 0.16, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A100
- Title:
- Abundances red giants in Carina dSph
- Short Name:
- J/A+A/538/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ages of individual Red Giant Branch stars can range from 1Gyr old to the age of the Universe, and it is believed that the abundances of most chemical elements in their photospheres remain unchanged with time (those that are not affected by the first dredge-up). This means that they trace the interstellar medium in the galaxy at the time the star formed, and hence the chemical enrichment history of the galaxy. Colour-Magnitude Diagram analysis has shown the Carina dwarf spheroidal to have had an unusually episodic star formation history and this is expected to be reflected in the abundances of different chemical elements.
- ID:
- ivo://CDS.VizieR/J/AJ/155/180
- Title:
- A catalog of cool dwarf targets for the TESS
- Short Name:
- J/AJ/155/180
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of cool dwarf targets (V-J>2.7, T_eff_~<4000 K) and their stellar properties for the upcoming Transiting Exoplanet Survey Satellite (TESS), for the purpose of determining which cool dwarfs should be observed using two minute observations. TESS has the opportunity to search tens of thousands of nearby, cool, late K- and M-type dwarfs for transiting exoplanets, an order of magnitude more than current or previous transiting exoplanet surveys, such as Kepler, K2, and ground-based programs. This necessitates a new approach to choosing cool dwarf targets. Cool dwarfs are chosen by collating parallax and proper motion catalogs from the literature and subjecting them to a variety of selection criteria. We calculate stellar parameters and TESS magnitudes using the best possible relations from the literature while maintaining uniformity of methods for the sake of reproducibility. We estimate the expected planet yield from TESS observations using statistical results from the Kepler mission, and use these results to choose the best targets for two minute observations, optimizing for small planets for which masses can conceivably be measured using follow-up Doppler spectroscopy by current and future Doppler spectrometers. The catalog is available in machine readable format and is incorporated into the TESS Input Catalog and TESS Candidate Target List until a more complete and accurate cool dwarf catalog identified by ESA's Gaia mission can be incorporated.
- ID:
- ivo://CDS.VizieR/J/ApJS/245/10
- Title:
- A catalog of galaxies in direction of Perseus
- Short Name:
- J/ApJS/245/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 5437 morphologically classified sources in the direction of the Perseus galaxy cluster core, among them 496 early-type low-mass galaxy candidates. The catalog is primarily based on V-band imaging data acquired with the William Herschel Telescope, which we used to conduct automated source detection and derive photometry. We additionally reduced archival Subaru multiband imaging data in order to measure aperture colors and perform a morphological classification, benefiting from 0.5" seeing conditions in the r-band data. Based on morphological and color properties, we extracted a sample of early-type low-mass galaxy candidates with absolute V-band magnitudes in the range of -10 to -20mag. In the color-magnitude diagram, the galaxies are located where the red sequence for early-type cluster galaxies is expected, and they lie on the literature relation between absolute magnitude and Sersic index. We classified the early-type dwarf candidates into nucleated and nonnucleated galaxies. For the faint candidates, we found a trend of increasing nucleation fraction toward brighter luminosity or higher surface brightness, similar to what is observed in other nearby galaxy clusters. We morphologically classified the remaining sources as likely background elliptical galaxies, late-type galaxies, edge-on disk galaxies, and likely merging systems and discussed the expected contamination fraction through non-early-type cluster galaxies in the magnitude-size surface brightness parameter space. Our catalog reaches its 50% completeness limit at an absolute V-band luminosity of -12mag and a V-band surface brightness of 26mag/arcsec^2^. This makes it the largest and deepest catalog with coherent coverage compared to previous imaging studies of the Perseus cluster.
- ID:
- ivo://CDS.VizieR/J/MNRAS/412/127
- Title:
- ACCESS. II. Shapley galaxies FUV-FIR photometry
- Short Name:
- J/MNRAS/412/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present panoramic Spitzer/MIPS mid- and far-infrared (MIR/FIR) and GALEX ultraviolet imaging of the most massive and dynamically active system in the local Universe, the Shapley supercluster at z=0.048, covering the five clusters that make up the supercluster core. We combine these data with existing spectroscopic data from 814 confirmed supercluster members to produce the first study of a local rich cluster including both ultraviolet and infrared luminosity functions (LFs).
- ID:
- ivo://CDS.VizieR/J/ApJ/710/597
- Title:
- Accretion in disks in Cep OB2
- Short Name:
- J/ApJ/710/597
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present accretion rates for a large number of solar-type stars in the Cep OB2 region, based on U-band observations. Our study comprises 95 members of the ~4Myr old cluster Tr 37 (including 20 "transition" objects (TOs)), as well as the only classical T Tauri star (CTTS) in the ~12Myr old cluster NGC 7160. The stars show different disk morphologies, with the majority of them having evolved and flattened disks. The typical accretion rates are about 1 order of magnitude lower than in regions aged 1-2Myr, and we find no strong correlation between disk morphology and accretion rates. Although half of the TOs are not accreting, the median accretion rates of normal CTTS and accreting "transition" disks are similar (~3x10^-9^ and 2x10^-9^M_{sun}_/yr, respectively). Comparison with other regions suggests that the TOs observed at different ages do not necessarily represent the same type of objects, which is consistent with the fact that the different processes that can lead to reduced IR excess/inner disk clearing (e.g., binarity, dust coagulation/settling, photoevaporation, giant planet formation) do not operate on the same timescales.
- ID:
- ivo://CDS.VizieR/J/ApJS/220/10
- Title:
- AEGIS-X Deep survey of EGS (AEGIS-XD)
- Short Name:
- J/ApJS/220/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of deep Chandra imaging of the central region of the Extended Groth Strip, the AEGIS-X Deep (AEGIS-XD) survey. When combined with previous Chandra observations of a wider area of the strip, AEGIS-X Wide (AEGIS-XW), these provide data to a nominal exposure depth of 800ks in the three central ACIS-I fields, a region of approximately 0.29deg^2^. This is currently the third deepest X-ray survey in existence; a factor ~2-3 shallower than the Chandra Deep Fields (CDFs), but over an area ~3 times greater than each CDF. We present a catalog of 937 point sources detected in the deep Chandra observations, along with identifications of our X-ray sources from deep ground-based, Spitzer, GALEX, and Hubble Space Telescope imaging. Using a likelihood ratio analysis, we associate multiband counterparts for 929/937 of our X-ray sources, with an estimated 95% reliability, making the identification completeness approximately 94% in a statistical sense. Reliable spectroscopic redshifts for 353 of our X-ray sources are available predominantly from Keck (DEEP2/3) and MMT Hectospec, so the current spectroscopic completeness is ~38%. For the remainder of the X-ray sources, we compute photometric redshifts based on multiband photometry in up to 35 bands from the UV to mid-IR. Particular attention is given to the fact that the vast majority the X-ray sources are active galactic nuclei and require hybrid templates. Our photometric redshifts have mean accuracy of {sigma}=0.04 and an outlier fraction of approximately 5%, reaching {sigma}=0.03 with less than 4% outliers in the area covered by CANDELS.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/862
- Title:
- Afterglow light curve of GRB 090926A
- Short Name:
- J/ApJ/720/862
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VLT/FORS2 spectroscopy and Gamma-ray Optical/Near-Infrared Detector optical/near-IR photometry of the afterglow of the bright Fermi/LAT GRB 090926A. The spectrum shows prominent Lyman-{alpha} absorption with N_HI_=10^21.73+/-0.07^cm^-2^ and a multitude of metal lines at a common redshift of z=2.1062+/-0.0004, which we associate with the redshift of the gamma-ray burst (GRB). The metallicity derived from SII is log(Z/Z_{sun}_)~-1.9, one of the lowest values ever found in a GRB Damped Lyman-{alpha} (DLA) system. This confirms that the spread of metallicity in GRB-DLAs at z~2 is at least two orders of magnitude. We argue that this spread in metallicity does not require a similar range in abundances of the GRB progenitors, since the neutral interstellar medium probed by the DLA is expected to be at a significant distance from the explosion site. The hydrogen column density derived from the Swift/XRT afterglow spectrum (assuming log(Z/Z_{sun}_)~-1.9) is ~100 times higher than the N_HI_ obtained from the Lyman-{alpha} absorptions. This suggests either a large column density of ionized gas or a higher metallicity of the circum-burst medium compared to the gas traced by the DLA. We also discuss the afterglow light curve evolution and energetics. The absence of a clear jet-break like steeping until at least 21 days post-burst suggests a beaming-corrected energy release of E_{gamma}_>3.5x10^52^erg, indicating that GRB 090926A may have been one of the most energetic bursts ever detected.
- ID:
- ivo://CDS.VizieR/J/MNRAS/475/257
- Title:
- AGB subpopulations in NGC 6397
- Short Name:
- J/MNRAS/475/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has been well established that Galactic Globular clusters (GCs) harbour more than one stellar population, distinguishable by the anticorrelations of light-element abundances (C-N, Na-O, and Mg-Al). These studies have been extended recently to the asymptotic giant branch (AGB). Here, we investigate the AGB of NGC 6397 for the first time. We have performed an abundance analysis of high-resolution spectra of 47 red giant branch (RGB) and eight AGB stars, deriving Fe, Na, O, Mg, and Al abundances. We find that NGC 6397 shows no evidence of a deficit in Na-rich AGB stars, as reported for some other GCs - the subpopulation ratios of the AGB and RGB in NGC 6397 are identical, within uncertainties. This agrees with expectations from stellar theory. This GC acts as a control for our earlier work on the AGB of M4 (with contrasting results), since the same tools and methods were used.
- ID:
- ivo://CDS.VizieR/J/ApJ/751/122
- Title:
- Ages and masses for 920 LMC clusters
- Short Name:
- J/ApJ/751/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new age and mass estimates for 920 stellar clusters in the Large Magellanic Cloud (LMC) based on previously published broadband photometry and the stellar cluster analysis package, MASSCLEANage. Expressed in the generic fitting formula, d^2^N/dMdt{prop.to}M^{alpha}^t^{beta}^, the distribution of observed clusters is described by {alpha}=-1.5 to -1.6 and {beta}=-2.1 to -2.2. For 288 of these clusters, ages have recently been determined based on stellar photometric color-magnitude diagrams, allowing us to gauge the confidence of our ages. The results look very promising, opening up the possibility that this sample of 920 clusters, with reliable and consistent age, mass, and photometric measures, might be used to constrain important characteristics about the stellar cluster population in the LMC. We also investigate a traditional age determination method that uses a {chi}^2^ minimization routine to fit observed cluster colors to standard infinite-mass limit simple stellar population models. This reveals serious defects in the derived cluster age distribution using this method. The traditional {chi}^2^ minimization method, due to the variation of U, B, V, R colors, will always produce an overdensity of younger and older clusters, with an underdensity of clusters in the log(age/yr)=[7.0,7.5] range. Finally, we present a unique simulation aimed at illustrating and constraining the fading limit in observed cluster distributions that includes the complex effects of stochastic variations in the observed properties of stellar clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/870/9
- Title:
- Ages & masses for GPS1 WD-MS binary systems
- Short Name:
- J/ApJ/870/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observational tests of stellar and Galactic chemical evolution call for the joint knowledge of a star's physical parameters, detailed element abundances, and precise age. For cool main-sequence (MS) stars the abundances of many elements can be measured from spectroscopy, but ages are very hard to determine. The situation is different if the MS star has a white dwarf (WD) companion and a known distance, as the age of such a binary system can then be determined precisely from the photometric properties of the cooling WD. As a pilot study for obtaining precise age determinations of field MS stars, we identify nearly 100 candidates for such wide binary systems: a faint WD whose Gaia-PS1-SDSS (GPS1) proper motion (Tian+ 2017, I/343) matches that of a brighter MS star in Gaia/TGAS (Gaia Collaboration 2016, I/337) with a good parallax ({sigma}_{rho}_/{rho}=<0.05). We model the WD's multi-band photometry with the BASE-9 code using this precise distance (assumed to be common for the pair) and infer ages for each binary system. The resulting age estimates are precise to =<10% (=<20%) for 42 (67) MS-WD systems. Our analysis more than doubles the number of MS-WD systems with precise distances known to date, and it boosts the number of such systems with precise age determination by an order of magnitude. With the advent of the Gaia DR2 (Gaia Collaboration, 2018, I/345) data, this approach will be applicable to a far larger sample, providing ages for many MS stars (that can yield detailed abundances for over 20 elements), especially in the age range of 2-8Gyr, where there are only few known star clusters.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/58
- Title:
- Ages of field stars from white dwarf comp. in Gaia
- Short Name:
- J/ApJS/253/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze 4050 wide binary star systems involving a white dwarf (WD) and usually a main-sequence (MS) star, drawn from the large sample assembled by Tian+ (2020, J/ApJS/246/4). Using the modeling code BASE-9, we determine the system's ages, the WD progenitors' zero-age MS masses, the extinction values (AV), and the distance moduli. Discarding the cases with poor age convergences, we obtain ages for 3551 WDs, with a median age precision of {sigma}{tau}/{tau}=20%, and system ages typically in the range of 1-6Gyr. We validated these ages against the very few known clusters and through cross validation of 236 WD-WD binaries. Under the assumption that the components are coeval in a binary system, this provides precise age constraints on the usually low-mass MS companions, mostly inaccessible by any other means.
- ID:
- ivo://CDS.VizieR/J/AJ/146/87
- Title:
- AGN photometry. II. A catalog from the CFHTLS
- Short Name:
- J/AJ/146/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second paper of the series Detecting Active Galactic Nuclei Using Multi-filter Imaging Data. In this paper we review shapelets, an image manipulation algorithm, which we employ to adjust the point-spread function (PSF) of galaxy images. This technique is used to ensure the image in each filter has the same and sharpest PSF, which is the preferred condition for detecting AGNs using multi-filter imaging data as we demonstrated in Paper I of this series. We apply shapelets on Canada-France-Hawaii Telescope Legacy Survey Wide Survey ugriz images. Photometric parameters such as effective radii, integrated fluxes within certain radii, and color gradients are measured on the shapelets-reconstructed images. These parameters are used by artificial neural networks (ANNs) which yield: photometric redshift with an rms of 0.026 and a regression R-value of 0.92; galaxy morphological types with an uncertainty less than 2 T types for z<=0.1; and identification of galaxies as AGNs with 70% confidence, star-forming/starburst (SF/SB) galaxies with 90% confidence, and passive galaxies with 70% confidence for z<=0.1. The incorporation of ANNs provides a more reliable technique for identifying AGN or SF/SB candidates, which could be very useful for large-scale multi-filter optical surveys that also include a modest set of spectroscopic data sufficient to train neural networks.
- ID:
- ivo://CDS.VizieR/J/A+A/601/A10
- Title:
- A grid of MARCS model atmospheres for S stars
- Short Name:
- J/A+A/601/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- S-type stars are late-type giants whose atmospheres are enriched in carbon and s-process elements because of either extrinsic pollution by a binary companion or intrinsic nucleosynthesis and dredge-up on the thermally-pulsing asymptotic giant branch. A grid of MARCS model atmospheres has been computed for S stars, covering the range 2700<=Teff(K)<=4000, 0.50<=C/O<0.99, 0<=logg<=5, [Fe/H]=0., -0.5dex, and [s/Fe]= 0, 1, and 2 dex (where the latter quantity refers to the global overabundance of s-process elements). The MARCS models make use of a new ZrO line list. Synthetic spectra computed from these models are used to derive photometric indices in the Johnson and Geneva systems, as well as TiO and ZrO band strengths. A method is proposed to select the model best matching any given S star, a non-trivial operation since the grid contains more than 3500 models covering a five-dimensional parameter space. The method is based on the comparison between observed and synthetic photometric indices and spectral band strengths, and has been applied on a vast subsample of the Henize sample of S stars. Our results confirm the old claim by Piccirillo (1980MNRAS.190..441P) that ZrO bands in warm S stars (Teff > 3200K) are not caused by the C/O ratio being close to unity, as traditionally believed, but rather by some Zr overabundance. The TiO and ZrO band strengths, combined with V-K and J-K photometric indices, are used to select Teff, C/O, [Fe/H] and [s/Fe]. The Geneva U-B_1 and B_2-V_1 indices (or any equivalent) are good at selecting the gravity. The defining spectral features of dwarf S stars are outlined, but none is found among the Henize S stars. More generally, it is found that, at Teff=3200K, a change of C/O from 0.5 to 0.99 has a strong impact on V-K (2mag). Conversely, a range of 2 mag in V-K corresponds to a 200K shift along the (Teff, V-K) relationship (for a fixed C/O value). Hence, the use of a (Teff, V-K) calibration established for M stars will yield large errors for S stars, so that a specific calibration must be used, as provided in the present paper. Using the atmospheric parameters derived by our method for the sample of Henize S stars, we show that the extrinsic-intrinsic dichotomy among S stars reveals itself very clearly as a bimodal distribution in the effective temperatures. Moreover, the increase of s-process element abundances with increasing C/O ratios and decreasing temperatures is apparent among intrinsic stars, confirming theoretical expectations.
- ID:
- ivo://CDS.VizieR/J/ApJS/183/295
- Title:
- A K-selected catalog of the ECDFS from MUSYC
- Short Name:
- J/ApJS/183/295
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new, K-selected, optical-to-near infrared photometric catalog of the Extended Chandra Deep Field South (ECDFS), making it publicly available to the astronomical community. The data set is founded on publicly available imaging, supplemented by original z'JK imaging data collected as part of the MUltiwavelength Survey by Yale-Chile (MUSYC). The final photometric catalog consists of photometry derived from UU_38_BVRIz'JK imaging covering the full 1/2x1/2{deg} of the ECDFS, plus H-band photometry for approximately 80% of the field. The 5{sigma} flux limit for point sources is K^(AB)^_tot_=22.0. This is also the nominal completeness and reliability limit of the catalog: the empirical completeness for 21.75<K<22.00 is >~85%. We have verified the quality of the catalog through both internal consistency checks, and comparisons to other existing and publicly available catalogs. As well as the photometric catalog, we also present catalogs of photometric redshifts and rest-frame photometry derived from the 10-band photometry. We have collected robust spectroscopic redshift determinations from published sources for 1966 galaxies in the catalog. Based on these sources, we have achieved a (1{sigma}) photometric redshift accuracy of {Delta}z/(1+z)=0.036, with an outlier fraction of 7.8%. Most of these outliers are X-ray sources. Finally, we describe and release a utility for interpolating rest-frame photometry from observed spectral energy distributions, dubbed InterRest available via http://www.strw.leidenuniv.nl/~ent/InterRest
- ID:
- ivo://CDS.VizieR/J/AJ/145/149
- Title:
- ALFALFA discovery of Leo P. II. BVR photometry
- Short Name:
- J/AJ/145/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from ground-based optical imaging of a low-mass dwarf galaxy discovered by the ALFALFA 21cm HI survey. Broadband (BVR) data obtained with the WIYN 3.5m telescope at Kitt Peak National Observatory (KPNO) are used to construct color-magnitude diagrams of the galaxy's stellar population down to V_o_~25. We also use narrowband H{alpha} imaging from the KPNO 2.1m telescope to identify a HII region in the galaxy. We use these data to constrain the distance to the galaxy to be between 1.5 and 2.0Mpc. This places Leo P within the Local Volume but beyond the Local Group. Its properties are extreme: it is the lowest-mass system known that contains significant amounts of gas and is currently forming stars.
- ID:
- ivo://CDS.VizieR/J/AJ/147/145
- Title:
- Algol-type binaries. VIII. DI Peg & AF Gem
- Short Name:
- J/AJ/147/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New extensive photometry for two triple binary stars, DI Peg and AF Gem, was performed from 2012 October to 2013 January, with two small telescopes at Xinglong station (XLs) of NAOC. From new multi-color observations and previously published ones in literature, the photometric models were (re)deduced using the updated Wilson-Devinney code. The results indicated that the low third lights exist in two classic Algol-type binaries, whose fill-out factors for the more massive components are f_p_=78.2(+/-0.4)% for DI Peg, and f_p_=69.0(+/-0.3)% for AF Gem, respectively. Through analyzing the O-C curves, the orbital periods for two binaries change in the complicated mode. The period of DI Peg possibly appears to show two light-time orbits, whose modulated periods are P_3_=54.6(+/-0.5)yr and P_4_=23.0(+/-0.6)yr, respectively. The inferred minimum masses for the inner and outer sub-stellar companions are M_in_=0.095M_{sun}_ and M_out_=0.170M_{sun}_, respectively. Therefore, DI Peg may be a quadruple star. The orbital period of AF Gem appears to show a continuous period decrease or a cyclic variation; the latter may be preferable. The cyclic oscillation, with a period of 120.3(+/-2.5)yr, may be attributed to the light-time effect due to the third body. This kind of additional companion may extract angular momentum from the central system, which may play a key role in the evolution of the binary.
- ID:
- ivo://CDS.VizieR/J/ApJ/742/112
- Title:
- All quiescent magnitudes for CI Aql and U Sco
- Short Name:
- J/ApJ/742/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I report on the cumulative results from a program started 24 years ago designed to measure the orbital period change of recurrent novae (RNe) across an eruption. The goal is to use the orbital period change to measure the mass ejected during each eruption as the key part of trying to measure whether the RNe white dwarfs are gaining or losing mass over an entire eruption cycle, and hence whether they can be progenitors for Type Ia supernovae. This program has now been completed for two eclipsing RNe: CI Aquilae (CI Aql) across its eruption in 2000 and U Scorpii (U Sco) across its eruption in 1999. For CI Aql, I present 78 eclipse times from 1991 to 2009 (including four during the tail of the 2000 eruption) plus two eclipses from 1926 and 1935. For U Sco, I present 67 eclipse times, including 46 times during quiescence from 1989 to 2009, plus 21 eclipse times in the tails of the 1945, 1999, and 2010 eruptions. The eclipse times during the tails of eruptions are systematically and substantially shifted with respect to the ephemerides from the eclipses in quiescence, with this being caused by shifts of the center of light during the eruption. These eclipse times are plotted on an O-C diagram and fitted to models with a steady period change (dP/dt) between eruptions (caused by, for example, conservative mass transfer) plus an abrupt period change ({Delta}P) at the time of eruption. The primary uncertainty arises from the correlation between {Delta}P with dP/dt, such that a more negative dP/dt makes for a more positive {Delta}P. For CI Aql, the best fit is {Delta}P=-3.7^+9.2^_-7.3_x10^-7^. For U Sco, the best fit is {Delta}P=(+43+/-69)x10^-7^ days. These period changes can directly give a dynamical measure of the mass ejected (M_ejecta_) during each eruption with negligible sensitivity to the stellar masses and no uncertainty from distances. For CI Aql, the 1{sigma} upper limit is M_ejecta_<10x10^-7^ M_{sun}_. For U Sco, I derive M_ejecta_=(43+/-67)x10^-7^ M_{sun}_.
- ID:
- ivo://CDS.VizieR/VI/135
- Title:
- All-sky spectrally matched Tycho2 stars
- Short Name:
- VI/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present fitted UBVRI-ZY and u'g'r'i'z' magnitudes, spectral types, and distances for 2.4 million stars, derived from synthetic photometry of a library spectrum that best matches the Tycho2 BTVT, NOMAD RN, and 2MASS JHK2/S catalog magnitudes. We present similarly synthesized multifilter magnitudes, types, and distances for 4.8 million stars with 2MASS and SDSS photometry to g<16 within the Sloan survey region, for Landolt and Sloan primary standards, and for Sloan northern (photometric telescope) and southern secondary standards.
- ID:
- ivo://CDS.VizieR/J/A+A/504/959
- Title:
- Amplitudes of single-mode Cepheids
- Short Name:
- J/A+A/504/959
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The dependence of amplitude on the pulsation period differs from other Cepheid-related relationships. We attempt to revise the period-amplitude (P-A) relationship of Galactic Cepheids based on multi-colour photometric and radial velocity data. Reliable P-A graphs for Galactic Cepheids constructed for the U, B, V, Rc, and Ic photometric bands and pulsational radial velocity variations facilitate investigations of previously poorly studied interrelations between observable amplitudes. The effects of both binarity and metallicity on the observed amplitude, and the dichotomy between short- and long-period Cepheids can both be studied. A homogeneous data set was created that contains basic physical and phenomenological properties of 369 Galactic Cepheids. Pulsation periods were revised and amplitudes were determined by the Fourier method. P-A graphs were constructed and an upper envelope to the data points was determined in each graph. Correlations between various amplitudes and amplitude-related parameters were searched for, using Cepheids without known companions.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/125
- Title:
- An ALMA survey of ECDFS submillimeter galaxies
- Short Name:
- J/ApJ/788/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first photometric redshift distribution for a large sample of 870 {mu}m submillimeter galaxies (SMGs) with robust identifications based on observations with ALMA. In our analysis we consider 96 SMGs in the Extended Chandra Deep Field South, 77 of which have 4-19 band photometry. We model the SEDs for these 77 SMGs, deriving a median photometric redshift of z_phot_=2.3+/-0.1. The remaining 19 SMGs have insufficient photometry to derive photometric redshifts, but a stacking analysis of Herschel observations confirms they are not spurious. Assuming that these SMGs have an absolute H-band magnitude distribution comparable to that of a complete sample of z~1-2 SMGs, we demonstrate that they lie at slightly higher redshifts, raising the median redshift for SMGs to z_phot_=2.5+/-0.2. Critically we show that the proportion of galaxies undergoing an SMG-like phase at z>=3 is at most 35%+/-5% of the total population. We derive a median stellar mass of M_*_=(8+/-1)x10^10^ M_{sun}_, although there are systematic uncertainties of up to 5x for individual sources. Assuming that the star formation activity in SMGs has a timescale of ~100 Myr, we show that their descendants at z~0 would have a space density and M_H_ distribution that are in good agreement with those of local ellipticals. In addition, the inferred mass-weighted ages of the local ellipticals broadly agree with the look-back times of the SMG events. Taken together, these results are consistent with a simple model that identifies SMGs as events that form most of the stars seen in the majority of luminous elliptical galaxies at the present day.
- ID:
- ivo://CDS.VizieR/J/PASP/123/659
- Title:
- Analysis of flares of V1285 Aql
- Short Name:
- J/PASP/123/659
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Statistically analysing Johnson UBVR observations of V1285 Aql during the three observing seasons, both activity level and behaviour of the star are discussed in respect to obtained results. We also discuss the variation out-of-flare due to rotational modulation.
- ID:
- ivo://CDS.VizieR/J/ApJS/212/18
- Title:
- An atlas of UV-to-MIR galaxy SEDs
- Short Name:
- J/ApJS/212/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an atlas of 129 spectral energy distributions for nearby galaxies, with wavelength coverage spanning from the ultraviolet to the mid-infrared. Our atlas spans a broad range of galaxy types, including ellipticals, spirals, merging galaxies, blue compact dwarfs, and luminous infrared galaxies. We have combined ground-based optical drift-scan spectrophotometry with infrared spectroscopy from Spitzer and Akari with gaps in spectral coverage being filled using Multi-wavelength Analysis of Galaxy Physical Properties spectral energy distribution models. The spectroscopy and models were normalized, constrained, and verified with matched-aperture photometry measured from Swift, Galaxy Evolution Explorer, Sloan Digital Sky Survey, Two Micron All Sky Survey, Spitzer, and Wide-field Infrared Space Explorer images. The availability of 26 photometric bands allowed us to identify and mitigate systematic errors present in the data. Comparison of our spectral energy distributions with other template libraries and the observed colors of galaxies indicates that we have smaller systematic errors than existing atlases, while spanning a broader range of galaxy types. Relative to the prior literature, our atlas will provide improved K-corrections, photometric redshifts, and star-formation rate calibrations.
- ID:
- ivo://CDS.VizieR/J/AJ/154/269
- Title:
- A new photo-z method for quasars in Stripe 82
- Short Name:
- J/AJ/154/269
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new algorithm to estimate quasar photometric redshifts (photo-zs), by considering the asymmetries in the relative flux distributions of quasars. The relative flux models are built with multivariate Skew-t distributions in the multidimensional space of relative fluxes as a function of redshift and magnitude. For 151392 quasars in the SDSS, we achieve a photo-z accuracy, defined as the fraction of quasars with the difference between the photo-z z_p_ and the spectroscopic redshift z_s_, |{Delta}_z_|=|z_s_-z_p_|/(1+z_s_) within 0.1, of 74%. Combining the WISE W1 and W2 infrared data with the SDSS data, the photo-z accuracy is enhanced to 87%. Using the Pan-STARRS1 or DECaLS photometry with WISE W1 and W2 data, the photo-z accuracies are 79% and 72%, respectively. The prior probabilities as a function of magnitude for quasars, stars, and galaxies are calculated, respectively, based on (1) the quasar luminosity function, (2) the Milky Way synthetic simulation with the Besancon model, and (3) the Bayesian Galaxy Photometric Redshift estimation. The relative fluxes of stars are obtained with the Padova isochrones, and the relative fluxes of galaxies are modeled through galaxy templates. We test our classification method to select quasars using the DECaLS g, r, z, and WISE W1 and W2 photometry. The quasar selection completeness is higher than 70% for a wide redshift range 0.5<z<4.5, and a wide magnitude range 18<r<21.5 mag. Our photo-z regression and classification method has the potential to extend to future surveys. The photo-z code will be publicly available.
- ID:
- ivo://CDS.VizieR/J/ApJ/725/200
- Title:
- An updated catalog of M31 globular-like clusters
- Short Name:
- J/ApJ/725/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an updated UBVRI photometric catalog containing 970 objects in the field of M31, selected from the Revised Bologna Catalog (RBC v.4.0), including 965, 967, 965, 953, and 827 sources in the individual UBVRI bands, respectively, of which 205, 123, 14, 126, and 109 objects do not have previously published photometry. Photometry is performed using archival images from the Local Group Galaxies Survey, which covers 2.2deg^2^ along the major axis of M31. Detailed comparisons show that our photometry is fully consistent with previous measurements in all filters. We focus on 445 confirmed "globular-like" clusters and candidates, comprising typical globular and young massive clusters. The ages and masses of these objects are derived by comparing their observed spectral-energy distributions with simple stellar population synthesis. Approximately half of the clusters are younger than 2Gyr, suggesting that there has been significant recent active star formation in M31, which is consistent with previous results.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/577
- Title:
- AO 0235+164 BVRI photometry
- Short Name:
- J/A+AS/129/577
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the optical and radio monitoring of the BL Lac object AO 0235+164 during a faint state. In both optical and radio bands the source has been observed at the faintest ever recorded levels, reaching V=19.80 and F_22GHz_=0.34Jy. In the optical bands we still see variability with amplitudes up to 1.5 magnitudes on timescales from days to weeks. The radio variability is less dramatic, but in general follows the optical behaviour. A correlation between general trends in the optical and radio behaviour of AO 0235+164 may be recognized in the data from the present monitoring as well as in the historical light curves, suggesting a `base' mechanism responsible for the emission at both frequencies. A good candidate is a synchrotron process in the relativistic jet. Optical flares with no corresponding radio counterparts have been observed too. These events may be interpreted in terms of microlensing by a foreground galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/806/248
- Title:
- AO imaging of KOIs with gas giant planets
- Short Name:
- J/ApJ/806/248
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As hundreds of gas giant planets have been discovered, we study how these planets form and evolve in different stellar environments, specifically in multiple stellar systems. In such systems, stellar companions may have a profound influence on gas giant planet formation and evolution via several dynamical effects such as truncation and perturbation. We select 84 Kepler Objects of Interest (KOIs) with gas giant planet candidates. We obtain high-angular resolution images using telescopes with adaptive optics (AO) systems. Together with the AO data, we use archival radial velocity data and dynamical analysis to constrain the presence of stellar companions. We detect 59 stellar companions around 40 KOIs for which we develop methods of testing their physical association. These methods are based on color information and galactic stellar population statistics. We find evidence of suppressive planet formation within 20 AU by comparing stellar multiplicity. The stellar multiplicity rate (MR) for planet host stars is 0_-0_^+5^% within 20 AU. In comparison, the stellar MR is 18%+/-2% for the control sample, i.e., field stars in the solar neighborhood. The stellar MR for planet host stars is 34%+/-8% for separations between 20 and 200 AU, which is higher than the control sample at 12%+/-2%. Beyond 200 AU, stellar MRs are comparable between planet host stars and the control sample. We discuss the implications of the results on gas giant planet formation and evolution.
- ID:
- ivo://CDS.VizieR/J/ApJ/672/40
- Title:
- AO 0235+164 outburst in 2006 December
- Short Name:
- J/ApJ/672/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of polarimetric (R-band) and multicolor photometric (BVRIJHK) observations of the blazar AO 0235+16 during an outburst in 2006 December. The data reveal a short timescale of variability (several hours), which increases from optical to near-IR wavelengths; even shorter variations are detected in polarization. The flux density correlates with the degree of polarization, and at the maximum degree of polarization the electric vector tends to align with the parsec-scale jet direction. We find that a variable component with a steady power-law spectral energy distribution and very high optical polarization (30%-50%) is responsible for the variability. We interpret these properties of the blazar within a model of a transverse shock propagating down the jet. In this case a small change in the viewing angle of the jet, by ~<1{deg}, and a decrease in the shocked plasma compression by a factor of ~1.5 are sufficient to account for the variability.
- ID:
- ivo://CDS.VizieR/J/AJ/148/81
- Title:
- APASS BVgri photometry of RAVE stars. I. Data
- Short Name:
- J/AJ/148/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide AAVSO Photometric All-Sky Survey (APASS) photometry in the Landolt BV and Sloan g'r'i' bands for all 425743 stars included in the fourth RAVE Data Release. The internal accuracy of the APASS photometry of RAVE stars, expressed as the error of the mean of data obtained and separately calibrated over a median of four distinct observing epochs and distributed between 2009 and 2013, is 0.013, 0.012, 0.012, 0.014, and 0.021mag for the B, V, g', r', and i' bands, respectively. The equally high external accuracy of APASS photometry has been verified on secondary Landolt and Sloan photometric standard stars not involved in the APASS calibration process and on a large body of literature data on field and cluster stars, confirming the absence of offsets and trends. Compared with the Carlsberg Meridian Catalog (CMC-15), APASS astrometry of RAVE stars is accurate to a median value of 0.098arcsec. Brightness distribution functions for the RAVE stars have been derived in all bands. APASS photometry of RAVE stars, augmented by 2MASS JHK infrared data, has been {chi}^2^ fitted to a densely populated synthetic photometric library designed to widely explore temperature, surface gravity, metallicity, and reddening. Resulting T_eff_ and E_B-V_, computed over a range of options, are provided and discussed, and will be kept updated in response to future APASS and RAVE data releases. In the process, we find that the reddening caused by a homogeneous slab of dust, extending for 140pc on either side of the Galactic plane and responsible for E_B-V_^poles^=0.036+/-0.002 at the Galactic poles, is a suitable approximation of the actual reddening encountered at Galactic latitudes|b|>=25{deg}.
- ID:
- ivo://CDS.VizieR/J/ApJS/236/27
- Title:
- APOGEE-2 survey of Orion Complex (OSFC). I.
- Short Name:
- J/ApJS/236/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Orion Star-forming Complex (OSFC) is a central target for the APOGEE-2 Young Cluster Survey. Existing membership catalogs span limited portions of the OSFC, reflecting the difficulty of selecting targets homogeneously across this extended, highly structured region. We have used data from wide-field photometric surveys to produce a less biased parent sample of young stellar objects (YSOs) with infrared (IR) excesses indicative of warm circumstellar material or photometric variability at optical wavelengths across the full 420deg^2^ extent of the OSFC. When restricted to YSO candidates with H<12.4, to ensure S/N~100 for a six-visit source, this uniformly selected sample includes 1307 IR excess sources selected using criteria vetted by Koenig & Leisawitz (2014ApJ...791..131K) and 990 optical variables identified in the Pan-STARRS1 3{pi} survey: 319 sources exhibit both optical variability and evidence of circumstellar disks through IR excess. Objects from this uniformly selected sample received the highest priority for targeting, but required fewer than half of the fibers on each APOGEE-2 plate. We filled the remaining fibers with previously confirmed and new color-magnitude selected candidate OSFC members. Radial velocity measurements from APOGEE-1 and new APOGEE-2 observations taken in the survey's first year indicate that ~90% of the uniformly selected targets have radial velocities consistent with Orion membership. The APOGEE-2 Orion survey will include >1100 bona fide YSOs whose uniform selection function will provide a robust sample for comparative analyses of the stellar populations and properties across all sub-regions of Orion.
- ID:
- ivo://CDS.VizieR/J/AJ/128/463
- Title:
- A preliminary 20pc census from the NLTT catalogue
- Short Name:
- J/AJ/128/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuing our census of late-type dwarfs in the solar neighborhood, we present BVRI photometry and optical spectroscopy of 800 mid-type M dwarfs drawn from the NLTT proper-motion catalog. The targets are taken both from our own cross-referencing of the NLTT Catalogue and the 2MASS Second Incremental Data Release, and from the revised NLTT compiled recently by Salim & Gould (Cat. <J/ApJ/582/1011>). All are identified as nearby-star candidates based on their location in the (m_r_, m_r_-K_s_) diagram. Three hundred stars discussed here have previous astrometric, photometric, or spectroscopic observations. We present new BVRI photometry for 101 stars, together with low-resolution spectroscopy of a further 400 dwarfs.
- ID:
- ivo://CDS.VizieR/J/AJ/132/2556
- Title:
- ARAUCARIA project: Cepheids in NGC 55
- Short Name:
- J/AJ/132/2556
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have detected, for the first time, Cepheid variables in the Sculptor Group SB(s)m galaxy NGC 55. From wide-field images obtained in the optical V and I bands during 77 nights in 2002-2003, we have found 143 Cepheids with periods ranging from 5.6 to 175.9 days; 133 of these objects have periods longer than 10 days, making NGC 55 to date the galaxy with the largest known number of long-period Cepheids in the Sculptor Group.
- ID:
- ivo://CDS.VizieR/J/AJ/128/2815
- Title:
- ARAUCARIA project: NGC 6822 Cepheid variables
- Short Name:
- J/AJ/128/2815
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained mosaic images of NGC 6822 in the V and I bands on 77 nights. From these data, we have conducted an extensive search for Cepheid variables over the entire field of the galaxy, and we have found 116 such variables with periods ranging from 1.7 to 124 days. We used the long-period (>5.6 days) Cepheids to establish the period-luminosity (PL) relations in V, I, and in the reddening-independent Wesenheit index, which are all very tightly defined.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1167
- Title:
- ARAUCARIA project : NGC 300 Cepheid Variables. II
- Short Name:
- J/AJ/128/1167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VI data, derive improved periods and mean magnitudes for the variables, and construct period-luminosity relations in the V, I, and the reddening-independent V-I Wesenheit bands using 58 Cepheid variables with periods between 11 and 90 days.
- ID:
- ivo://CDS.VizieR/J/AJ/138/478
- Title:
- AR Boo differential BVR photometry
- Short Name:
- J/AJ/138/478
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD photometric observations of the eclipsing system AR Boo were obtained from 2006 February to 2008 April. The star's photometric properties are derived from detailed studies of the period variability and of all available light curves.
- ID:
- ivo://CDS.VizieR/J/AJ/161/203
- Title:
- A sample of 7146 M or K-dwarfs from KIC and Gaia
- Short Name:
- J/AJ/161/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The planet-metallicity correlation serves as a potential link between exoplanet systems as we observe them today and the effects of bulk composition on the planet formation process. Many observers have noted a tendency for Jovian planets to form around stars with higher metallicities; however, there is no consensus on a trend for smaller planets. Here, we investigate the planet-metallicity correlation for rocky planets in single and multi-planet systems around Kepler M-dwarf and late-K-dwarf stars. Due to molecular blanketing and the dim nature of these low-mass stars, it is difficult to make direct elemental abundance measurements via spectroscopy. We instead use a combination of accurate and uniformly measured parallaxes and photometry to obtain relative metallicities and validate this method with a subsample of spectroscopically determined metallicities. We use the Kolmogorov-Smirnov (K-S) test, Mann-Whitney U-test, and Anderson-Darling (AD) test to compare the compact multiple planetary systems with single-transiting planet systems and systems with no detected transiting planets. We find that the compact multiple planetary systems are derived from a statistically more metal-poor population, with a p-value of 0.015 in the K-S test, a p-value of 0.005 in the Mann-Whitney U-test, and a value of 2.574 in the AD test statistic, which exceeds the derived threshold for significance by a factor of 25. We conclude that metallicity plays a significant role in determining the architecture of rocky planet systems. Compact multiples either form more readily, or are more likely to survive on gigayear timescales, around metal-poor stars.
- ID:
- ivo://CDS.VizieR/II/366
- Title:
- ASAS-SN catalog of variable stars
- Short Name:
- II/366
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The All-Sky Automated Survey for Supernovae (ASAS-SN) is the first optical survey to routinely monitor the whole sky with a cadence of ~2-3d down to V<~17mag. ASAS-SN has monitored the whole sky since 2014, collecting ~100-500 epochs of observations per field. The V-band light curves for candidate variables identified during the search for supernovae are classified using a random forest classifier and visually verified. In Paper I (Jayasinghe+ 2018MNRAS.477.3145J), we present a catalogue of 66179 bright, new variable stars discovered during our search for supernovae, including 27479 periodic variables and 38700 irregular variables. In paper II (Jayasinghe+ 2019MNRAS.486.1907J), We extracted the ASAS-SN light curves of ~412000 variable stars previously discovered by other surveys and in the VSX catalogue. In paper III (Jayasinghe+ 2019MNRAS.485..961J), we extracted the ASAS-SN light curves of ~1.3 million sources within 18deg of the Southern Ecliptic Pole. These sources are within the southern TESS CVZ and will have well-sampled TESS light curves.
- ID:
- ivo://CDS.VizieR/J/MNRAS/463/3813
- Title:
- ASASSN-15oi UBVI M2W1W2 light curves
- Short Name:
- J/MNRAS/463/3813
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ground-based and Swift photometric and spectroscopic observations of the tidal disruption event (TDE) ASASSN-15oi, discovered at the centre of 2MASX J20390918-3045201 (d~=216Mpc) by the All-Sky Automated Survey for SuperNovae. The source peaked at a bolometric luminosity of L~=1.3x10^44^erg/s and radiated a total energy of E~=6.6x10^50^ erg over the first ~3.5 months of observations. The early optical/UV emission of the source can be fit by a blackbody with temperature increasing from T~=2x10^4^K to T~=4x10^4^K while the luminosity declines from L~=1.3x10^44^erg/s to L~=2.3x10^43^erg/s, requiring the photosphere to be shrinking rapidly. The optical/UV luminosity decline during this period is most consistent with an exponential decline, L{prop.to}e^-(t-t_0)/tau_^, with {tau}~=46.5d for t_0_~=57241.6 (MJD), while a power-law decline of L{prop.to}(t-t_0_)^-{alpha}^ with t_0_~=57212.3 and {alpha}=1.62 provides a moderately worse fit. ASASSN-15oi also exhibits roughly constant soft X-ray emission that is significantly weaker than the optical/UV emission. Spectra of the source show broad helium emission lines and strong blue continuum emission in early epochs, although these features fade rapidly and are not present ~3 months after discovery. The early spectroscopic features and colour evolution of ASASSN-15oi are consistent with a TDE, but the rapid spectral evolution is unique among optically selected TDEs.
- ID:
- ivo://CDS.VizieR/J/AcA/59/33
- Title:
- ASAS. Variable stars catalog in Kepler field.
- Short Name:
- J/AcA/59/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog is a result of the analysis of VI photometry obtained during the first 17-month observations in the ASAS3-North station. The variable stars we present are divided into eleven groups according to the presented variability; the groups are briefly discussed. The catalog is intended to be a source of information for target selection process and follow-up programs.
- ID:
- ivo://CDS.VizieR/J/other/NewA/51.1
- Title:
- AS CrB BVRI light curves
- Short Name:
- J/other/NewA/51.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first high-precision BVRI light curves of the eclipsing binary AS CrB were presented and were analyzed by the 2015 version of the W-D code. It is found that AS CrB is an extreme mass-ratio, deep contact binary with a fill-out factor of f=59.6+/-2.5% and a mass ratio of q=0.172+/-0.008q=0.172+/-0.008. Based on the photometric solution and the Dartmouth isochrones model, the masses, radii, and luminosities of the components are estimated as follows: M_1_=1.25+/-0.15M_{sun}_, M_1_=1.25+/-0.15M_{sun}_, M_2_=0.21+/-0.06M_{sun}_, M_2_=0.21+/-0.06M_{sun}_, R_1_=1.40+/-0.07R_{sun}_, R_1_=1.40+/-0.07R_{sun}_, R_2_=0.67+/-0.04R_{sun}_, R_2_=0.67+/-0.04R_{sun}_, L_1_=3.2+/-0.2L_{sun}_, L_1_=3.2+/-0.2L_{sun}_, and L_2_=0.72+/-0.04L_{sun}_, L_2_=0.72+/-0.04L_{sun}_, with an estimated distance 459+/-42pc. These uncertainties mainly come from the errors of the color used to estimate the temperature of the primary star. By investigating all of the available times of light minima, it is found that the Observed-Calculated [(O-C)(O-C)] curve shows a long-term period increase, with a rate of dP/dt=+(3.46+/-0.01)x10^-7^dP/dt=+(3.46+/-0.01)x10^-7^day/year. As an extreme mass-ratio contact binary, AS CrB may merge into a single star, such as an FK Com-type star or a blue straggler, because of the orbital instability.
- ID:
- ivo://CDS.VizieR/J/A+AS/130/65
- Title:
- A standard stellar library. II.
- Short Name:
- J/A+AS/130/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A standard library of theoretical stellar spectra intended for multiple synthetic photometry applications including spectral evolutionary synthesis is presented. The grid includes M dwarf model spectra, hence complementing the first library version established in Paper I (Lejeune et al., 1997, Cat. <J/A+AS/125/229>). It covers the following wide ranges of fundamental parameters: Teff: 50,000 to 2000K, logg: 5.5 to -1.02, and [Fe/H]: +1.0 to -5.0. A correction procedure is also applied to the theoretical spectra in order to provide color-calibrated flux distributions over a large domain of effective temperatures. Empirical Teff-color calibrations are constructed between 11500K and 2000K, and semi-empirical calibrations for non-solar abundances ([Fe/H]=-3.5 to +1.0) are established. Model colors and bolometric corrections for both the original and the corrected spectra, synthesized in the UBV(RI)c(JHKLL'M) system, are given for the full range of stellar parameters. Synthetic colors: ---------------- Synthetic UBV(RI)c(JHKLM) colors have been computed from both the original and the corrected model flux distributions presented in Paper I (1997A&AS..125..229L; see catalog <J/A+AS/125/229>), as the files lcb98ori.dat and lcb98cor.dat respectively; the results are also presented in individual files lcb98xxx.ori and lcb98xxx.cor, where xxx designates the metallicity (ex: 'm15' --> [Fe/H]=-1.5). For each file, we give synthetic colors computed from energy-weighted and photon-weighted stellar fluxes. Semi-empirical calibrations: --------------------------- Empirical ([Fe/H]=0.0) and semi-empirical (-3.5<=[Fe/H]<=+1.0) Teff-colors (UBVRIJHKLM) calibrations are given in Tables 1 to 10.
- ID:
- ivo://CDS.VizieR/J/PASP/116/1012
- Title:
- A star catalog for the open cluster NGC 188
- Short Name:
- J/PASP/116/1012
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new BVRI broadband photometry for the old open cluster NGC 188, based on an analysis of 299 CCD images either obtained by us, donated by colleagues, or retrieved from public archives.
- ID:
- ivo://CDS.VizieR/J/ApJS/226/21
- Title:
- ASTEP catalog of EB* and variable stars
- Short Name:
- J/ApJS/226/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the large photometric database of the ASTEP program, whose primary goal was to detect exoplanets in the southern hemisphere from Antarctica, to search for eclipsing binaries (EcBs) and variable stars. 673 EcBs and 1166 variable stars were detected, including 31 previously known stars. The resulting online catalogs give the identification, the classification, the period, and the depth or semi-amplitude of each star. Data and light curves for each object are available at http://astep-vo.oca.eu/.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A80
- Title:
- Asteroides phase curves using SLOAN MOC
- Short Name:
- J/A+A/657/A80
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Large photometric surveys are producing, and will continue doing it, massive amounts of data on small bodies. Usually,these data will be sparsely obtained at arbitrary (and unknown) rotational phases. Therefore, new methods to process such data need to be developed to make the most of those large catalogs. We aim to produce a method to create phase curves of small bodies considering the uncertainties introduced not only by the nominal errors in the magnitudes, but also the effect introduced by rotational variations.We use as a benchmark the data from the SLOAN Moving Objects Catalog with the objective to construct phase curves of all small bodies in there, in the u, g, r, i, and z, filters. We will obtain from the phase curves the absolute magnitudes and set up with them the absolute colors, which are the colors of the asteroids not affected by changes in phase angle. We select objects with >3 observations taken in, at least, one filter and spanned over a minimum of 5 degrees in phase angle. We developed a method that combines Monte Carlo simulations and Bayesian inference to estimate the absolute magnitudes using the HG12 photometric system. We obtained almost 15000 phase curves, about 12000 including all five filters. The absolute magnitudes and absolute colors are compatible with previously published data, supporting our method.Conclusions. The method we developed is fully automatic and well suited to be run on large amounts of data. Moreover, it includes the nominal uncertainties in the magnitudes and the whole distribution of possible rotational states of the objects producing, possibly,less precise values, i.e., larger uncertainties, but more accurate, i.e., closer to the real value. To the best of our knowledge, this work is the first to include the effect of rotational variations in such a way.
- ID:
- ivo://CDS.VizieR/J/AJ/155/252
- Title:
- Astrometry & photometry of dwarf carbon stars
- Short Name:
- J/AJ/155/252
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Parallaxes are presented for a sample of 20 nearby dwarf carbon stars. The inferred luminosities cover almost two orders of magnitude. Their absolute magnitudes and tangential velocities confirm prior expectations that some originate in the Galactic disk, although more than half of this sample are halo stars. Three stars are found to be astrometric binaries, and orbital elements are determined; their semimajor axes are 1-3 au, consistent with the size of an AGB mass-transfer donor star.
- ID:
- ivo://CDS.VizieR/J/PAZh/25/115
- Title:
- A study of the open cluster NGC 6811
- Short Name:
- J/PAZh/25/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 191 individual measurements of radial velocities made with CORAVEL-type spectrometer are presented for 60 stars in the large region of NGC 6811 open cluster. Photoelectric UBVR magnitudes are given for 117 stars - members of the cluster by proper motions. Spectral classification of these stars is taken from Straizys and Kazlauskas (1993BaltA...2....1S).
- ID:
- ivo://CDS.VizieR/J/A+A/653/A134
- Title:
- AT 2018bwo light curves
- Short Name:
- J/A+A/653/A134
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Luminous red novae (LRNe) are astrophysical transients associated with the partial ejection of a binary system's common envelope (CE) shortly before its merger. Here we present the results of our photometric and spectroscopic follow-up campaign of AT 2018bwo (DLT 18x), a LRN discovered in NGC 45, and investigate its progenitor system using binary stellar-evolution models. The transient reached a peak magnitude of M_r_=-10.97+/-0.11 and maintained this brightness during its optical plateau of t_p_=41+/-5d ays. During this phase, it showed a rather stable photospheric temperature of ~3300K and a luminosity of ~10^40^erg/s. Although the luminosity and duration of AT 2018bwo is comparable to the LRNe V838 Mon and M31-2015LRN, its photosphere at early times appears larger and cooler, likely due to an extended mass-loss episode before the merger. Toward the end of the plateau, optical spectra showed a reddened continuum with strong molecular absorption bands. The IR spectrum at +103 days after discovery was comparable to that of an M8.5 II type star, analogous to an extended AGB star. The reprocessed emission by the cooling dust was also detected in the mid-infrared bands ~1.5 years after the outburst. Archival Spitzer and Hubble Space Telescope data taken 10-14yrs before the transient event suggest a progenitor star with T_prog_~6500K, R_prog_~100R_{sun}_, and L_prog_=2x10^4^L_{sun}_, and an upper limit for optically thin warm (1000K) dust mass of M_d_<10^-6^M_{sun}_. Using stellar binary-evolution models, we determined the properties of binary systems consistent with the progenitor parameter space. For AT 2018bwo, we infer a primary mass of 12-16M_{sun}_, which is 9-45% larger than the ~11M_{sun}_ obtained using single-star evolution models. The system, consistent with a yellow-supergiant primary, was likely in a stable mass-transfer regime with -2.4 <= log (M_dot/Msun /yr) <= -1.2 a decade before the main instability occurred. During the dynamical merger, the system would have ejected 0.15-0.5M_{sun}_ with a velocity of ~500km/s.
- ID:
- ivo://CDS.VizieR/J/A+A/647/A93
- Title:
- AT 2020hat and AT 2020kog light curves
- Short Name:
- J/A+A/647/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of our monitoring campaigns of the luminous red novae (LRNe) AT 2020hat in NGC 5068 and AT 2020kog in NGC 6106. The two objects were imaged (and detected) before their discovery by routine survey operations. They show a general trend of slow luminosity rise lasting at least a few months. The subsequent major LRN outbursts were extensively followed in photometry and spectroscopy. The light curves present an initial short-duration peak, followed by a redder plateau phase. AT 2020kog is a moderately luminous event peaking at ~7x10^40^erg/s, while AT 2020hat is almost one order of magnitude fainter than AT 2020kog, although it is still more luminous than V838 Mon. In analogy with other LRNe, the spectra of AT 2020kog change significantly with time. They resemble those of type IIn supernovae at early phases, then they become similar to those of K-type stars during the plateau, and to M-type stars at very late phases. In contrast, AT 2020hat already shows a redder continuum at early epochs, and its spectrum shows the late appearance of molecular bands. A moderate-resolution spectrum of AT 2020hat taken at +37d after maximum shows a forest of narrow P Cygni lines of metals with velocities of 180 km/s, along with an Halpha emission with a full-width at half-maximum velocity of 250km/s. For AT 2020hat, a robust constraint on its quiescent progenitor is provided by archival images of the Hubble Space Telescope. The progenitor is clearly detected as a mid-K type star, with an absolute magnitude of M_F606W=-3.33+/-0.09mag and a colour of F606W-F814W=1.14+/-0.05mag, which are inconsistent with the expectations from a massive star that could later produce a core-collapse supernova. Although quite peculiar, the two objects nicely match the progenitor versus light curve absolute magnitude correlations discussed in the literature.
- ID:
- ivo://CDS.VizieR/J/A+A/632/L6
- Title:
- AT 2018hso light curves and spectra
- Short Name:
- J/A+A/632/L6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The absolute magnitudes of luminous red novae (LRNe) are intermediate between those of novae and supernovae (SNe), and show a relatively homogeneous spectro-photometric evolution. Although they were thought to derive from core instabilities in single stars, there is growing support for the idea that they are triggered by binary interaction that possibly ends with the merging of the two stars. AT 2018hso is a new transient showing transitional properties between those of LRNe and the class of intermediate-luminosity red transients (ILRTs) similar to SN 2008S. Through the detailed analysis of the observed parameters, our study support that it actually belongs to the LRN class and was likely produced by the coalescence of two massive stars. We obtained ten months of optical and near-infrared photometric monitoring, and 11 epochs of low-resolution optical spectroscopy of AT 2018hso. We compared its observed properties with those of other ILRTs and LRNe. We also inspected the archival Hubble Space Telescope (HST) images obtained about 15 years ago to constrain the progenitor properties. The light curves of AT 2018hso show a first sharp peak (reddening-corrected M_r_=13.93mag), followed by a broader and shallower second peak that resembles a plateau in the optical bands. The spectra dramatically change with time. Early-time spectra show prominent Balmer emission lines and a weak [CaII] doublet, which is usually observed in ILRTs. However, the strong decrease in the continuum temperature, the appearance of narrow metal absorption lines, the great change in the H{alpha} strength and profile, and the emergence of molecular bands support an LRN classification. The possible detection of a M_I_~8mag source at the position of AT 2018hso in HST archive images is consistent with expectations for a pre-merger massive binary, similar to the precursor of the 2015 LRN in M101. We provide reasonable arguments to support an LRN classification for AT 2018hso. This study reveals growing heterogeneity in the observables of LRNe than has been thought previously, which is a challenge for distinguishing between LRNe and ILRTs. This suggests that the entire evolution of gap transients needs to be monitored to avoid misclassifications.
- ID:
- ivo://CDS.VizieR/J/AJ/153/107
- Title:
- Australian Dark Energy Survey (OzDES) quasar catalog
- Short Name:
- J/AJ/153/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of quasar selection using the supernova fields of the Dark Energy Survey (DES). We used a quasar catalog from an overlapping portion of the SDSS Stripe 82 region to quantify the completeness and efficiency of selection methods involving color, probabilistic modeling, variability, and combinations of color/probabilistic modeling with variability. In all cases, we considered only objects that appear as point sources in the DES images. We examine color selection methods based on the Wide-field Infrared Survey Explorer (WISE) (Wright et al. 2010AJ....140.1868W) mid-IR W1-W2 color, a mixture of WISE and DES colors (g-i and i-W1), and a mixture of Vista Hemisphere Survey (McMahon et al. 2013Msngr.154...35M) and DES colors (g-i and i-K). For probabilistic quasar selection, we used XDQSO, an algorithm that employs an empirical multi-wavelength flux model of quasars to assign quasar probabilities. Our variability selection uses the multi-band {chi}^2^-probability that sources are constant in the DES Year 1 griz-band light curves. The completeness and efficiency are calculated relative to an underlying sample of point sources that are detected in the required selection bands and pass our data quality and photometric error cuts. We conduct our analyses at two magnitude limits, i<19.8 mag and i<22 mag. For the subset of sources with W1 and W2 detections, the W1-W2 color or XDQSOz method combined with variability gives the highest completenesses of >85% for both i-band magnitude limits and efficiencies of >80% to the bright limit and >60% to the faint limit; however, the giW1 and giW1+variability methods give the highest quasar surface densities. The XDQSOz method and combinations of W1W2/giW1/XDQSOz with variability are among the better selection methods when both high completeness and high efficiency are desired. We also present the OzDES Quasar Catalog of 1263 spectroscopically confirmed quasars from three years of OzDES observation in the 30 deg^2^ of the DES supernova fields. The catalog includes quasars with redshifts up to z~4 and brighter than i=22 mag, although the catalog is not complete up to this magnitude limit.
- ID:
- ivo://CDS.VizieR/J/A+A/536/A27
- Title:
- AX Per UBVRI photometry
- Short Name:
- J/A+A/536/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- AX Per is an eclipsing symbiotic binary. During active phases, deep narrow minima are observed in its light curve, and the ionization structure in the binary changes significantly. From ~2007.5, AX Per entered a new active phase. We aim to derive the ionization structure in the binary and its changes during the recent active phase. We used optical high- and low-resolution spectroscopy and UBVRcIc photometry. We modeled the SED in the optical and broad wings of the H alpha line profile during the 2007-10 higher level of the AX Per activity. After 10 orbital cycles (~18.6 years), we again measured the eclipse of the hot component by its giant companion in the light curve. We derived a radius of 27+/-2R_{sun}_ for the eclipsed object and 115+/-2R_{sun}_ for the eclipsing cool giant. The new active phase was connected with a significant enhancement of the hot star wind. From quiescence to activity, the mass-loss rate increased from ~9E-8 to ~3E-6M_{sun}_/yr, respectively. The wind causes the emission of the He++ zone, located in the vicinity of the hot star, and also is the reason for the fraction of the [OIII] zone at farther distances. Simultaneously, we identified a variable optically thick warm (T_eff_~6000K) source that contributes markedly to the composite spectrum. The source was located at the hot star's equator and has the form of a flared disk, whose outer rim simulates the warm photosphere. The formation of the neutral disk-like zone around the accretor during the active phase was connected with its enhanced wind. It is probable that this connection represents a common origin of the warm pseudophotospheres that are indicated during the active phases of symbiotic stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/1241
- Title:
- Be 81, NGC 1917 and NGC 2141 BVI photometry
- Short Name:
- J/MNRAS/437/1241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we analyse the evolutionary status of three open clusters: NGC 1817, NGC 2141 and Berkeley 81. They are all of intermediate age, two are located in the Galactic anticentre direction while the third one is located in the Galactic Centre direction. All of them were observed with Large Binocular Camera at Large Binocular Telescope using the Bessel B, V and I filters. The cluster parameters have been obtained using the synthetic colour-magnitude diagram (CMD) method, i.e. the direct comparison of the observational CMDs with a library of synthetic CMDs generated with different evolutionary sets (Padova, FRANEC and FST). This analysis shows that NGC 1817 has subsolar metallicity, age between 0.8 and 1.2Gyr, reddening E(B-V) in the range 0.21 and 0.34 and distance modulus (m-M)_0_ of about 10.9; NGC 2141 is older, with age in the range 1.25 and 1.9Gyr, E(B-V) between 0.36 and 0.45, (m-M)_0_ between 11.95 and 12.21 and subsolar metallicity; Berkeley 81 has metallicity about solar, with age between 0.75 and 1.0Gyr, has reddening E(B-V)~0.90 and distance modulus (m-M)_0~12.4. Exploiting the large field of view of the instrument we derive the structure parameters for NGC 2141 and Berkeley 81 by fitting a King profile to the estimated density profile. Combining this information with the synthetic CMD technique we estimate a lower limit for the cluster total mass for these two systems.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/429
- Title:
- Berkeley 94 and Berkeley 96 UBVRcIcJHKs
- Short Name:
- J/MNRAS/435/429
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed multiband UBVRcIcJHKs photometry of two young clusters located at large Galactocentric distances in the direction of the Perseus spiral arm. The obtained distances and colour excesses amount to 3.9+/-0.11kpc, E(B-V)=0.62+/-0.05 for Berkeley 94, and 4.3+/-0.15kpc, E(B-V)=0.58+/-0.06 for Berkeley 96. The respective ages, as measured from the comparison of the upper colour-magnitude diagrams to model isochrones, amount to log10Age(yr)=7.5+/-0.07 and 7.0+/-0.07, respectively. A sequence of optical pre-main-sequence (PMS) members is proposed in both clusters. In addition, samples of objects showing (H-Ks) excess are found. Part of these are suggested to be PMS cluster members of lower mass than the optical candidates. The spatial distribution of these sources, the comparison to Galactic models and to the expected number of contaminating distant red galaxies, and the spectral energy distribution in particular cases support this suggestion. The spatial distributions shown by members in different mass ranges can be interpreted in terms of the results from numerical simulations. According to these, different initial conditions and evolutionary dynamical paths are suggested for the clusters. Berkeley 94 would have formed under supervirial conditions, and followed the so-called warm collapse model in its evolution, whereas Berkeley 96 would have formed with a subvirial structure, and would have evolved following a cold collapse path. Both processes would be able to reproduce the suggested degree of mass segregation and their spatial distribution by mass range. Finally, the mass distributions of the clusters, from the most massive stars down to PMS stars around 1.3M_{sun}_, are calculated. An acceptable general agreement with the Salpeter initial mass function slope is found.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/111
- Title:
- Berkeley 64 and 69 stars UBVRI photometry
- Short Name:
- J/A+AS/122/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVRI CCD photometry for previously unstudied open clusters (Be 64 and Be 69). Photometry has also been carried out for nearby fields to correct f or the effects of field stars contamination. From the colour-colour diagram the reddening for Be 64 and Be 69 is estimated to be ~1.05mag and ~0.65mag respectively. In case of Be 69 the comparison of observational colour-magnitude diagram (CMD) with the standard isochrones of VandenBerg (19855ApJS...58..711V) indicates an apparent discrepancy between the shape of the turnoff and isochrones. The morphological features of the CMDs of Be 69 are better understood in terms of convective overshooting. The comparison of CMDs of both the clusters with the convective overshoot models (Bertelli et al. 1994A&AS..106..275B) produces a good fit for a metallicity Z=0.008 and age =0.8-1.0Gyr. An apparent distance modulus (m-M)=16.2 and 14.3 has been estimated for Be 64 and Be 69, respectively, which corresponds to a distance of 3880+/-480pc and 2860+/-310pc, respectively.
- ID:
- ivo://CDS.VizieR/J/MNRAS/299/834
- Title:
- Berkeley 21 BVI photometry
- Short Name:
- J/MNRAS/299/834
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD BVI photometry of the old open cluster Berkeley 21, one of the most distant clusters in the Galactic anticentre direction, and possibly the lowest metallicity object in the open clusters sample. Its position and metal abundance make it very important for the study of the Galactic disc. Using the synthetic colour-magnitude diagram method, we estimate values for the distance modulus (m-M)_0_=13.4-13.6, reddening E(B-V)=0.74-0.78 (with possible differential absorption), and age= 2.2-2.5Gyr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/368/471
- Title:
- Berkeley 32 BVI photometry and spectroscopy
- Short Name:
- J/MNRAS/368/471
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained medium- and low-resolution spectroscopy and BVI CCD imaging of Berkeley 32, an old open cluster which lies in the anticentre direction. From the radial velocities of 48 stars in the cluster direction, we found that 31 of them, in crucial evolutionary phases, are probable cluster members, with an average radial velocity of +106.7(sigma=8.5)km/s . From isochrone fitting to the colour-magnitude diagrams of Berkeley 32, we have obtained an age of 6.3Gyr, (m-M)0=12.48 and E(B-V)=0.10. The best fit is obtained with Z=0.008. A consistent distance, (m-M)_0_~=12.6+/-0.1, has been derived from the mean magnitude of red clump stars with confirmed membership; we may assume (m-M)_0_~=12.55+/-0.1. The colour-magnitude diagram of the nearby field observed to check for field stars contamination looks intriguingly similar to that of the Canis Major overdensity.
- ID:
- ivo://CDS.VizieR/J/MNRAS/465/784
- Title:
- Berkeley 90. III. Cluster parameters
- Short Name:
- J/MNRAS/465/784
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The open cluster Berkeley 90 is the home to one of the most massive binary systems in the Galaxy, LS III +46 11, formed by two identical, very massive stars (O3.5 If* + O3.5 If*), and a second early-O system (LS III +46 12 with an O4.5 IV((f)) component at least). Stars with spectral types earlier than O4 are very scarce in the Milky Way, with no more than 20 examples. The formation of such massive stars is still an open question today, and thus the study of the environments where the most massive stars are found can shed some light on this topic. To this aim, we determine the properties and characterize the population of Berkeley 90 using optical, near-infrared and WISE photometry and optical spectroscopy. This is the first determination of these parameters with accuracy. We find a distance of 3.5+/-0.5kpc and a maximum age of 3Ma. The cluster mass is around 1000M_{sun}_ (perhaps reaching 1500M_{sun}_ if the surrounding population is added), and we do not detect candidate runaway stars in the area. There is a second population of young stars to the Southeast of the cluster that may have formed at the same time or slightly later, with some evidence for low-activity ongoing star formation.
- ID:
- ivo://CDS.VizieR/J/other/NewA/56.28
- Title:
- Be stars in MC star clusters NIR properties
- Short Name:
- J/other/NewA/56.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Magellanic Clouds are the nearby galaxies which are ideal to study the properties of metal poor stellar population. In this study, we explore the near-IR properties of optically identified classical Be stars in 19 star clusters in the Magellanic Clouds. From an optically identified sample of 835 Be stars we obtained the J, H, K magnitudes of 389 stars from the IRSF MCPS catalog. Among these, 247 stars (36.4%) are found in 9 clusters in the Large Magellanic Cloud and 142 stars (55.5%) in 10 clusters in the Small Magellanic Cloud. After correcting for reddening, we studied their NIR properties in the (H-K)_0_ vs (J-H)_0_ diagram. We identified 14 stars with abnormally large near IR excesses, which were removed from the analysis, there by restricting our study to 355 classical Be stars. We propose an extended area in the near-IR (H-K)_0_ vs (J-H)_0_ diagram as the diagnostic location of Classical Be stars in the Magellanic Clouds. We identified 14 stars to have near-IR excess, higher than those seen in classical Be stars. From the analysis based on spectral energy distribution and luminosity estimate, we found that 8 candidate Be stars may be Herbig Ae/Be stars. We identified a new sample of 6 sgB[e] stars, which when added to the sparse existing sample of 15 sgB[e] stars in the Magellanic Clouds can provide insight to understand the evolutionary link between sgB[e] stars and Luminous Blue variables.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/60
- Title:
- Bgri light curves of PTF11kmb and PTF12bho
- Short Name:
- J/ApJ/836/60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Palomar Transient Factory discoveries and the photometric and spectroscopic observations of PTF11kmb and PTF12bho. We show that both transients have properties consistent with the class of calcium-rich gap transients, specifically lower peak luminosities and rapid evolution compared to ordinary supernovae, and a nebular spectrum dominated by [CaII] emission. A striking feature of both transients is their host environments: PTF12bho is an intracluster transient in the Coma Cluster, while PTF11kmb is located in a loose galaxy group, at a physical offset ~150kpc from the most likely host galaxy. Deep Subaru imaging of PTF12bho rules out an underlying host system to a limit of M_R_>-8.0mag, while Hubble Space Telescope imaging of PTF11kmb reveals a marginal counterpart that, if real, could be either a background galaxy or a globular cluster. We show that the offset distribution of Ca-rich gap transients is significantly more extreme than that seen for SNe Ia or even short-hard gamma-ray bursts (sGRBs). Thus, if the offsets are caused by a kick, they require higher kick velocities and/or longer merger times than sGRBs. We also show that almost all Ca-rich transients found to date are in group and cluster environments with elliptical host galaxies, indicating a very old progenitor population; the remote locations could partially be explained by these environments having the largest fraction of stars in the intragroup/intracluster light following galaxy-galaxy interactions.
- ID:
- ivo://CDS.VizieR/J/ApJ/684/1143
- Title:
- BHB candidates in the Milky Way
- Short Name:
- J/ApJ/684/1143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive new constraints on the mass of the Milky Way's dark matter halo, based on 2401 rigorously selected blue horizontal-branch halo stars from SDSS DR6. This sample enables construction of the full line-of-sight velocity distribution at different galactocentric radii. To interpret these distributions, we compare them to matched mock observations drawn from two different cosmological galaxy formation simulations designed to resemble the Milky Way. This procedure results in an estimate of the Milky Way's circular velocity curve to ~60kpc, which is found to be slightly falling from the adopted value of 220km/s at the Sun's location, and implies M(<60kpc)=(4.0+/-0.7)x10^11^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/2118
- Title:
- Binarity in planetary nebula central stars
- Short Name:
- J/MNRAS/428/2118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We still do not know what causes aspherical planetary nebula (PN) morphologies. A plausible hypothesis is that they are due to the presence of a close stellar or substellar companion. So far, only ~40 binary central stars of PN have been detected, almost all of them with such short periods that their binarity is revealed by photometric variability. Here we have endeavoured to discover binary central stars at any separation, thus determining the unbiased binary fraction of central stars of PN. This number, when compared to the binary fraction of the presumed parent population, can give a first handle on the origin of PN. By detecting the central stars in the I band we have searched for cool companions.
- ID:
- ivo://CDS.VizieR/J/ApJ/875/124
- Title:
- Binary red supergiants. II. B-type companions
- Short Name:
- J/ApJ/875/124
- Date:
- 20 Jan 2022 11:13:46
- Publisher:
- CDS
- Description:
- The percentage of massive main-sequence OB stars in binary systems is thought to be as high as 100%. However, very few Galactic binary red supergiants (RSGs) have been identified, despite the fact that these stars are the evolved descendants of OB stars. As shown in our recent paper, binary RSGs will likely have B-type companions, as dictated by stellar evolution considerations. Such a system will have a very unique photometric signature due to the shape of the spectral energy distribution. Using photometric cutoffs, it should therefore be possible to detect candidate RSG+B star binary systems. Here we present our spectroscopic follow-up observations of such candidates. Out of our initial list of 280 candidates in M31 and M33, we observed 149 and confirmed 63 as newly discovered RSG+B star binary systems. Additional spectra of four candidate systems in the Small Magellanic Cloud confirmed all of them as new RSG+B star binaries including the first known RSG+Be star system. By fitting BSTAR06 and MARCS model atmospheres to the newly obtained spectra, we place estimates on the temperatures and subtypes of both the B stars and RSGs. Overall, we have found 87 new RSG+B star binary systems in M31, M33 and the Small and Large Magellanic Clouds. Our future studies are aimed at determining the binary fraction of RSGs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/366/1230
- Title:
- BI photometry of NGC 1407 and NGC 1400 GCs
- Short Name:
- J/MNRAS/366/1230
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present wide-field Keck telescope imaging of the globular cluster (GC) systems around NGC 1407 and 1400 in the Eridanus galaxy cloud. This is complemented by Hubble Space Telescope (HST) images from the Advanced Camera for Surveys of NGC 1407 and Wide Field and Planetary Camera 2 images of NGC 1400.
- ID:
- ivo://CDS.VizieR/J/ApJS/216/20
- Title:
- Blanco Cosmology Survey (BCS) new reduction
- Short Name:
- J/ApJS/216/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Blanco Cosmology Survey is a four-band (griz) optical-imaging survey of ~80deg^2^ of the southern sky. The survey consists of two fields centered approximately at (RA,DE)=(23h,-55{deg}) and (5h30m,-53{deg}) with imaging sufficient for the detection of L_*_ galaxies at redshift z<=1. In this paper, we present our reduction of the survey data and describe a new technique for the separation of stars and galaxies. We search the calibrated source catalogs for galaxy clusters at z<=0.75 by identifying spatial over-densities of red-sequence galaxies and report the coordinates, redshifts, and optical richnesses, {lambda}, for 764 galaxy clusters at z<=0.75. This sample, >85% of which are new discoveries, has a median redshift of z=0.52 and median richness {lambda}(0.4L_*_)=16.4.
- ID:
- ivo://CDS.VizieR/J/ApJ/742/48
- Title:
- Blanco survey of the lens BCS J2352-5452
- Short Name:
- J/ApJ/742/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the serendipitous discovery in the Blanco Cosmology Survey (BCS) imaging data of a z=0.9057 galaxy that is being strongly lensed by a massive galaxy cluster at a redshift of z=0.3838. The lens (BCS J2352-5452) was discovered while examining i- and z-band images being acquired in 2006 October during a BCS observing run. Follow-up spectroscopic observations with the Gemini Multi-Object Spectrograph instrument on the Gemini-South 8m telescope confirmed the lensing nature of this system. Using weak-plus-strong lensing, velocity dispersion, cluster richness N_200_, and fitting to a Navarro-Frenk-White (NFW) cluster mass density profile, we have made three independent estimates of the mass M_200_ which are all very consistent with each other. The combination of the results from the three methods gives M_200_=(5.1+/-1.3)x10^14^M_{sun}_, which is fully consistent with the individual measurements. The final NFW concentration c_200_ from the combined fit is c_200_=5.4^+1.4^_-1.1_. We have compared our measurements of M_200_ and c_200_ with predictions for (1) clusters from {Lambda}CDM simulations, (2) lensing-selected clusters from simulations, and (3) a real sample of cluster lenses.
- ID:
- ivo://CDS.VizieR/J/A+A/521/A18
- Title:
- Blue stars with disk photometry in NGC 6611
- Short Name:
- J/A+A/521/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 6611 and its parental cloud, the Eagle Nebula (M 16), are well-studied star-forming regions, thanks to their large content of both OB stars and stars with disks and the observed ongoing star formation. In our previous studies of the Eagle Nebula, we identified 834 disk-bearing stars associated with the cloud, after detecting their excesses in NIR bands from J band to 8.0um. In this paper, we study in detail the nature of a subsample of disk-bearing stars that show peculiar characteristics. They appear older than the other members in the V vs. V-I diagram, and/or they have one or more IRAC colors at pure photospheric values, despite showing NIR excesses, when optical and infrared colors are compared.
- ID:
- ivo://CDS.VizieR/J/A+A/463/789
- Title:
- Blue stragglers in open clusters
- Short Name:
- J/A+A/463/789
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of blue-straggler candidates in galactic open clusters. It is based on the inspection of the colour-magnitude diagrams of the clusters, and it updates and supersedes the first version (Ahumada & Lapasset, 1995, Cat. <J/A+AS/109/375>). A new bibliographical search was made for each cluster, and the resulting information is organised into two tables. Some methodological aspects have been revised, in particular those concerning the delimitation of the area in the diagrams where the stragglers are selected. A total of 1887 blue-straggler candidates have been found in 427 open clusters of all ages, doubling the original number. The catalogued stars are classified into two categories mainly according to membership information.
- ID:
- ivo://CDS.VizieR/J/MNRAS/204/151
- Title:
- Bright radio sources at 178 MHz (3CRR)
- Short Name:
- J/MNRAS/204/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A revised sample of bright radio sources at 178MHz is defined in order to correct the biases introduced into the 3CR catalog by confusion and partial resolution. The sample is shown to be 96 percent complete to a flux-density limit of 10Jy for sources smaller than 10arcmin. The bias of the 3CR catalog against objects of larger angular size is also reduced. Optical identifications are presented for 96 percent of the sources, 71 percent with galaxies and 25 percent with quasars. The radio-galaxy population is found to show strong space-density evolution for luminosities in excess of approximately 10^26.5^W/Hz/sr at 178MHz (redshifts greater than or approximately equal to 0.2), while the evolutionary properties of galaxies and quasars of the same luminosity and redshift are very similar.
- ID:
- ivo://CDS.VizieR/J/MNRAS/472/4173
- Title:
- Bright white dwarfs for high-speed photometry
- Short Name:
- J/MNRAS/472/4173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The upcoming NASA Transiting Exoplanet Survey Satellite (TESS) will obtain space-based uninterrupted light curves for a large sample of bright white dwarfs distributed across the entire sky, providing a very rich resource for asteroseismological studies and the search for transits from planetary debris. We have compiled an all-sky catalogue of ultraviolet, optical and infrared photometry as well as proper motions, which we propose as an essential tool for the preliminary identification and characterization of potential targets. We present data for 1864 known white dwarfs and 305 high-probability white dwarf candidates brighter than 17mag. We describe the spectroscopic follow-up of 135 stars, of which 82 are white dwarfs and 25 are hot subdwarfs. The new confirmed stars include six pulsating white dwarf candidates (ZZ Cetis), and nine white dwarf binaries with a cool main- sequence companion. We identify one star with a spectroscopic distance of only 25pc from the Sun. Around the time TESS is launched, we foresee that all white dwarfs in this sample will have trigonometric parallaxes measured by the ESA Gaia mission next year.
- ID:
- ivo://CDS.VizieR/J/AJ/149/111
- Title:
- BRI light curves of 2MASS J02272637+1156494
- Short Name:
- J/AJ/149/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The star 1SWASP J022727.03+115641.7 was reported as a contact binary with a period shorter than the empirical limit of such systems. Our study shows the star not to be variable. Instead, it is the nearby star, 2MASS 02272637+1156494, that exhibits variability. The BRI CCD light curves of 2MASS 02272637+1156494 show the system to be a moderate mass ratio (2.154_-0.074_^+0.008^), and shallow contact (10.4_-1.9_^+1.4^%) W-type contact binary. The masses, radii, and luminosities of the binary components are, respectively, M_1_=0.25_-0.01_^+0.05^M_{sun}_, M_2_=0.54_-0.04_^+0.11^M_{sun}_, R_1_=0.45_-0.01_^+0.02^R_{sun}_, R_2_=0.63_-0.02_^+0.04^R_{sun}_, L_1_=0.038_-0.005_^+0.018^L_{sun}_, and L_2_=0.071_-0.010_^+0.037^L_{sun}_, with an estimated distance 326_-46_^+127^ pc. These uncertainties mainly come from the errors of the colors used to estimate the temperature of the primary star. A dark spot was introduced on the massive component in the final solution.
- ID:
- ivo://CDS.VizieR/J/ApJS/226/17
- Title:
- BRI observations of the QSO Zw III 2
- Short Name:
- J/ApJS/226/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- III Zw 2 is the prototype of radio-intermediate quasars. Although there is the evidence of possessing strong jet, significant {gamma}-ray emission has not been reported before. In this work, we carry out a detailed analysis of the latest Fermi-LAT Pass 8 data. No significant {gamma}-ray signal has been detected in the time-averaged 7-year Fermi-LAT data of III Zw 2; however, we have identified two distinct {gamma}-ray flares with isotropic luminosities of ~10^45^erg/s. Multiwavelength data analysis (also including the optical photometric observations from Yunnan Observatories) are presented and the main finding is simultaneous optical and {gamma}-ray flares of III Zw 2 appearing in 2009 November. Violent {gamma}-ray variability with a doubling timescale of 2.5hr was detected in another {gamma}-ray flare in May 2010, for which the 3-hr {gamma}-ray peak flux is ~250 times of the average flux in 7 years. Rather similar behaviors are observed in blazars and the blazar model can reasonably reproduce the spectral energy distribution of III Zw 2 in a wide energy range, strongly suggesting that its central engine resembles that of blazars. In view of its core, which shares radio similarities with young radio sources, together with weak extended radio lobe emission, we suggest that III Zw 2 harbors a recurrent activity core and thus serves as a valuable target for investigating the fueling and triggering of the activity in radio-loud active galactic nuclei.
- ID:
- ivo://CDS.VizieR/J/A+A/561/L8
- Title:
- BRJK photometry of Seyfert galaxy WPVS48
- Short Name:
- J/A+A/561/L8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using robotic telescopes of the Universitatssternwarte Bochum near Cerro Armazones in Chile, we monitored the z=0.0377 Seyfert 1 galaxy WPVS48 in the optical (B and R) and near-infrared (NIR, J and K) with a cadence of two days.
- ID:
- ivo://CDS.VizieR/J/A+A/579/A113
- Title:
- BR light curves of GJ1214b
- Short Name:
- J/A+A/579/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The atmospheric composition and vertical structure of the super-Earth GJ 1214b has been a subject of debate since its discovery in 2009. Recent studies have indicated that high-altitude clouds might mask the lower layers. However, some data points that were gathered at different times and facilities do not fit this picture, probably because of a combination of stellar activity and systematic errors. We observed two transits of GJ 1214b with the Large Binocular Camera, the dual-channel camera at the Large Binocular Telescope. For the first time, we simultaneously measured the relative planetary radius k=R_p_/R_*_ at blue and red optical wavelengths (B+R), thus constraining the Rayleigh scattering on GJ 1214b after correcting for stellar activity effects. To the same purpose, a long-term photometric follow-up of the host star was carried out with WiFSIP at STELLA, revealing a rotational period that is significantly longer than previously reported. Our new unbiased estimates of k yield a flat transmission spectrum extending to shorter wavelengths, thus confirming the cloudy atmosphere scenario for GJ 1214b.
- ID:
- ivo://CDS.VizieR/J/ApJ/764/5
- Title:
- BR photometry of 2012 precursor flare in OJ287
- Short Name:
- J/ApJ/764/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain the nature of these flares. Precursor flare timings from the historical light curves are compared with theoretical predictions from our model that incorporate effects of an accretion disk and post-Newtonian description for the binary black hole orbit. We find that the precursor flares coincide with the secondary black hole descending toward the accretion disk of the primary black hole from the observed side, with a mean z-component of approximately z_c_=4000AU. We use this model of precursor flares to predict that precursor flare of similar nature should happen around 2020.96 before the next major outburst in 2022.
- ID:
- ivo://CDS.VizieR/J/AJ/136/594
- Title:
- BS Cas BVR light curves
- Short Name:
- J/AJ/136/594
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multicolor charge-coupled device (CCD) photometry for the eclipsing binary BS Cassiopeiae, observed on four nights between 2007 December and 2008 January. Using the Wilson-Devinney program, the photometric solution was derived from our BVR observations. Photometric results indicated that BS Cas is a W-subtype binary, whose mass ratio and overcontact degree are q=0.2834(+/-0.0010) and f=31.6%(+/-1.1%), respectively. Light curves of BS Cas present a typical O'Connell effect, which may be attributed to dark spot activity of the primary component.
- ID:
- ivo://CDS.VizieR/J/A+A/465/943
- Title:
- BVI and RV curves of 5 eclipsing binaries
- Short Name:
- J/A+A/465/943
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We detected tertiary components of close binaries from spectroscopy and light curve modelling, investigated the light-travel time effect and the possibility of magnetic activity cycles, measured mass ratios for unstudied systems, and derived absolute parameters. We carried out new photometric and spectroscopic observations of five bright close eclipsing binaries, predominantly in the southern skies. We obtained full Johnson BV light curves, which were modelled with the Wilson-Devinney code. Radial velocities were measured with the cross-correlation method using IAU radial velocity standards as spectral templates. Period changes were studied with the O-C method, utilising published epochs of minimum light (XY Leo) and ASAS photometry (VZ Lib). For three objects (DX Tuc, QY Hya, V870 Ara), absolute parameters have been determined for the first time. We spectroscopically detected the tertiary components in XY Leo and VZ Lib and discovered one in QY Hya. For XY Leo we updated the light-time effect parameters and detected a secondary periodicity of about 5100d in the O-C diagram that may hint at the existence of short-period magnetic cycles. A combination of recent photometric data shows that the orbital period of the tertiary star in VZ Lib is likely to be over 1500d. QY Hya is a semi-detached X-ray active binary in a triple system with K and M-type components, while V870 Ara is a contact binary with the third smallest spectroscopic mass ratio for a W UMa star to date. Being close to the theoretical minimum for contact binaries, this small mass ratio suggests that V870 Ara has the potential of constraining evolutionary scenarios of binary mergers. The inferred distances to these systems are compatible with the Hipparcos parallaxes.
- ID:
- ivo://CDS.VizieR/J/A+A/478/865
- Title:
- BVIc differential photometry of GSC 0762-110
- Short Name:
- J/A+A/478/865
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometry of the triple-mode radially pulsating variable GSC 0762-0110 has been performed. The star has a fundamental period of 0.1945d and period ratios of 0.7641 and 0.8012. In addition two non-radial modes were found, for which the amplitude diminished considerably over the last few years. The data presented here are the B, V and Ic differential instrumental magnitudes of GSC 0762-0110 with respect to GSC 0766-2426. The V data are from four different observatories, the B and Ic data from a single observatory. Instrumental details are given in the paper.
- ID:
- ivo://CDS.VizieR/J/other/Obs/131.386
- Title:
- BVIc light curves of 8 RR Lyr-type stars
- Short Name:
- J/other/Obs/131.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We took a total of 1175 B, V, and Ic-band CCD frames for 11 GCVS RR Lyr-type variables, for which only the coordinates were known. Observations were made with the 76-crn telescope of the South African Astronomical Observatory. We confirm the variability types, determine the periods, and build the light curves for five objects: BL Aps (P=0.598d), GR Pav (P=0.583d), HI Pav (P=0.643d), HZ Pav (P=0.803d), and IR Pav (P=0.561d). The objects SY Aps (P=0.279d) and IV Pav (P=0.408d) proved to be W UMa-type eclipsing variables; TW Aps (P=0.149d), an SX Phe-type variable; TT Aps (P=482d), an SRD-type semiregular variable, and SW Aps and GI Pav, constant stars.
- ID:
- ivo://CDS.VizieR/J/A+A/539/A139
- Title:
- BVIc light curves of SZ Cam
- Short Name:
- J/A+A/539/A139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic and photometric analysis of the multiple system and early-type eclipsing binary SZ Cam (O9 IV + B0.5 V), which consists of an eclipsing SB2 pair of orbital period P=2.7-days in a long orbit (~55yrs) around a non-eclipsing SB1 pair of orbital period P=2.8-days. We have reconstructed the spectra of the individual components of SZ Cam from the observed composite spectra using the technique of spectral disentangling. We used them together with extensive and accurate BV IC CCD photometry to obtain an orbital solution. Our photometry revealed the presence of a beta Cep variable in the SZ Cam hierarchical system, probably located within the non-eclipsing SB1 pair. The pulsation period is 0.33265+/-0.00005-days and the observed total amplitude in the B band is 0.0105+/-0.0005mag. NLTE analysis of the disentangled spectra provided atmospheric parameters for all three components, consistent with those derived from orbital solution.
- ID:
- ivo://CDS.VizieR/J/AJ/139/2300
- Title:
- BVIc light curves of 3 type II Cepheids
- Short Name:
- J/AJ/139/2300
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Light curves in the B, V, and Ic passbands have been obtained for the type II Cepheids V154 in M3 and V42 and V84 in M5. Alternating cycle behavior, similar to that seen among RV Tauri variables, is confirmed for V84. Old and new observations, spanning more than a century, show that V154 has increased in period while V42 has decreased in period. V84, on the other hand, has shown large, erratic changes in period that do not appear to reflect the long-term evolution of V84 through the Hertzsprung-Russel diagram.
- ID:
- ivo://CDS.VizieR/J/ApJS/137/209
- Title:
- BVIc photoelectric obs. of southern Cepheids
- Short Name:
- J/ApJS/137/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of 2097 photometric observations in the BVI_C_ system are presented for 117 Cepheids located in the southern hemisphere. The main purpose of the photometry is to provide new epochs of maximum brightness for studying Cepheid period changes, as well as to establish current light elements for the Cepheids.
- ID:
- ivo://CDS.VizieR/J/other/NewA/11.262
- Title:
- BVIc photometry in Lynga 11
- Short Name:
- J/other/NewA/11.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained CCD BVI_KC_ photometry down to V~21.5 for the open cluster Lynga 11 and its surrounding field. This previously unstudied object appears to be rich and highly absorbed. A cluster angular radius of 4.5+/-0.5, equivalent to (3.0+/-0.3)pc, is estimated from star counts in 100-pixel a side boxes distributed throughout the whole observed field. Our analysis suggests that Lynga 11 is moderately young and probably of solar metallicity.
- ID:
- ivo://CDS.VizieR/J/AZh/88/886
- Title:
- BVIc photometry of Cepheids from ASAS-3 catalog
- Short Name:
- J/AZh/88/886
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In 2008-2010, we obtained 6095 CCD frames in the BVIc photometric system for 49 classical Cepheids discovered in the ASAS-3 project. The observations were obtained on the 76-cm telescope of the South African Astronomical Observatory (SAAO, RSA) and the 40-cm telescope of the Cerro Armazones Observatory of the Catholic University of the North (OCA, Chile), with a SBIGCCD ST-10XME camera. We present tabulated observations, light curves, and revised elements for the brightness variations.
- ID:
- ivo://CDS.VizieR/J/AJ/140/677
- Title:
- BVIc photometry of IC 4665
- Short Name:
- J/AJ/140/677
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new, BVIc photometric survey of the young open cluster IC 4665, which improves on previous studies of this young cluster by incorporating a rigorous standardization procedure, thus providing high-fidelity colors and magnitudes for cluster members. We use this new photometric dataset to reevaluate the properties (age and distance) of IC 4665.
- ID:
- ivo://CDS.VizieR/J/PASJ/56/295
- Title:
- BVIc photometry of old open clusters
- Short Name:
- J/PASJ/56/295
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric data for 14 galactic open clusters taken by the 65cm telescope at Gunma Astronomical Observatory. They were in the anti-galactic center region selected from the Catalog of Open Cluster Data (Lynga, 1987, See Cat. <J/A+A/438/1163>). We estimated the parameters of the clusters, i.e., age, metallicity, distance, and reddening, by fitting Padova isochrones to the color-magnitude diagram.
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/1482
- Title:
- BVIc photometry of Trumpler 20
- Short Name:
- J/MNRAS/391/1482
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We show that the open cluster Trumpler 20, contrary to the earlier findings, is actually an old Galactic open cluster. New CCD photometry and high-resolution spectroscopy are used to derive the main parameters of this cluster. At [Fe/H]=-0.11 for a single red giant star, the metallicity is slightly subsolar. The best fit to the colour-magnitude diagrams is achieved using a 1.3-Gyr isochrone with convective overshoot. The cluster appears to have a significant reddening at E(B-V)=0.46 (for B0 spectral type), although for red giants this high reddening yields the colour temperature exceeding the spectroscopic Teff by about 200K. Trumpler 20 is a very rich open cluster, containing at least 700 members brighter than M_V_=+4. It may extend over the field of view available in our study at 20x20arcmin^2^.
- ID:
- ivo://CDS.VizieR/J/A+A/417/945
- Title:
- BVI & JHK photometry of NGC 3960
- Short Name:
- J/A+A/417/945
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a BVI photometric and astrometric catalogue of the open cluster NGC 3960, down to limiting magnitude V~22, obtained from observations taken with the Wide Field Imager camera at the MPG/ESO 2.2m Telescope at La Silla. The photometry of all the stars detected in our field of view has been used to estimate a map of the strong differential reddening affecting this area. Our results indicate that, within the region where the cluster dominates, the E(V-I) values range from 0.21 up to 0.78, with E(V-I)=0.36 (E(B-V)=0.29) at the nominal cluster centroid position; color excesses E(V-I) up to 1 mag have been measured in the external regions of the field of view where field stars dominate. The reddening-corrected color-magnitude diagram (CMD) allows us to conclude that the cluster has an age between 0.9 and 1.4Gyr and a distance modulus of (V-M_V)_0=11.35. Based on observations made with the European Southern Observatory telescopes obtained from the the ESO/ST-ECF Science Archive Facility.
- ID:
- ivo://CDS.VizieR/J/A+A/402/425
- Title:
- BVIJHK properties of Single Stellar Populations
- Short Name:
- J/A+A/402/425
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a large grid of photometric properties of single stellar populations that focuses on the near infrared properties of intermediate age populations. The underlying model was presented in recent articles, where we compared its predictions with observations of properties of star clusters and of asymptotic giant branch populations of Local Group galaxies. The grid is made available in tabular form. We present the time evolution of optical and near-infrared broadband colours in the BVIJHK passbands, with ages ranging from 50Myr to 15Gyr, and for initial chemical compositions [Z=0.0004, Y=0.23], [Z=0.004, Y=0.24], [Z=0.008, Y=0.25], [Z=0.02, Y=0.28], and [Z= 0.05, Y=0.352]. The evolution of the stellar mass-to-light ratio in the V and K passbands is also provided. All the stellar models are followed from the zero age main sequence (ZAMS) to the central carbon ignition for massive stars, or to the end of the thermally pulsing regime of the asymptotic giant branch phase (TP-AGB) for low and intermediate mass stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/691/723
- Title:
- BVIJHKs observations of GRB 080319B
- Short Name:
- J/ApJ/691/723
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first gamma-ray burst (GRB) confirmed to be bright enough to be seen with the naked eye, GRB 080319B at redshift z=0.937, allowed for exquisite follow-up observations across the electromagnetic spectrum. We present our detailed optical and infrared (IR) observations of the afterglow, consisting of over 5000 images starting 51s after the GRB trigger, in concert with our own analysis of the Swift UVOT, Burst Alert Telescope (BAT), and XRT data. The event is extreme not only in observed properties but also intrinsically: it was the most luminous event ever recorded at optical and IR wavelengths and had an exceedingly high isotropic-equivalent energy release in {gamma}-rays. At early times, the afterglow evolution is broadly consistent with being reverse-shock dominated, but then is subsumed by a forward shock at around 1000s. The overall spectral energy distribution, spanning from ultraviolet through near-IR wavelengths, shows no evidence for a significant amount of dust extinction in the host frame. The afterglow evolution, however, is highly chromatic: starting at about 1000s the index shifts blueward before shifting back to the red at late times. In our deepest late-time observations, we find tentative evidence for an optical jet break and a luminous supernova. Finally, we examine the detectability of such events with current and future facilities and find that such an event could be detected in gamma rays by BAT out to z=10.7 (8{sigma}), while the nominal EXIST sensitivity would allow detection to z~32. At the K band, this source would have been easily detected with meter-class telescopes to z~17.
- ID:
- ivo://CDS.VizieR/J/AJ/121/768
- Title:
- BVIJH photometry of M82
- Short Name:
- J/AJ/121/768
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution HST imaging in the optical (WFPC2) and near-infrared (NICMOS) of a disk region 1kpc northeast of the starburst core in the nearby galaxy M82.
- ID:
- ivo://CDS.VizieR/J/ApJ/663/277
- Title:
- BVI of NGC 5466 red giants and blue stragglers
- Short Name:
- J/ApJ/663/277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present wide-field BVI photometry for about 11500 stars in the low-metallicity cluster NGC 5466. We have detected the red giant branch bump for the first time, although it is at least 0.2mag fainter than expected relative to the turnoff. The number of red giants (relative to main-sequence turnoff stars) is in excellent agreement with stellar models from the Yonsei-Yale and Teramo groups, and slightly high compared to Victoria-Regina models. This adds to evidence that an abnormally large ratio of red giant to main-sequence stars is not correlated with cluster metallicity.
- ID:
- ivo://CDS.VizieR/J/ApJ/871/33
- Title:
- BVI photometric calatog of star clusters in NGC4589
- Short Name:
- J/ApJ/871/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC4589, a bright E2 merger-remnant galaxy, hosts the peculiar fast and faint calcium-rich supernova SNIb SN2005cz. The progenitor of Ca-rich SNeIb has been controversial: it could be (1) a young, massive star with 6-12M{sun} in a binary system, or (2) an old, low-mass star in a binary system that was kicked out from the galaxy center. Moreover, previous distance estimates for this galaxy have shown a large spread, ranging from 20 to 60Mpc. Thus, using archival Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) F435W, F555W, and F814W images, we search for star clusters in NGC4589 in order to help resolve these issues. We find a small population of young star clusters with 25<V<=27(-7.1<M_V_<-5.1)mag and age <1Gyr in the central region at R<0.5' (<3.8kpc), thus supporting the massive-star progenitor scenario for SN2005cz. In addition to young star clusters, we also find a large population of old globular clusters. In contrast to previous results in the literature, we find that the color distribution of the globular clusters is clearly bimodal. The turnover (Vega) magnitude in the V-band luminosity functions of the blue (metal-poor) globular clusters is determined to be V_0_(max)=24.40{+/-}0.10mag. We derive the total number of globular clusters, N_GC_=640{+/-}50, and the specific frequency, S_N_=1.7{+/-}0.2. Adopting a calibration for the metal-poor globular clusters, M_V_(max) =-7.66{+/-}0.14mag, we derive a distance to this galaxy: (m-M)_0_=32.06{+/-}0.10(ran){+/-}0.15(sys) (d=25.8{+/-}2.2Mpc).
- ID:
- ivo://CDS.VizieR/J/A+A/484/609
- Title:
- BVI photometry and proper motions in M67
- Short Name:
- J/A+A/484/609
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The solar-age open cluster M 67 (C0847+ 120, NGC 2682) is a touchstone in studies of the old Galactic disk. Despite its outstanding role, the census of cluster membership for M 67 at fainter magnitudes and their properties are not well-established. Using proprietary and archival ESO data, we have obtained astrometric, photometric, and radial velocities of stars in a 34x33arcmin^2^ field centered on the old open cluster M 67. The two-epoch archival observations separated by 4-years and acquired with the Wide-Field Imager at the 2.2m MPG/ ESO telescope were reduced with our new astrometric techniques, as described in the first paper in this series (Anderson et al., 2006A&A...454.1029A). The same observations served to derive calibrated BVI photometry in M 67. Radial velocities were measured using the archival and new spectroscopic data obtained at the VLT.
- ID:
- ivo://CDS.VizieR/J/A+A/442/917
- Title:
- BVI photometry in Berkeley 73, 75 and 25
- Short Name:
- J/A+A/442/917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD BVI photometry of the faint open clusters Berkeley 73, Berkeley 75 and Berkeley 25 are presented. The two latter are previously unstudied clusters to our knowledge. While Berkeley 73 is found to be of intermediate-age (about 1.5Gyr old), Berkeley 75 and Berkeley 25 are old clusters, with ages greater than 3.0Gyr. We provide also estimates of the clusters size. All these clusters lie far away from the Galactic Center, at R_GC_>=16kpc, and quite high on the Galactic plane, at |Z_{sun}_|>=1.5kpc. They are therefore important targets to probe the properties of the structure of the Galaxy in this direction, where the Canis Major over-density has been discovered to be located.
- ID:
- ivo://CDS.VizieR/J/MNRAS/344/188
- Title:
- BVI photometry in Fornax cluster galaxies
- Short Name:
- J/MNRAS/344/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVI photometry of 190 galaxies in the central 4x3deg^2^ region of the Fornax cluster observed with the Michigan Curtis Schmidt Telescope. Results from the Fornax Cluster Spectroscopic Survey (FCSS) and the Flair-II Fornax Surveys have been used to confirm the membership status of galaxies in the Fornax Cluster Catalogue (FCC, Cat. <VII/180>). In our catalogue of 213 member galaxies, 92 (43 per cent) have confirmed radial velocities.
- ID:
- ivo://CDS.VizieR/J/AJ/134/825
- Title:
- BVI photometry in M55 (NGC 6809)
- Short Name:
- J/AJ/134/825
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled the asymptotic giant, horizontal, and upper red giant branch (AGB, HB, and RGB) stars in the globular cluster M55 (NGC 6809). Using the star counts and the R-parameter we compute the initial helium abundance Y=0.274+/-0.016.
- ID:
- ivo://CDS.VizieR/J/A+A/462/245
- Title:
- BVI photometry in NGC 6611
- Short Name:
- J/A+A/462/245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observation of young stars with circumstellar disks suggests that the disks are dissipated, starting from the inner region, by the radiation of the central star and eventually by the formation of rocky planetesimals, over a time scale of several million years. It was also shown that strong UV radiation emitted by nearby massive stars can heat a circumstellar disk up to some thousand degrees, inducing the photoevaporation of the gas. This process strongly reduces the dissipation time scale. We study whether there exists a correlation between the spatial distribution of stars with circumstellar disks and the position of massive stars with spectral class earlier than B5, in the open cluster NGC 6611. We created a multiband catalog of the cluster, down to V~23mag, using optical data from a WFI observation at 2.2m of ESO in the BVI bands, the 2MASS public point source catalog and an archival X-ray observation made with CHANDRA/ACIS. We selected the stars with infrared excess (due to the emission of a circumstellar disk) using suitable color indices independent of extinction, and studied their spatial distribution.