- ID:
- ivo://CDS.VizieR/J/ApJ/752/61
- Title:
- Blazars in unidentified {gamma}-ray sources
- Short Name:
- J/ApJ/752/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the main scientific objectives of the ongoing Fermi mission is unveiling the nature of unidentified {gamma}-ray sources (UGSs). Despite the major improvements of Fermi in the localization of {gamma}-ray sources with respect to the past {gamma}-ray missions, about one-third of the Fermi-detected objects are still not associated with low-energy counterparts. Recently, using the Wide-field Infrared Survey Explorer survey, we discovered that blazars, the rarest class of active galactic nuclei and the largest population of {gamma}-ray sources, can be recognized and separated from other extragalactic sources on the basis of their infrared (IR) colors. Based on this result, we designed an association method for the {gamma}-ray sources to recognize if there is a blazar candidate within the positional uncertainty region of a generic {gamma}-ray source. With this new IR diagnostic tool, we searched for {gamma}-ray blazar candidates associated with the UGS sample of the second Fermi {gamma}-ray LAT catalog (2FGL). We found that our method associates at least one {gamma}-ray blazar candidate as a counterpart to each of 156 out of 313 UGSs analyzed. These new low-energy candidates have the same IR properties as the blazars associated with {gamma}-ray sources in the 2FGL catalog.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/206/12
- Title:
- Blazars with {gamma}-ray counterparts. I.
- Short Name:
- J/ApJS/206/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new method for identifying blazar candidates by examining the locus, i.e., the region occupied by the Fermi {gamma}-ray blazars in the three-dimensional color space defined by the WISE infrared colors. This method is a refinement of our previous approach that made use of the two-dimensional projection of the distribution of WISE {gamma}-ray-emitting blazars (the Strip) in the three WISE color-color planes. In this paper, we define the three-dimensional locus by means of a principal component analysis of the color distribution of a large sample of blazars composed of all the ROMA-BZCAT sources with counterparts in the WISE All-Sky Catalog associated with {gamma}-ray sources in the second Fermi-LAT catalog (2FGL; the WISE Fermi blazars sample, WFB). Our new procedure yields a total completeness of c_tot_~81% and a total efficiency of e_tot_~97%. We also obtain local estimates of the efficiency and completeness as functions of the WISE colors and galactic coordinates of the candidate blazars. The catalog of all WISE candidate blazars associated with the WFB sample is also presented, complemented by archival multi-frequency information for the alternative associations. Finally, we apply the new association procedure to all {gamma}-ray blazars in the 2FGL and provide a catalog containing all the {gamma}-ray candidate blazars selected according to our procedure.
- ID:
- ivo://CDS.VizieR/J/ApJS/206/13
- Title:
- Blazars with {gamma}-ray counterparts. II.
- Short Name:
- J/ApJS/206/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A significant fraction (~30%) of the high-energy gamma-ray sources listed in the second Fermi Large Area Telescope catalog (2FGL) are still of unknown origin, being not yet associated with counterparts at low energies. We recently developed a new association method to identify if there is a {gamma}-ray blazar candidate within the positional uncertainty region of a generic 2FGL source. This method is entirely based on the discovery that blazars have distinct infrared colors with respect to other extragalactic sources found, thanks to the Wide-field Infrared Survey Explorer (WISE) all-sky observations. Several improvements have also been performed to increase the efficiency of our method in recognizing {gamma}-ray blazar candidates. In this paper we applied our method to two different samples, the first constituted by unidentified {gamma}-ray sources (UGSs), and the second by active galaxies of uncertain type, both listed in the 2FGL. We present a catalog of IR counterparts for ~20% of the UGSs investigated. Then, we also compare our results for the associated sources with those present in the literature. In addition, we illustrate the extensive archival research carried out to identify the radio, infrared, optical, and X-ray counterparts of the WISE-selected, {gamma}-ray blazar candidates. Finally, we discuss the future developments of our method based on ground-based follow-up observations.
- ID:
- ivo://CDS.VizieR/J/ApJS/207/16
- Title:
- BL Lac candidates for TeV observations
- Short Name:
- J/ApJS/207/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BL Lac objects are the most numerous class of extragalactic TeV-detected sources. One of the biggest difficulties in investigating their TeV emission is due to their limited number, since only 47 BL Lac objects are known to be TeV emitters. In this paper, we propose new criteria to select TeV BL Lac candidates based on infrared and X-ray observations. We apply our selection criteria to the BL Lac objects listed in the ROMA-BZCAT catalog (Cat. J/A+A/495/691), thereby identifying 41 potential TeV emitters. We then perform a search over a more extended sample combining the ROSAT bright source catalog (Cat. IX/10) and the WISE all-sky survey (Cat. II/311), revealing 54 additional candidates for TeV observations. Our investigation also led to a tentative classification of 16 unidentified X-ray sources as BL Lac candidates. This analysis provides new interesting BL Lac targets for future observations with ground-based Cherenkov telescopes.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A26
- Title:
- BL Lac objects beyond z=1.3
- Short Name:
- J/A+A/538/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of the {gamma}-ray sky with Fermi led to significant advances towards understanding blazars, the most extreme class of active galactic nuclei. A large fraction of the population detected by Fermi is formed by BL Lacertae (BL Lac) objects, whose sample has always suffered from a severe redshift incompleteness due to the quasi-featureless optical spectra. Our goal is to provide a significant increase of the number of confirmed high-redshift BL Lac objects contained in the 2 LAC Fermi/LAT catalog.
- 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/AJ/152/16
- Title:
- Bolometric flux estimation for cool evolved stars
- Short Name:
- J/AJ/152/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Estimation of bolometric fluxes (F_BOL_) is an essential component of stellar effective temperature determination with optical and near-infrared interferometry. Reliable estimation of F_BOL_ simply from broadband K-band photometry data is a useful tool in those cases were contemporaneous and/or wide-range photometry is unavailable for a detailed spectral energy distribution (SED) fit, as was demonstrated in Dyck et al. Recalibrating the intrinsic F_BOL_ versus observed F_2.2{mu}m_ relationship of that study with modern SED fitting routines, which incorporate the significantly non-blackbody, empirical spectral templates of the INGS spectral library (an update of the library in Pickles) and estimation of reddening, serves to greatly improve the accuracy and observational utility of this relationship. We find that F_BOL_ values predicted are roughly 11% less than the corresponding values predicted in Dyck et al., indicating the effects of SED absorption features across bolometric flux curves.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/629
- Title:
- Bootes-HiZELS. Em-line galaxies at z=0.4-4.7
- Short Name:
- J/MNRAS/471/629
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of ~1000 emission-line galaxies at z=0.4-4.7 from the ~0.7deg^2^ High-z Emission-Line Survey in the Bootes field identified with a suite of six narrow-band filters at ~=0.4-2.1{mu}m. These galaxies have been selected on their Ly{alpha} (73), [OII] (285), H{beta}/[OIII] (387) or H{alpha} (362) emission line, and have been classified with optical to near-infrared colours. A subsample of 98 sources have reliable redshifts from multiple narrow-band (e.g. [OII]-H{alpha}) detections and/or spectroscopy. In this survey paper, we present the observations, selection and catalogues of emitters. We measure number densities of Ly{alpha}, [OII], H{beta}/[OIII] and H{alpha} and confirm strong luminosity evolution in star-forming galaxies from z~0.4 to ~5, in agreement with previous results. To demonstrate the usefulness of dual-line emitters, we use the sample of dual [OII]-H{alpha} emitters to measure the observed [OII]/H{alpha} ratio at z=1.47. The observed [OII]/H{alpha} ratio increases significantly from 0.40+/-0.01 at z=0.1 to 0.52+/-0.05 at z=1.47, which we attribute to either decreasing dust attenuation with redshift, or due to a bias in the (typically) fibre measurements in the local Universe that only measure the central kpc regions. At the bright end, we find that both the H{alpha} and Ly{alpha} number densities at z~=2.2 deviate significantly from a Schechter form, following a power law. We show that this is driven entirely by an increasing X-ray/active galactic nucleus fraction with line luminosity, which reaches ~=100 per cent at line luminosities L>=3x10^44^erg/s.
- ID:
- ivo://CDS.VizieR/J/ApJ/853/47
- Title:
- Brightest cluster galaxies bright in 22um (W4BCGs)
- Short Name:
- J/ApJ/853/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Brightest cluster galaxies (BCGs) are believed to have assembled most of their stars early in time and therefore should be passively evolving at low redshifts and appear "red-and-dead." However, there have been reports that a minority of low-redshift BCGs still have ongoing star formation rates (SFRs) of a few to even ~100M_{sun}_/yr. Such BCGs are found in "cool-core" ("CC") clusters, and their star formation is thought to be fueled by "cooling flow." To further investigate the implications of low-redshift, star-forming BCGs, we perform a systematic search using the 22{mu}m data ("W4" band) from the Wide-field Infrared Survey Explorer (WISE) on the GMBCG catalog, which contains 55424 BCGs at 0.1<~z<~0.55 identified in the Sloan Digital Sky Survey (SDSS). Our sample consists of 389 BCGs that are bright in W4 ("W4BCGs"), most being brighter than 5mJy. While some (<~20%) might host active galactic nuclei, most W4BCGs should owe their strong mid-IR emissions to dust-enshrouded star formation. Their median total IR luminosity (L_IR_) is 5x10^11^L_{sun}_ (SFR~50M_{sun}_/yr), and 27% of the whole sample has L_IR_>10^12^L_{sun}_ (SFR>100M_{sun}_/yr). Using 10 W4BCGs that have Chandra X-ray data, we show that 7 of them are possibly in CC clusters. However, in most cases (five out of seven) the mass deposition rate cannot account for the observed SFR. This casts doubt on the idea that cooling flows are the cause of the star formation in non-quiescent BCGs.
- ID:
- ivo://CDS.VizieR/J/A+A/466/917
- Title:
- Brightest stars of sigma Orionis cluster
- Short Name:
- J/A+A/466/917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The very young sigma Orionis cluster (about 3Ma) is a cornerstone for the understanding of the formation of stars and substellar objects down to planetary masses. However, its stellar population is far to be completely known. This study has the purpose of identifying and characterising the most massive stars of sigma Orionis to complement current and future deep searches for brown dwarfs and planetary-mass objects in the cluster. I have cross-correlated the sources in the Tycho and 2MASS catalogues in a region of 30arcmin radius with centre in the O-type star sigma Ori A. In the area, I have studied the membership in the Ori OB 1b Association of the brightest stars in the optical using astrometric, X-ray and infrared and optical photometric data from public catalogues and spectroscopic data from the literature. A list of 26 young stars, four candidate young stars and 16 probable foreground stars has arised from the study. Seven young stars probably harbour discs (four are new). There is no mass-dependence of the disc frequency in the cluster. I have derived for the first time the mass spectrum in sigma Orionis from 1.1 to 24M_{sun}_ (alpha=+2.0^+0.2^_-0.1_; roughly Salpeter-like). I have also provided additional proofs on the existence of several spatially superimposed stellar populations in the direction of sigma Orionis. Finally, the cluster may be closer and older than previously considered.
- ID:
- ivo://CDS.VizieR/J/ApJ/902/127
- Title:
- Bright Gaia white dwarfs with unWISE photometry
- Short Name:
- J/ApJ/902/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Studies of excess infrared radiation around white dwarfs provide important constraints on the evolution of planetary systems and low-mass companions beyond the main-sequence stage. In this paper series, we focus on identifying and characterizing bright white dwarfs with an infrared excess. Here, we present 188 infrared excess candidates from Gaia and unWISE, 147 of which are new discoveries. Further characterization of this sample can significantly increase the current list of white dwarf debris disks and white dwarfs with low-mass companions.
- ID:
- ivo://CDS.VizieR/J/AJ/138/251
- Title:
- Bright Galactic stars with 24um excesses
- Short Name:
- J/AJ/138/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optically bright Galactic stars (V<~13mag) having f_nu_(24um)>1mJy are identified in Spitzer mid-infrared surveys within 8.2deg^2^ for the Bootes field of the NOAO Deep Wide-Field Survey and within 5.5deg^2^ for the First Look Survey (FLS). One hundred and twenty-eight stars are identified in Bootes and 140 in the FLS, and their photometry is given. (K-[24]) colors are determined using K magnitudes from the Two Micron All Sky Survey for all stars in order to search for excess 24um luminosity compared to that arising from the stellar photosphere.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/81
- Title:
- Bright metal-poor stars from HES Survey. II.
- Short Name:
- J/ApJ/835/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtain estimates of stellar atmospheric parameters for a previously published sample of 1777 relatively bright (9<B<14) metal-poor candidates from the Hamburg/ESO Survey. The original Frebel+ (2006, J/ApJ/652/1585; Paper I) analysis of these stars was able to derive estimates of [Fe/H] and [C/Fe] only for a subset of the sample, due to limitations in the methodology then available. A new spectroscopic analysis pipeline has been used to obtain estimates of T_eff_, logg, [Fe/H], and [C/Fe] for almost the entire data set. This sample is very local-about 90% of the stars are located within 0.5kpc of the Sun. We consider the chemodynamical properties of these stars in concert with a similarly local sample of stars from a recent analysis of the Bidelman and MacConnell "weak metal" candidates by Beers+ (2014, J/ApJ/794/58). We use this combined sample to identify possible members of the halo stream of stars suggested by Helmi+ (1999Natur.402...53H) and Chiba & Beers (2000AJ....119.2843C), as well as stars that may be associated with stripped debris from the putative parent dwarf of the globular cluster Omega Centauri, suggested to exist by previous authors. We identify a clear increase in the cumulative frequency of carbon-enhanced metal-poor (CEMP) stars with declining metallicity, as well as an increase in the fraction of CEMP stars with distance from the Galactic plane, consistent with previous results. We also identify a relatively large number of CEMP stars with kinematics consistent with the metal-weak thick-disk population, with possible implications for its origin.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/268
- Title:
- Bright QSOs in Southern Hemisphere (QUBRICS)
- Short Name:
- J/ApJ/887/268
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of absorptions along the lines of sight to bright high-z QSOs is an invaluable cosmological tool that provides a wealth of information on the inter-/circum-galactic medium, dark matter, primordial elements, reionization, fundamental constants, and general relativity. Unfortunately, the number of bright (i<~18) QSOs at z>~2 in the southern hemisphere is much lower than that in the north, due to the lack of wide multiwavelength surveys at decl. {delta}<0{deg}, hampering the effectiveness of observations from southern observatories. In this work we present a new method based on Canonical Correlation Analysis to identify such objects, taking advantage of a number of available databases: Skymapper, Gaia DR2, WISE, and 2MASS. Our QSO candidate sample lists 1476 sources with i<18 over 12400deg^2^ in the southern hemisphere. With a preliminary campaign we observed spectroscopically 69 of them, confirming 54 new bright QSOs at z>2.5, corresponding to a success rate of our method of ~80%. Furthermore, we estimate a completeness of ~90% of our sample at completion of our observation campaign. The new QSOs confirmed by this first and the forthcoming campaigns (QUBRICS survey) will be the targets of subsequent studies using higher resolution spectrographs, like ESPRESSO, UVES, and (in the long term) ELT/HIRES.
- 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/A+A/416/555
- Title:
- Brown Dwarfs in ChaI Dark Cloud
- Short Name:
- J/A+A/416/555
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a multiband survey for brown dwarfs in the Chamaeleon I dark cloud with the Wide Field Imager (WFI) camera at the ESO/MPG 2.2-m telescope on La Silla (Chile) on 28-May to 03-Jun 1999. The survey has revealed a substantial population of brown dwarfs in this southern star-forming region. Candidates were selected from R, I and H{alpha} imaging observations. We also observed in two medium-band filters, M855 and M915, for spectral type determination. The former filter covers a wavelength range containing spectral features characteristic of M-dwarfs, while the latter lies in a relatively featureless wavelength region for these late-type objects. A correlation was found between spectral type and (M855-M915) colour index for mid- to late M-type objects and early L-type dwarfs. With this method, we identify most of our object candidates as being of spectral type M5 or later. Our results show that there is no strong drop in the number of objects for the latest spectral types, hence brown dwarfs may be as abundant as low-mass stars in this region. Also, both kind of objects have a similar spatial distribution. We derive an index {alpha}=0.6+/-0.1 of the mass function in this region of dispersed star formation, in good agreement with the values obtained in other star forming regions and young clusters. Some of the brown dwarfs have strong H{alpha} emission, suggesting mass accretion. For objects with published infrared photometry, we find that strong H{alpha} emission is related to a mid-infrared excess, indicative of the existence of a circumstellar disk.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2856
- Title:
- Brown dwarfs in the 2MASS Survey
- Short Name:
- J/AJ/127/2856
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of seven new T dwarfs identified in the Two Micron All Sky Survey (Cat. <II/246>). Low-resolution (R~150) 0.8-2.5{mu}m spectroscopy obtained with the Infrared Telescope Facility (IRTF) SpeX instrument reveals the characteristic H_2_O and CH_4_ bands in the spectra of these brown dwarfs. Comparison with spectral standards observed with the same instrument enables us to derive classifications of T3 to T7 for the objects in this sample. Moderate-resolution (R~1200) near-infrared spectroscopy for a subset of these discoveries reveal K I line strengths consistent with previously observed trends with spectral type. Follow-up imaging observations provide proper-motion measurements for these sources, ranging from less than 0.1" to 1.55"/yr. One object, 2MASS 0034+0523, has a spectrophotometric distance placing it within 10pc of the Sun. This source also exhibits a depressed K-band peak reminiscent of the peculiar T dwarf 2MASS 0937+2931 and may be a metal-poor or old, high-mass brown dwarf. We also present low-resolution SpeX data for a set of M- and L-type dwarf, subdwarf, and giant comparison stars used to classify 59 additional candidates identified as background stars. These are primarily M5-M8.5 dwarfs, many exhibiting H I Pa^{gamma}^, but include three candidate ultracool M subdwarfs and one possible early-type L subdwarf.
- ID:
- ivo://CDS.VizieR/J/ApJ/842/118
- Title:
- Brown dwarfs with spectral type later than T6
- Short Name:
- J/ApJ/842/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The survey of the mid-infrared sky by the Wide-field Infrared Survey Explorer (WISE) led to the discovery of extremely cold, low-mass brown dwarfs, classified as Y dwarfs, which extend the T class to lower temperatures. Twenty-four Y dwarfs are known at the time of writing. Here we present improved parallaxes for four of these, determined using Spitzer images. We give new photometry for four late-type T and three Y dwarfs and new spectra of three Y dwarfs, obtained at Gemini Observatory. We also present previously unpublished photometry taken from HST, ESO, Spitzer, and WISE archives of 11 late-type T and 9 Y dwarfs. The near-infrared data are put onto the same photometric system, forming a homogeneous data set for the coolest brown dwarfs. We compare recent models to our photometric and spectroscopic data set. We confirm that nonequilibrium atmospheric chemistry is important for these objects. Nonequilibrium cloud-free models reproduce well the near-infrared spectra and mid-infrared photometry for the warmer Y dwarfs with 425<=T_eff_(K)<=450. A small amount of cloud cover may improve the model fits in the near-infrared for the Y dwarfs with 325<=T_eff_(K)<=375. Neither cloudy nor cloud-free models reproduce the near-infrared photometry for the T_eff_=250K Y dwarf WISEJ085510.83-071442.5 (W0855). We use the mid-infrared region, where most of the flux originates, to constrain our models of W0855. We find that W0855 likely has a mass of 1.5-8 Jupiter masses and an age of 0.3-6Gyr. The Y dwarfs with measured parallaxes are within 20pc of the Sun and have tangential velocities typical of the thin disk. The metallicities and ages we derive for the sample are generally solar-like. We estimate that the known Y dwarfs are 3 to 20 Jupiter-mass objects with ages of 0.6-8.5Gyr.
- 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/ApJ/821/L25
- Title:
- Bulge RR Lyrae Radial Velocity Assay (BRAVA-RR)
- Short Name:
- J/ApJ/821/L25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 947 radial velocities of RR Lyrae variable stars in four fields located toward the Galactic bulge, observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay (BRAVA-RR). We show that these RR Lyrae stars (RRLs) exhibit hot kinematics and null or negligible rotation and are therefore members of a separate population from the bar/pseudobulge that currently dominates the mass and luminosity of the inner Galaxy. Our RRLs predate these structures and have metallicities, kinematics, and spatial distribution that are consistent with a "classical" bulge, although we cannot yet completely rule out the possibility that they are the metal-poor tail of a more metal-rich ([Fe/H]~-1dex) halo-bulge population.
- ID:
- ivo://CDS.VizieR/J/other/ApSS/363.127
- Title:
- Bulge RR Lyrae VVVDR4 photometry
- Short Name:
- J/other/ApSS/363
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This study's objective was to exploit infrared VVV (VISTA Variables in the Via Lactea) photometry for high latitude RRab stars to establish an accurate Galactic Centre distance. RRab candidates were discovered and reaffirmed (n=4194) by matching Ks photometry with templates via chisq minimization, and contaminants were reduced by ensuring targets adhered to a strict period-amplitude (Ks) trend and passed the Elorietta et al. (2016A&A...595A..82E) classifier. The distance to the Galactic Centre was determined from a high latitude Bulge subsample (|b|>4, RGC=8.30+/-0.36kpc, random uncertainty is relatively negligible), and importantly, the comparatively low color-excess and uncrowded location mitigated uncertainties tied to the extinction law, the magnitude-limited nature of the analysis, and photometric contamination. Circumventing those problems resulted in a key uncertainty being the MKs relation, which was derived using LMC RRab stars (MKs=-(2.66+/-0.06)logP-(1.03+/-0.06), (J-Ks)0=(0.31+/-0.04)logP +(0.35+/-0.02), assuming mu0LMC=18.43). The Galactic Centre distance was not corrected for the cone-effect. Lastly, a new distance indicator emerged as brighter overdensities in the period-magnitude-amplitude diagrams analyzed, which arise from blended RRab and red clump stars. Blending may thrust faint extragalactic variables into the range of detectability.
- ID:
- ivo://CDS.VizieR/J/ApJ/716/942
- Title:
- Bulges of nearby galaxies with Spitzer
- Short Name:
- J/ApJ/716/942
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate scaling relations of bulges using bulge-disk decompositions at 3.6um and present bulge classifications for 173 E-Sd galaxies within 20Mpc. Pseudobulges and classical bulges are identified using Sersic index, Hubble Space Telescope morphology, and star formation activity (traced by 8um emission). In the near-IR pseudobulges have n_b_<2 and classical bulges have n_b_>2, as found in the optical. Sersic index and morphology are essentially equivalent properties for bulge classification purposes. We confirm, using a much more robust sample, that the Sersic index of pseudobulges is uncorrelated with other bulge structural properties, unlike for classical bulges and elliptical galaxies. Also, the half-light radius of pseudobulges is not correlated with any other bulge property. We also find a new correlation between surface brightness and pseudobulge luminosity; pseudobulges become more luminous as they become more dense.
- 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/MNRAS/355/1272
- Title:
- BVIJHKs photometry around CG 12
- Short Name:
- J/MNRAS/355/1272
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A method for determining distances to dark clouds and Bok globules based on broad-band optical and near-infrared photometry is presented. In this method, intrinsic colour indices of stars projected towards the direction of a cloud are computed by dereddening the observed colour indices using various trial values of extinction A_V_ and a standard extinction law. The computed intrinsic colour indices for a star are then compared with the intrinsic colour indices of normal main-sequence stars and a spectral type is assigned to the star for which the computed colour indices best match the standard intrinsic colour indices. Distances (d) to the stars are determined using the A_V_ and absolute magnitudes (M_V_) corresponding to the spectral types thus obtained. A plot of A_V_ against d undergoes a sharp rise at a distance corresponding to the distance to the cloud. Using this method, we have determined a distance of 550pc to the cometary globule CG 12.
- 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.