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4991. Photometric survey for M33 stellar clusters
ID:
ivo://CDS.VizieR/J/AcA/58/23
Title:
Photometric survey for M33 stellar clusters
Short Name:
J/AcA/58/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 4780 extended sources from the outer field of M33. The catalog includes 73 previously identified clusters or planetary nebulae, 1153 likely background galaxies, and 3554 new candidate stellar clusters. The survey is based on deep ground-based images obtained with the MegaCam instrument on the CFHT telescope. We provide g'r'i' photometry for detected objects as well as estimates of the FWHM and ellipticity of their profiles. The sample includes 122 new, relatively bright, likely globular clusters. Follow-up observations of fainter candidates from our list may extend the faint-end of the observed luminosity function of globular clusters in M33 by up to 3 magnitudes. The catalog includes several cluster candidates located in the outskirts of the galaxy. These objects are promising targets for deep photometry with the HST. We present a color-magnitude diagram for one detected object, showing that it is an extended and low-surface-brightness old cluster located at an angular distance of 27' from the center of M33.
4992. Photometric survey of MS 1054-03 field
ID:
ivo://CDS.VizieR/J/AJ/131/1891
Title:
Photometric survey of MS 1054-03 field
Short Name:
J/AJ/131/1891
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present deep near-infrared Js-, H-, and Ks-band imaging of a field around MS 1054-03, a massive cluster at z=0.83. The observations were carried out with the ISAAC instrument at the ESO Very Large Telescope (VLT) as part of the Faint Infrared Extragalactic Survey (FIRES). The total integration time amounts to 25.9hr in Js, 24.4hr in H, and 26.5hr in Ks, divided nearly equally between four pointings covering 5.5'x5.3'. The 3 total limiting AB magnitudes for point sources from the shallowest to the deepest pointing are J^tot^_s,AB_=26.0-26.2, H^tot^_AB_=25.5-25.8, and K^tot^_s,AB_=25.3-25.7mag. The effective spatial resolution of the co-added images has FWHM=0.48", 0.46", and 0.52" in Js, H, and Ks, respectively. We complemented the ISAAC data with deep optical imaging using existing Hubble Space Telescope WFPC2 mosaics through the F606W and F814W filters and additional U-, B-, and V-band observations we obtained with the VLT FORS1 instrument. We constructed a Ks-band-limited multicolor source catalog down to K^tot^_s,AB_~25mag (~5{sigma} for point sources). The catalog contains 1858 objects, of which 1663 have eight-band photometry. We describe the observations, data reduction, source detection, and photometric measurements method. We also present the number counts, color distributions, and photometric redshifts zph of the catalog sources. We find that our Ks-band counts at the faint end 22<~K_s,AB_<~25, with slope dlogN/dm=0.20, lie at the flatter end of published counts in other deep fields and are consistent with those we derived previously in the Hubble Deep Field-South (HDF-S), the other FIRES field. Spectroscopic redshifts zsp are available for ~330 sources in the MS 1054-03 field; comparison between zph and zsp shows very good agreement, with <|zsp-zph|/(1+zsp)>=0.078. The MS 1054-03 field observations complement our HDF-S data set with a nearly 5 times larger area at ~0.7mag brighter limits, providing more robust statistics for the slightly brighter source populations.
4993. Photometric survey of planetary nebulae in M31
ID:
ivo://CDS.VizieR/J/ApJ/792/121
Title:
Photometric survey of planetary nebulae in M31
Short Name:
J/ApJ/792/121
Date:
21 Oct 2021
Publisher:
CDS
Description:
We search the Hubble Space Telescope (HST) Advanced Camera for Surveys and Wide Field Camera 3 broadband imaging data from the Panchromatic Hubble Andromeda Treasury (PHAT) survey to identify detections of cataloged planetary nebulae (PNs). Of the 711 PNs currently in the literature within the PHAT footprint, we find 467 detected in the broadband. For these 467, we are able to refine their astrometric accuracy from ~0.3'' to 0.05''. Using the resolution of the HST, we are able to show that 152 objects currently in the catalogs are definitively not PNs, and we show that 32 objects thought to be extended in ground-based images are actually point-like and therefore good PN candidates. We also find one PN candidate that is marginally resolved. If this is a PN, it is up to 0.7 pc in diameter. With our new photometric data, we develop a method of measuring the level of excitation in individual PNs by comparing broadband and narrowband imaging and describe the effects of excitation on a PN's photometric signature. Using the photometric properties of the known PNs in the PHAT catalogs, we search for more PNs, but do not find any new candidates, suggesting that ground-based emission-line surveys are complete in the PHAT footprint to F475W =~ 24.
4994. Photometric variability of BeSS-KELT stars
ID:
ivo://CDS.VizieR/J/AJ/153/252
Title:
Photometric variability of BeSS-KELT stars
Short Name:
J/AJ/153/252
Date:
21 Oct 2021
Publisher:
CDS
Description:
Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, a baseline of up to 10 years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the northern and southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long-term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-types. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectra database allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.
4995. Photometric Variability of HD 51585
ID:
ivo://CDS.VizieR/J/PAZh/32/662
Title:
Photometric Variability of HD 51585
Short Name:
J/PAZh/32/662
Date:
21 Oct 2021
Publisher:
CDS
Description:
Photoelectric observations of HD 51585 (OY Gem), a B[e] star with an infrared excess and a candidate for protoplanetary nebulae, obtained with a 60-cm telescope at the Crimean Station of the Sternberg Astronomical Institute in 1992-2005 are presented. The star exhibited rapid irregular brightness variations with amplitudes from 0.1mag in the V band to 0.2mag in the U band within the observing season as well as slow systematic variations with amplitudes from 0.3mag in the V band to 0.65mag in the U band and with a quasi-period of ~2800days. The B-V color index varied within 0.1mag and did not follow the slow systematic brightness variations, while U-B correlated with the U brightness and varied between 0.7mag at maximum light and 0.35mag at minimum light. Our low-resolution spectroscopy performed in 1994-2005 has revealed significant variability of the Balmer and Paschen hydrogen emission lines as well as the He I and OI lines. Equivalent widths are given for the HI, He I, OI, and Fe II lines; a correlation has been found between the star's photometric variability and the hydrogen line intensities. Our joint analysis of the photometric and spectroscopic data suggests that variations in a strong stellar wind are responsible for the variability of the star.
4996. Photometric variability of WR 103
ID:
ivo://CDS.VizieR/J/other/ApSS/345.133
Title:
Photometric variability of WR 103
Short Name:
J/other/ApSS/345
Date:
21 Oct 2021
Publisher:
CDS
Description:
We discuss a collection of archival multi-colour photometric data of the variable WC9-type Wolf-Rayet star WR103=HD164270 observed over a time interval of eleven years. The photometric systems used are Walraven VBLUW, Bessel UBV and Stromgren uvby. The purpose is to search for periodicity and to disentangle continuum and line emission variations.
4997. Photometric variability search in the CSTAR field
ID:
ivo://CDS.VizieR/J/ApJS/218/20
Title:
Photometric variability search in the CSTAR field
Short Name:
J/ApJS/218/20
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Chinese Small Telescope Array (CSTAR) is the first telescope facility built at Dome A, Antarctica. During the 2008 observing season, the installation provided long-baseline and high-cadence photometric observations in the i-band for 18145 targets within 20deg^2^ CSTAR field around the South Celestial Pole for the purpose of monitoring the astronomical observing quality of Dome A and detecting various types of photometric variability. Using sensitive and robust detection methods, we discover 274 potential variables from this data set, 83 of which are new discoveries. We characterize most of them, providing the periods, amplitudes, and classes of variability.
4998. Photometric variations of Eris (136199)
ID:
ivo://CDS.VizieR/J/A+A/479/877
Title:
Photometric variations of Eris (136199)
Short Name:
J/A+A/479/877
Date:
21 Oct 2021
Publisher:
CDS
Description:
Eris is the largest dwarf planet currently known in the solar system. Knowled ge about its physical parameters is necessary to interpret the characteristics of these kinds of bodies. The goal of this work is to study Eris' short-term and long-term variability in order to determine the amplitude of the light-curve, which can be linked to the degree of elongation of the body or to the degree of albedo heterogeneity on the surface of the dwarf planet. In addition, the rotation period can be determined. CCD photometric observations of the trans Neptunian object Eris in R band on 16 nights spanning two years were carried out using the 1.5m telescope at Sierra Nevada Observatory (OSN), the 2.5m Isaac Newton Telescope (INT) telescope at the Roque de los Muchachos Observatory, and the 2.2m Telescope at Calar Alto Observatory. The time-series analysis leads to indications of a short-term variability whose nature is not clear. It could be real or a result of data-reduction artifacts, such as contamination by close, faint-background stars. The most significant periodicities are 14h or its double, but other possibilities cannot be ruled out, like a 32h weaker peak in the periodogram. As for the amplitude of the light-curve, we get a peak-to-peak variability of 0.01+/-0.01mag. The study of the long-term variability indicates that a long rotation period cannot be rejected, but the amplitude would be smaller than 0.06mag. These results are compatible with a nearly spherical body that has a homogeneous surface.
4999. Photometry and abundances of NGC1851 stars
ID:
ivo://CDS.VizieR/J/MNRAS/442/3044
Title:
Photometry and abundances of NGC1851 stars
Short Name:
J/MNRAS/442/3044
Date:
21 Oct 2021
Publisher:
CDS
Description:
NGC 1851 is surrounded by a stellar component that extends more than 10 times beyond the tidal radius. Although the nature of this stellar structure is not known, it has been suggested to be a sparse halo of stars or associated with a stellar stream. We analyse the nature of this intriguing stellar component surrounding NGC 1851 by investigating its radial velocities and chemical composition, in particular in comparison with those of the central cluster analysed in a homogeneous manner. In total we observed 23 stars in the halo with radial velocities consistent with NGC 1851, and for 15 of them we infer [Fe/H] abundances. Our results show that (i) stars dynamically linked to NGC 1851 are present at least up to ~2.5 tidal radii, supporting the presence of a halo of stars surrounding the cluster; (ii) apart from the NGC 1851 radial velocity-like stars, our observed velocity distribution agrees with that expected from Galactic models, suggesting that no other substructure (such as a stream) at different radial velocities is present in our field; (iii) the chemical abundances for the s-process elements Sr and Ba are consistent with the s-normal stars observed in NGC 1851; (iv) all halo stars have metallicities, and abundances for the other studied elements Ca, Mg and Cr, consistent with those exhibited by the cluster. The complexity of the whole NGC 1851 cluster+halo system may agree with the scenario of a tidally disrupted dwarf galaxy in which NGC 1851 was originally embedded.
5000. Photometry and Coravel observations of IC 2488
ID:
ivo://CDS.VizieR/J/A+A/399/543
Title:
Photometry and Coravel observations of IC 2488
Short Name:
J/A+A/399/543
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new UBV photoelectric observations of 119 stars in the field of the southern open cluster IC 2488, supplemented by DDO and Washington photometry and Coravel radial velocities for a sample of red giant candidates. Nearly 50% of the stars sampled - including three red giants and one blue straggler - are found to be probable cluster members. Photometric membership probabilities of the red giant candidates show good agreement with those obtained from Coravel data. A mean radial velocity of -2.63+/-0.06km/s is derived for the cluster giants. The reddening across the cluster is found to be uniform, the mean value being E(B-V)=0.24+/-0.04. IC 2488, located at a distance of (1250+/-120) pc from the Sun and 96 pc below the Galactic plane, is most probably not related to the planetary nebula ESO 166-PN21. A metal abundance [Fe/H]=0.10+/-0.06 relative to the Sun is determined from DDO data of the red giant members, in good agreement with the [Fe/H] values derived from five independent Washington abundance indices. An age of 180Myr is determined from the fitting of isochrones computed with convective overshooting for Z=0.019. The isochrone for logt=8.25 reproduces remarkably well not only the morphology of the upper main sequence but also the observed red giant pattern.