- ID:
- ivo://CDS.VizieR/J/MNRAS/455/3413
- Title:
- New white dwarf and subdwarf stars in SDSS DR12
- Short Name:
- J/MNRAS/455/3413
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 6576 new spectroscopically confirmed white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12. We obtain Teff, logg and mass for hydrogen atmosphere white dwarf stars (DAs) and helium atmosphere white dwarf stars (DBs), estimate the calcium/helium abundances for the white dwarf stars with metallic lines (DZs) and carbon/helium for carbon-dominated spectra (DQs). We found one central star of a planetary nebula, one ultracompact helium binary (AM CVn), one oxygen line-dominated white dwarf, 15 hot DO/PG1159s, 12 new cataclysmic variables, 36 magnetic white dwarf stars, 54 DQs, 115 helium-dominated white dwarfs, 148 white dwarf + main-sequence star binaries, 236 metal-polluted white dwarfs, 300 continuum spectra DCs, 230 hot subdwarfs, 2936 new hydrogen-dominated white dwarf stars, and 2675 cool hydrogen-dominated subdwarf stars. We calculate the mass distribution of all 5883 DAs with S/N>=15 in DR12, including the ones in DR7 and DR10, with an average S/N=26, corrected to the 3D convection scale, and also the distribution after correcting for the observed volume, using 1/Vmax.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/4078
- Title:
- New white dwarf stars in SDSS DR10
- Short Name:
- J/MNRAS/446/4078
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 9088 new spectroscopically confirmed white dwarfs and subdwarfs in the Sloan Digital Sky Survey Data Release 10. We obtain T_eff_, logg and mass for hydrogen atmosphere white dwarf stars (DAs) and helium atmosphere white dwarf stars (DBs), and estimate the calcium/helium abundances for the white dwarf stars with metallic lines (DZs) and carbon/helium for carbon-dominated spectra DQs. We found 1 central star of a planetary nebula, 2 new oxygen spectra on helium atmosphere white dwarfs, 71 DQs, 42 hot DO/PG1159s, 171 white dwarf+main-sequence star binaries, 206 magnetic DAHs, 327 continuum-dominated DCs, 397 metal-polluted white dwarfs, 450 helium-dominated white dwarfs, 647 subdwarfs and 6887 new hydrogen-dominated white dwarf stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/196/4
- Title:
- New young star candidates in Taurus-Auriga
- Short Name:
- J/ApJS/196/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Taurus Molecular Cloud subtends a large solid angle on the sky, in excess of 250deg^2^. The search for legitimate Taurus members to date has been limited by sky coverage as well as the challenge of distinguishing members from field interlopers. The Wide-field Infrared Survey Explorer has recently observed the entire sky, and we take advantage of the opportunity to search for young stellar object (YSO) candidate Taurus members from a ~260deg^2^ region designed to encompass previously identified Taurus members. We use near- and mid-infrared colors to select objects with apparent infrared excesses and incorporate other catalogs of ancillary data to present a list of rediscovered Taurus YSOs with infrared excesses (taken to be due to circumstellar disks), a list of rejected YSO candidates (largely galaxies), and a list of 94 surviving candidate new YSO-like Taurus members. There is likely to be contamination lingering in this candidate list, and follow-up spectra are warranted.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1093
- Title:
- NGC7332/7339 and NGC 1156 HI sources from AGES
- Short Name:
- J/AJ/140/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two 5deg^2^ regions around the NGC 7332/9 galaxy pair and the isolated galaxy NGC 1156 have been mapped in the 21cm line of neutral hydrogen (HI) with the Arecibo L-band Feed Array out to a redshift of ~0.065 (~20000km/s) as part of the Arecibo Galaxy Environment Survey. One of the aims of this survey is to investigate the environment of galaxies by identifying dwarf companions and interaction remnants; both of these areas provide the potential for such discoveries. The neutral hydrogen observations were complemented by optical and radio follow-up observations with a number of telescopes. A total of 87 galaxies were found, of which 39 (45%) were previously catalogued and 15 (17%) have prior redshifts. Two dwarf galaxies have been discovered in the NGC 7332 group and a single dwarf galaxy in the vicinity of NGC 1156. A parallel optical search of the area revealed one further possible dwarf galaxy near NGC 7332.
- ID:
- ivo://CDS.VizieR/J/A+A/614/A147
- Title:
- NGC 2070 point sources radial velocities
- Short Name:
- J/A+A/614/A147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce VLT-MUSE observations of the central 2'x2' (30x30pc) of the Tarantula Nebula in the Large Magellanic Cloud. The observations provide an unprecedented spectroscopic census of the massive stars and ionised gas in the vicinity of R136, the young, dense star cluster located in NGC 2070, at the heart of the richest star-forming region in the Local Group. Spectrophotometry and radial-velocity estimates of the nebular gas (superimposed on the stellar spectra) are provided for 2255 point sources extracted from the MUSE datacubes, and we present estimates of stellar radial velocities for 270 early-type stars (finding an average systemic velocity of 271+/-41km/s). We present an extinction map constructed from the nebular Balmer lines, with electron densities and temperatures estimated from intensity ratios of the [SII], [NII], and [SIII] lines. The interstellar medium, as traced by H{alpha} and [NII] {lambda}6583, provides new insights in regions where stars are probably forming. The gas kinematics are complex, but with a clear bi-modal, blue- and red-shifted distribution compared to the systemic velocity of the gas centred on R136. Interesting point-like sources are also seen in the eastern cavity, western shell, and around R136; these might be related to phenomena such as runaway stars, jets, formation of new stars, or the interaction of the gas with the population of Wolf-Rayet stars. Closer inspection of the core reveals red-shifted material surrounding the strongest X-ray sources, although we are unable to investigate the kinematics in detail as the stars are spatially unresolved in the MUSE data. Further papers in this series will discuss the detailed stellar content of NGC 2070 and its integrated stellar and nebular properties.
- ID:
- ivo://CDS.VizieR/J/ApJ/859/52
- Title:
- NGFS. III. Dwarf galaxies in outer regions
- Short Name:
- J/ApJ/859/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 271 previously undetected dwarf galaxies in the outer Fornax cluster regions at radii r_vir_/4<r<r_vir_/2 using data from the Next Generation Fornax Survey (NGFS) with deep coadded u', g', and i' images obtained with Blanco/DECam at Cerro Tololo Interamerican Observatory. From the 271 dwarf candidates, we find 39 to be nucleated. Together with our previous study of the central Fornax region, the new dwarfs detected with NGFS data number 392, of which 56 are nucleated. The total Fornax dwarf galaxy population from NGFS and other catalogs rises, therefore, to a total of 643 with 181 being nucleated, yielding an overall nucleation fraction of 28%. The absolute i'-band magnitudes for the outer NGFS dwarfs are in the range -18.80<=M_i'_<=-8.78 with effective radii r_eff,i'_=0.18-2.22kpc and an average Sersic index <n>_i'_=0.81. Nonnucleated dwarfs are found to be fainter and smaller by {Delta}<M_i'_>=2.25mag and {Delta}<r_eff,i'_>=0.4kpc than the nucleated dwarfs. We demonstrate a significant clustering of dwarf galaxies on scales <~100kpc, and projected surface number density profile estimates, {Sigma}_N_(r), show a concentration of dwarfs in the Fornax core region within r<~350kpc. {Sigma}_N_(r) has a flat distribution up to ~350kpc, beyond which it declines for the nonnucleated dwarfs. The nucleated dwarfs have a steeper {Sigma}N(r) distribution, are more concentrated toward NGC 1399, and are decreasing rapidly outwards. This is the first time the transition from cluster to field environment has been established for the very faint dwarf galaxy population with robust sample statistics.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/30
- Title:
- NIR counterparts to Chandra X-ray sources. I.
- Short Name:
- J/ApJ/703/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 5184 candidate infrared counterparts to X-ray sources detected toward the Galactic center. The X-ray sample contains 9017 point sources detected in this region by the Chandra X-ray Observatory during the past decade, including data from a recent deep survey of the central 2{deg}x0.8{deg} of the Galactic plane. A total of 6760 of these sources have hard X-ray colors, and the majority of them lie near the Galactic center, while most of the remaining 2257 soft X-ray sources lie in the foreground. We cross-correlated the X-ray source positions with the 2MASS and SIRIUS near-infrared catalogs, which collectively contain stars with a 10{sigma} limiting flux of Ks<=15.6mag. For each of the infrared matches to X-ray sources in our catalog we derived the probability that the association is real, based on the source properties and the results of the cross-correlation analysis.
- ID:
- ivo://CDS.VizieR/J/ApJ/761/22
- Title:
- NIR galaxy cluster candidates in the SPT survey
- Short Name:
- J/ApJ/761/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the ground- and space-based optical and near-infrared (NIR) follow-up of 224 galaxy cluster candidates detected with the Sunyaev-Zel'dovich (SZ) effect in the 720deg^2^ of the South Pole Telescope (SPT) survey completed in the 2008 and 2009 observing seasons. We use the optical/NIR data to establish whether each candidate is associated with an overdensity of galaxies and to estimate the cluster redshift. Most photometric redshifts are derived through a combination of three different cluster redshift estimators using red-sequence galaxies, resulting in an accuracy of {Delta}z/(1+z)=0.017, determined through comparison with a subsample of 57 clusters for which we have spectroscopic redshifts. We successfully measure redshifts for 158 systems and present redshift lower limits for the remaining candidates. The redshift distribution of the confirmed clusters extends to z=1.35 with a median of z_med_=0.57. Approximately 18% of the sample with measured redshifts lies at z>0.8. We estimate a lower limit to the purity of this SPT SZ-selected sample by assuming that all unconfirmed clusters are noise fluctuations in the SPT data. We show that the cumulative purity at detection significance {xi}>5 ({xi}>4.5) is >=95% (>=70%). We present the red brightest cluster galaxy (rBCG) positions for the sample and examine the offsets between the SPT candidate position and the rBCG. The radial distribution of offsets is similar to that seen in X-ray-selected cluster samples, providing no evidence that SZ-selected cluster samples include a different fraction of recent mergers from X-ray-selected cluster samples.
- ID:
- ivo://CDS.VizieR/J/AJ/141/105
- Title:
- NIR-matched quasar catalog
- Short Name:
- J/AJ/141/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of over 130000 quasar candidates with near-infrared (NIR) photometric properties, with an areal coverage of approximately 1200deg^2^. This is achieved by matching the Sloan Digital Sky Survey (SDSS) in the optical ugriz bands to the UKIRT Infrared Digital Sky Survey (UKIDSS) Large Area Survey (LAS) in the NIR YJHK bands. We match the ~1 million SDSS DR6 Photometric Quasar catalog to Data Release 3 of the UKIDSS LAS (ULAS) and produce a catalog with 130827 objects with detections in one or more NIR bands, of which 74351 objects have optical and K-band detections and 42133 objects have the full nine-band photometry.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/52
- Title:
- NIR survey of Spitzer YSOs in Orion Mol. Cloud
- Short Name:
- J/ApJ/821/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a near-infrared survey for the visual multiples in the Orion molecular clouds region at separations between 100 and 1000au. These data were acquired at 1.6um with the NICMOS and WFC3 cameras on the Hubble Space Telescope. Additional photometry was obtained for some of the sources at 2.05um with NICMOS and in the L' band with NSFCAM2 on NASA's InfraRed Telescope Facility. Toward 129 protostars and 197 pre-main-sequence stars with disks observed with WFC3, we detect 21 and 28 candidate companions between the projected separations of 100-1000au, of which less than 5 and 8, respectively, are chance line-of-sight coincidences. The resulting companion fraction (CF) after the correction for the line-of-sight contamination is 14.4_-1.3_^+1.1^ for protostars and 12.5_-0.8_^+1.2^ for the pre-main-sequence stars. These values are similar to those found for main-sequence stars, suggesting that there is little variation in the CF with evolution, although several observational biases may mask a decrease in the CF from protostars to the main-sequence stars. After segregating the sample into two populations based on the surrounding surface density of young stellar objects, we find that the CF in the high stellar density regions ({Sigma}_YSO_>45pc^-2^) is approximately 50% higher than that found in the low stellar density regions ({Sigma}_YSO_<45pc^-2^). We interpret this as evidence for the elevated formation of companions at 100-1000 au in the denser environments of Orion. We discuss possible reasons for this elevated formation.
