- ID:
- ivo://CDS.VizieR/J/AJ/131/582
- Title:
- Cool white dwarfs in the SDSS
- Short Name:
- J/AJ/131/582
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A reduced proper motion diagram utilising Sloan Digital Sky Survey (SDSS) photometry and astrometry and USNO-B plate astrometry is used to separate cool white dwarf candidates from metal-weak, high-velocity, main-sequence Population II stars (subdwarfs) in the SDSS Data Release 2 imaging area. Follow-up spectroscopy using the Hobby-Eberly Telescope, the MMT, and the McDonald 2.7m telescope is used to demonstrate that the white dwarf and subdwarf loci separate cleanly in the reduced proper motion diagram and that the contamination by subdwarfs is small near the cool white dwarf locus.
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- ID:
- ivo://CDS.VizieR/J/AJ/154/72
- Title:
- Coordinates and photometry of stars in Haffner 16
- Short Name:
- J/AJ/154/72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Images and spectra recorded with the Gemini Multi-Object Spectrograph on Gemini South are used to investigate the stellar content of the open cluster Haffner 16. The (i',g'-i') color-magnitude diagram (CMD) constructed from these data extends over 10mag in i', sampling the cluster main sequence (MS) and 5mag of the pre-MS (PMS). The fraction of unresolved equal mass binaries among PMS stars is estimated to be 0.6+/-0.1. The isochrones do not track the PMS on the CMD, in the sense that the PMS has a shallower slope on the CMD than predicted by the models. Still, a dip in star counts, which is associated with the relaxation of PMS stars onto the MS, is identified near i'=17. The depth and brightness of this feature-as well as the morphology of the cluster MS on the CMD-are matched by models with a slightly sub-solar metallicity that have an age of ~20Myr and a distance modulus of 12.3+/-0.2. A light profile of Haffner 16 is constructed in the W1 filter ({lambda}_cen_=3.4{mu}m), which suggests that the cluster is surrounded by a diffuse stellar halo. Spectra of candidate cluster MS and PMS stars selected according to location on the CMD are presented. The spectra show characteristics that are suggestive of a sub-solar metallicity. H{alpha} emission is common among objects on the PMS locus on the CMD near i'=18. It is suggested that the location of the Haffner 16 PMS on the CMD is affected by large-scale cool spot activity, likely induced by rapid stellar rotation.
- ID:
- ivo://CDS.VizieR/J/ApJ/896/3
- Title:
- Cosmicflows-4: Tully-Fisher relation calibrations
- Short Name:
- J/ApJ/896/3
- Date:
- 07 Mar 2022 07:21:25
- Publisher:
- CDS
- Description:
- This study is a part of the Cosmicflows-4 project with the aim of measuring the distances of more than ~10000 spiral galaxies in the local universe up to ~15000km/s. New HI line width information has come primarily from the Arecibo Legacy Fast ALFA Survey. Photometry of our sample galaxies has been carried out in optical (SDSS u, g, r, i, and z) and infrared (WISE W1 and W2) bands. Inclinations have been determined using an online graphical interface accessible to a collaboration of citizen scientists. Galaxy distances are measured based on the correlation between the rotation rate of spirals and their absolute luminosity, known as the Tully-Fisher relation (TFR). In this study, we present the calibration of the TFR using a subsample of ~600 spirals located in 20 galaxy clusters. Correlations among such observables as color, surface brightness, and relative HI content are explored in an attempt to reduce the scatter about the TFR with the goal of obtaining more accurate distances. A preliminary determination of the Hubble constant from the distances and velocities of the calibrator clusters is H0=76.0+/-1.1(stat.)+/-2.3(sys.)km/s/Mpc.
- ID:
- ivo://CDS.VizieR/J/ApJS/172/523
- Title:
- COSMOS field Ly{alpha} emitters at z~5.7
- Short Name:
- J/ApJS/172/523
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a narrow-band optical survey of a contiguous area of 1.95deg^2^, covered by the Cosmic Evolution Survey (COSMOS). Both optical narrow-band ({lambda}c=8150{AA} and {delta}{lambda}=120{AA}) and broad-band (B, V, g', r', i', and z') imaging observations were performed with the Subaru prime-focus camera, Suprime-Cam on the Subaru Telescope. We provide the largest contiguous narrow-band survey, targeting Ly{alpha} emitters (LAEs) at z~5.7. We find a total of 119 LAE candidates at z~5.7. Over the wide-area covered by this survey, we find no strong evidence for large-scale clustering of LAEs. We estimate a star formation rate (SFR) density of ~7x10-4M_{sun}_/yr/Mpc^3^ for LAEs at z~5.7 and compare it with previous measurements.
- ID:
- ivo://CDS.VizieR/II/284
- Title:
- COSMOS Multi-Wavelength Photometry Catalog
- Short Name:
- II/284
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present imaging data and photometry for the COSMOS survey in 15 photometric bands between 0.3 and 2.4m. These include data taken on the Subaru 8.3m telescope, the KPNO and CTIO 4m telescopes, and the CFHT 3.6m telescope. Special techniques are used to ensure that the relative photometric calibration is better than 1% across the field of view. The absolute photometric accuracy from standard-star measurements is found to be 6%. The absolute calibration is corrected using galaxy spectra, providing colors accurate to 2% or better. Stellar and galaxy colors and counts agree well with the expected values. Finally, as the first step in the scientific analysis of these data we construct panchromatic number counts which confirm that both the geometry of the universe and the galaxy population are evolving.
- ID:
- ivo://CDS.VizieR/J/A+A/436/91
- Title:
- C star population in outer disk of M31
- Short Name:
- J/A+A/436/91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We employ the CFHT Megacam camera to survey ~1{deg}^2^ of the southern outer disc of M31, a region which includes the area where Battinelli et al. (2003, Cat. <J/AJ/125/1298>) have identified nearly one thousand C stars. In the outer M31 region not previously surveyed, we identify 361 new C star candidates, having similar photometric properties to the known ones, and confirm the slight decrease in the luminosity of C stars with galactocentric distances. We show that the Sloan g', r', i' filters are a viable approach, comparable to (CN-TiO), to identify C stars. We find that the (g'-r') colours of cool C stars can be so red that prohibitively long g' exposures are needed to acquire faint extragalactic C stars. This makes the Sloan filters a less promising approach to extend a C star survey to several Mpc. Our uniform large field survey detects the edge of M31 disk at ~35kpc. The intermediate-age population, represented by C stars, extends further to ~40kpc.
- ID:
- ivo://CDS.VizieR/J/AJ/142/181
- Title:
- CVs from SDSS. VIII. The final year
- Short Name:
- J/AJ/142/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper completes the series of cataclysmic variables (CVs) identified from the Sloan Digital Sky Survey (SDSS) I/II. The coordinates, magnitudes, and spectra of 33 CVs are presented. Among the 33 are eight systems known prior to SDSS (CT Ser, DO Leo, HK Leo, IR Com, V849 Her, V405 Peg, PG1230+226, and HS0943+1404), as well as nine objects recently found through various photometric surveys. Among the systems identified since the SDSS are two polar candidates, two intermediate polar candidates, and one candidate for containing a pulsating white dwarf. Our follow-up data have confirmed a polar candidate from Paper VII and determined tentative periods for three of the newly identified CVs. A complete summary table of the 285 CVs with spectra from SDSS I/II is presented as well as a link to an online table of all known CVs from both photometry and spectroscopy that will continue to be updated as future data appear.
- ID:
- ivo://CDS.VizieR/J/MNRAS/417/1210
- Title:
- DA-white dwarfs from SDSS and UKIDSS
- Short Name:
- J/MNRAS/417/1210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a method which uses colour-colour cuts on the Sloan Digital Sky Survey (SDSS) photometry to select white dwarfs with hydrogen-rich (DA) atmospheres without the recourse to spectroscopy. This method results in a sample of DA white dwarfs that is 95 per cent complete at an efficiency of returning a true DA white dwarf of 62 per cent. The approach was applied to SDSS Data Release 7 for objects with and without SDSS spectroscopy.
- ID:
- ivo://CDS.VizieR/J/ApJ/882/106
- Title:
- DB white dwarfs with SDSS and Gaia data
- Short Name:
- J/ApJ/882/106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive analysis of DB white dwarfs drawn from the Sloan Digital Sky Survey, based on model fits to ugriz photometry and medium-resolution spectroscopy from the Sloan Digital Sky Survey. We also take advantage of the exquisite trigonometric parallax measurements recently obtained by the Gaia mission. Using the so-called photometric and spectroscopic techniques, we measure the atmospheric and physical parameters of each object in our sample (Teff, logg, H/He, Ca/He, R, M), and compare the values obtained from both techniques in order to assess the precision and accuracy of each method. We then explore in great detail the surface gravity, stellar mass, and hydrogen abundance distributions of DB white dwarfs as a function of effective temperature. We present some clear evidence for a large population of unresolved double-degenerate binaries composed of DB+DB and even DB+DA white dwarfs. In the light of our results, we finally discuss the spectral evolution of DB white dwarfs, in particular the evolution of the DB-to-DA ratio as a function of Teff, and we revisit the question of the origin of hydrogen in DBA white dwarfs.
- ID:
- ivo://CDS.VizieR/J/A+A/598/A32
- Title:
- 2D decomposition of CALIFA galaxies
- Short Name:
- J/A+A/598/A32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a two-dimensional multi-component photometric decomposition of 404 galaxies from the Calar Alto Legacy Integral Field Area Data Release 3 (CALIFA-DR3). They represent all possible galaxies with no clear signs of interaction and not strongly inclined in the final CALIFA data release. Galaxies are modelled in the g, r, and i Sloan Digital Sky Survey (SDSS) images including, when appropriate, a nuclear point source, bulge, bar, and an exponential or broken disc component. We use a human-supervised approach to determine the optimal number of structures to be included in the fit. The dataset, including the photometric parameters of the CALIFA sample, is released together with statistical errors and a visual analysis of the quality of each fit. The analysis of the photometric components reveals a clear segregation of the structural composition of galaxies with stellar mass. At high masses (log(M*/M_{sun}_)>11), the galaxy population is dominated by galaxies modelled with a single Sersic or a bulge+disc with a bulge-to-total (B/T) luminosity ratio B/T>0.2. At intermediate masses (9.5<log(M*/M_{sun}_)<11), galaxies described with bulge+disc but B/T<0.2 are preponderant, whereas, at the low mass end (log(M*/M_{\sun}_)<9.5), the prevailing population is constituted by galaxies modelled with either pure discs or nuclear point sources+discs (i.e., no discernible bulge). The analyses of the extended multi-component radial profile result in a volume-corrected distribution of 62%, 28%, and 10% for the so-called Type I (pure exponential), Type II (down-bending), and Type III (up-bending) disc profiles, respectively. These fractions are in discordance with previous findings. We argue that the different methodologies used to detect the breaks are the main cause for these differences.
