- ID:
- ivo://CDS.VizieR/J/ApJS/243/14
- Title:
- The Ogle et al. Galaxy Catalog (OGC)
- Short Name:
- J/ApJS/243/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of the 1525 most optically luminous galaxies from the Sloan Digital Sky Survey with r-band luminosity L_r_>8L* and redshift z<0.3, including 84 super spirals, 15 super lenticulars, 14 super post-merger galaxies, and 1400 giant ellipticals. With mass in stars of 10^11.3^-10^12^M_{sun}_, super spirals and lenticulars are the most massive disk galaxies currently known. The specific star formation rates of super spirals place them on or below the star-forming main sequence. They must have formed stars at a high rate throughout their history in order to grow their massive, gigantic stellar disks and maintain their blue u-r integrated colors. Their disks are red on the inside and blue on the outside, consistent with inside-out growth. They tend to have small bulge-to-total (B/T) r-band luminosity ratios, characteristic of disk building via minor mergers and cold accretion. A large percentage of super disk galaxies (41%) have double nuclei, double disks, or other signatures of ongoing mergers. Most (72%) are found in moderate- to low-density environments, while the rest are found at the outskirts of clusters. It is likely that super spirals survive in these environments because they continue to accrete cold gas and experience only minor mergers at late times, by virtue of their enormous masses and angular momenta. We suggest that super post-mergers are the product of super spiral major mergers and may be the precursors of some giant elliptical galaxies found in low-density environments.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/896/77
- Title:
- The PHLEK survey: oxygen & helium abundances
- Short Name:
- J/ApJ/896/77
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We present Keck NIRSPEC and Keck NIRES spectroscopy of sixteen metal-poor galaxies that have pre-existing optical observations. The near-infrared (NIR) spectroscopy specifically targets the HeI{lambda}10830{AA} emission line, due to its sensitivity to the physical conditions of the gas in HII regions. We use these NIR observations, combined with optical spectroscopy, to determine the helium abundance of sixteen galaxies across a metallicity range 12+log_10_(O/H)=7.13-8.00. This data set is combined with two other samples where metallicity and helium abundance measurements can be secured: star-forming galaxies selected from the Sloan Digital Sky Survey spectroscopic database, and existing low-metallicity systems in the literature. We calculate a linear fit to these measurements, accounting for intrinsic scatter, and report a new determination of the primordial helium number abundance, y_P_=0.0805_-0.0017_^+0.0017^, which corresponds to a primordial helium mass fraction Y_P_=0.2436_-0.0040_^+0.0039^. Using our determination of the primordial helium abundance in combination with the latest primordial deuterium measurement, (D/H)_P_x10^5^=2.527+/-0.030, we place a bound on the baryon density {Omega}_b_h^2^=0.0215_-0.0005_^+0.0005^ and the effective number of neutrino species N_eff_=2.85_-0.25_^+0.28^. These values are in 1.3{sigma} agreement with those deduced from the Planck satellite observations of the temperature fluctuations imprinted on the cosmic microwave background.
- ID:
- ivo://CDS.VizieR/J/AJ/157/35
- Title:
- The population of pulsating variable stars in Sextans
- Short Name:
- J/AJ/157/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large extension of the Sextans dwarf spheroidal galaxy, 7 deg^2^, has been surveyed for variable stars using the Dark Energy Camera at the Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile. We report seven anomalous Cepheids, 199 RR Lyrae stars, and 16 dwarf Cepheids in the field. This is only the fifth extragalactic system in which dwarf Cepheids have been systematically searched. Henceforth, the new stars increase the census of stars coming from different environments that can be used to asses the advantages and limitations of using dwarf Cepheids as standard candles in populations for which the metallicity is not necessarily known. The dwarf Cepheids found in Sextans have a mean period of 0.066 day and a mean g amplitude of 0.87 mag. They are located below the horizontal branch, spanning a range of 0.8 mag: 21.9<g<22.7. The number of dwarf Cepheids in Sextans is low compared with other galaxies such as Carina, which has a strong intermediate-age population. On the other hand, the number and ratio of RR Lyrae stars to dwarf Cepheids are quite similar to those of Sculptor, a galaxy which, as Sextans, is dominated by an old stellar population. The dwarf Cepheid stars found in Sextans follow a well-constrained period-luminosity relationship with an rms=0.05 mag in the g band, which was set up by anchoring to the distance modulus given by the RR Lyrae stars. Although the majority of the variable stars in Sextans are located toward the center of the galaxy, we have found two RR Lyrae stars and one anomalous Cepheid in the outskirts of the galaxy that may be extratidal stars and suggest that this galaxy may be undergoing tidal destruction. These possible extratidal variable stars share the same proper motions as Sextans, as seen by recent Gaia measurements. Two additional stars that we initially classified as foreground RR Lyrae stars may actually be other examples of Sextans extratidal anomalous Cepheids, although radial velocities are needed to prove that scenario.
- ID:
- ivo://CDS.VizieR/J/MNRAS/491/5317
- Title:
- The SDSS extended PSFs
- Short Name:
- J/MNRAS/491/5317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A robust and extended characterization of the Point Spread Function (PSF) is crucial to extract the photometric information produced by deep imaging surveys. Here we present the extended PSFs of the Sloan Digital Sky Survey (SDSS), one of the most productive astronomical surveys of all time. By stacking ~1000 images of individual stars with different brightness, we obtain the bidimensional SDSS PSFs extending over 8 arcmin in radius for all the SDSS filters (u, g, r, i, z). This new characterization of the SDSS PSFs is near a factor of 10 larger in extension than previous PSFs characterizations of the same survey. We found asymmetries in the shape of the PSFs caused by the drift scanning observing mode. The flux of the PSFs is larger along the drift scanning direction. Following a reproducible science philosophy, we make all the PSF models and the used tools publicly available. Finally, we illustrate with an example how the PSF models can be used to remove the scattered light field produced by the brightest stars in the Coma Cluster central region. This particular example shows the huge importance of PSFs in the study of the low surface brightness Universe, especially with the upcoming of ultra-deep surveys such as the Large Synoptic Survey Telescope (LSST).
- ID:
- ivo://CDS.VizieR/J/ApJ/705/1099
- Title:
- The Sloan Lens ACS (SLACS) Survey. IX.
- Short Name:
- J/ApJ/705/1099
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the current photometric data set for the Sloan Lens ACS (SLACS) Survey, including Hubble Space Telescope (HST) photometry from Advanced Camera for Surveys, WFPC2, and NICMOS. These data have enabled the confirmation of an additional 15 grade "A" (certain) lens systems, bringing the number of SLACS grade "A" lenses to 85; including 13 grade "B" (likely) systems, SLACS has identified nearly 100 lenses and lens candidates. Approximately 80% of the grade "A" systems have elliptical morphologies while ~10% show spiral structure; the remaining lenses have lenticular morphologies. Spectroscopic redshifts for the lens and source are available for every system, making SLACS the largest homogeneous data set of galaxy-scale lenses to date. The ensemble properties of the SLACS lens galaxies, e.g., stellar masses and projected ellipticities, appear to be indistinguishable from other SDSS galaxies with similar stellar velocity dispersions. This further supports that SLACS lenses are representative of the overall population of massive early-type galaxies with M_*_>~10^11^M_{sun}_, and are therefore an ideal data set to investigate the kpc-scale distribution of luminous and dark matter in galaxies out to z~0.5.
- ID:
- ivo://CDS.VizieR/J/ApJ/690/670
- Title:
- The Sloan lens ACS Survey. VIII.
- Short Name:
- J/ApJ/690/670
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens - the projected number density of galaxies inside the tenth nearest neighbor ({Sigma}_10_) and within a cone of radius 1h^-1^Mpc (D1).
- ID:
- ivo://CDS.VizieR/J/ApJ/741/79
- Title:
- The Spitzer-SDSS-GALEX Spectroscopic Survey
- Short Name:
- J/ApJ/741/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Spitzer-SDSS-GALEX Spectroscopic Survey (SSGSS) provides a new sample of 101 star-forming galaxies at z<0.2 with unprecedented multi-wavelength coverage. New mid- to far-infrared spectroscopy from the Spitzer Space Telescope is added to a rich suite of previous imaging and spectroscopy, including ROSAT, Galaxy Evolution Explorer, Sloan Digital Sky Survey, Two Micron All Sky Survey, and Spitzer/SWIRE. Sample selection ensures an even coverage of the full range of normal galaxy properties, spanning two orders of magnitude in stellar mass, color, and dust attenuation. In this paper we present the SSGSS data set, describe the science drivers, and detail the sample selection, observations, data reduction, and quality assessment.
898. The SSRS2 Sample
- ID:
- ivo://CDS.VizieR/J/AJ/108/1987
- Title:
- The SSRS2 Sample
- Short Name:
- J/AJ/108/1987
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we continue our investigation on the isophotal nature, accuracy, and uniformity of the magnitude system adopted in the Southern Sky Redshift Survey extension (SSRS2). Extending our earlier work, we examine galaxies in the equatorial region, primarily in the declination range -17.5 deg <= Dec. <= 0 deg, over a large range of right ascension, covering the southern and northern Galactic caps. For this purpose, we have obtained CCD isophotal magnitudes in the B and R bands for 265 galaxies of different morphological types. Using this larger sample we confirm our earlier claim that the m(SSRS2) magnitudes are very nearly the magnitude measured within the isophote mu_B = 26 mag/arcsec^2, with a dispersion of about 0.30 mag. The relative zero-point offset between our m(SSRS2) magnitudes and CCD photometry is -0.02 mag from all data we have obtained. However, we detect a variation of the zero-point across different regions of the sky of +/- 0.10 mag for regions at large angular separations. We also estimate that the zero-point offset between the m(SSRS2) and Zwicky systems is relatively small (~0.10 mag), which should allow us to combine the data from the SSRS2 and the CfA2 Redshift Survey.
- ID:
- ivo://CDS.VizieR/III/250
- Title:
- The VIMOS VLT deep survey (VVDS-DEEP)
- Short Name:
- III/250
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/ApJ/750/97
- Title:
- The yellow and red supergiants of M33
- Short Name:
- J/ApJ/750/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Yellow and red supergiants are evolved massive stars whose numbers and locations on the Hertzsprung-Russell (H-R) diagram can provide a stringent test for models of massive star evolution. Previous studies have found large discrepancies between the relative number of yellow supergiants (YSGs) observed as a function of mass and those predicted by evolutionary models, while a disagreement between the predicted and observed locations of red supergiants (RSGs) on the H-R diagram was only recently resolved. Here, we extend these studies by examining the YSG and RSG populations of M33. Unfortunately, identifying these stars is difficult as this portion of the color-magnitude diagram is heavily contaminated by foreground dwarfs. We identify the RSGs through a combination of radial velocities and a two-color surface gravity discriminant, and after re-characterizing the rotation curve of M33 with our newly selected RSGs, we identify the YSGs through a combination of radial velocities and the strength of the OI{lambda}7774 triplet. We examine ~1300 spectra in total and identify 121 YSGs (a sample that is unbiased in luminosity above log(L/L_{sun}_)~4.8) and 189 RSGs. After placing these objects on the H-R diagram, we find that the latest generation of Geneva evolutionary tracks shows excellent agreement with the observed locations of our RSGs and YSGs, the observed relative number of YSGs with mass, and the observed RSG upper mass limit.