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1751. Identify giant radio sources from the NVSS
ID:
ivo://CDS.VizieR/J/ApJS/224/18
Title:
Identify giant radio sources from the NVSS
Short Name:
J/ApJS/224/18
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results of the application of pattern-recognition techniques to the problem of identifying giant radio sources (GRSs) from the data in the NVSS catalog are presented, and issues affecting the process are explored. Decision-tree pattern-recognition software was applied to training-set source pairs developed from known NVSS large-angular-size radio galaxies. The full training set consisted of 51195 source pairs, 48 of which were known GRSs for which each lobe was primarily represented by a single catalog component. The source pairs had a maximum separation of 20' and a minimum component area of 1.87arcmin^2^ at the 1.4mJy level. The importance of comparing the resulting probability distributions of the training and application sets for cases of unknown class ratio is demonstrated. The probability of correctly ranking a randomly selected (GRS, non-GRS) pair from the best of the tested classifiers was determined to be 97.8+/-1.5%. The best classifiers were applied to the over 870000 candidate pairs from the entire catalog. Images of higher-ranked sources were visually screened, and a table of over 1600 candidates, including morphological annotation, is presented. These systems include doubles and triples, wide-angle tail and narrow-angle tail, S- or Z-shaped systems, and core-jets and resolved cores. While some resolved-lobe systems are recovered with this technique, generally it is expected that such systems would require a different approach.
1752. IDEOS redshift catalogue
ID:
ivo://CDS.VizieR/J/MNRAS/455/1796
Title:
IDEOS redshift catalogue
Short Name:
J/MNRAS/455/1796
Date:
21 Oct 2021
Publisher:
CDS
Description:
This is the first of a series of papers on the Infrared Database of Extragalactic Observables from Spitzer (IDEOS). In this work, we describe the identification of optical counterparts of the infrared sources detected in Spitzer Infrared Spectrograph (IRS) observations and the acquisition and validation of redshifts. The IDEOS sample includes all the spectra from the Cornell Atlas of Spitzer/IRS Sources (CASSIS, Lebouteiller et al., 2011ApJS..196....8L, 2015ApJS..218...21L) of galaxies beyond the Local Group. Optical counterparts were identified from correlation of the extraction coordinates with the NASA Extragalactic Database (NED). To confirm the optical association and validate NED redshifts, we measure redshifts with unprecedented accuracy on the IRS spectra ({sigma}({Delta}z/(1+z))~0.0011) by using an improved version of the maximum combined pseudo-likelihood method (MCPL). We perform a multistage verification of redshifts that considers alternate NED redshifts, the MCPL redshift, and visual inspection of the IRS spectrum. The statistics is as follows: the IDEOS sample contains 3361 galaxies at redshift 0<z<6.42 (mean: 0.48, median: 0.14). We confirm the default NED redshift for 2429 sources and identify 124 with incorrect NED redshifts. We obtain IRS-based redshifts for 568 IDEOS sources without optical spectroscopic redshifts, including 228 with no previous redshift measurements. We provide the entire IDEOS redshift catalogue in machine-readable formats. The catalogue condenses our compilation and verification effort, and includes our final evaluation on the most likely redshift for each source, its origin, and reliability estimates.
1753. IFU observations of NGC 4191
ID:
ivo://CDS.VizieR/J/A+A/581/A65
Title:
IFU observations of NGC 4191
Short Name:
J/A+A/581/A65
Date:
21 Oct 2021
Publisher:
CDS
Description:
We here distinguish two counter-rotating stellar components in NGC 4191 and characterize their physical properties such as kinematics, size, morphology, age, metallicity. We obtained integral field spectroscopic observations with VIRUS-W and used a spectroscopic decomposition technique to separate the contribution of two stellar components to the observed galaxy spectrum. We also performed a photometric decomposition, modeling the galaxy with a Sersic bulge and two exponential disks of different scale length, with the aim of associating these structural components with the kinematic components. We then measured the equivalent width of the absorption line indices on the best-fit models that represent the kinematic components and compared our measurements to the predictions of stellar population models that also account for the variable abundance ratio of {alpha} elements.
1754. i*g* photometry of SDSS EDR galaxies
ID:
ivo://CDS.VizieR/J/ApJ/588/218
Title:
i*g* photometry of SDSS EDR galaxies
Short Name:
J/ApJ/588/218
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we present a new statistic for quantifying galaxy morphology based on measurements of the Gini coefficient of galaxy light distributions. This statistic is easy to measure and is commonly used in econometrics to measure how wealth is distributed in human populations. When applied to galaxy images, the Gini coefficient provides a quantitative measure of the inequality with which a galaxy's light is distributed among its constituent pixels. We measure the Gini coefficient of local galaxies in the Early Data Release of the Sloan Digital Sky Survey and demonstrate that this quantity is closely correlated with measurements of central concentration, but with significant scatter.
1755. IJKs photometry of late-type stars in Draco dSph
ID:
ivo://CDS.VizieR/J/A+A/442/165
Title:
IJKs photometry of late-type stars in Draco dSph
Short Name:
J/A+A/442/165
Date:
21 Oct 2021
Publisher:
CDS
Description:
With the William Herschel Telescope in La Palma we made IJKs observations of an area of about 40'x30' of the Local Group galaxy Draco. This allows us to describe Draco's late-type stellar population across the whole galaxy at a photometric level 2mag deeper than the 2MASS survey. We detected the red giant branch (RGB) and measured the magnitude of the tip of the RGB in the three bands. From that in the I band we obtain a distance modulus of (m-M)_0=19.49+/-0.06(stat)+/-0.15(sys), in excellent agreement with a measurement from RR Lyrae stars. The peak of the (J-Ks)_0_ histogram at different M_Ks_ suggests that Draco has a mean [Fe/H]=-1.95+/-1.26 while fiducial RGB tracks of Galactic globular clusters indicate a mean [Fe/H]=-1.33+/-0.72 where the error corresponds to the spread around the mean value. There are significant differences between the colour-magnitude diagrams of stars in the inner, medium and outer areas of the galaxy. A metal poor (Z=0.0004) intermediate-age population (about 1.6Gyr old) is clearly present and emerges in particular between 6' and 12' from the centre of the galaxy. A few additional carbon star candidates have been identified from both their location in the colour-magnitude diagram and from an indication of variability. The large scale distribution of late-type stars is smooth but irregular in shape; this points at a variation of inclination with radius.
1756. IJKs photometry of late-type stars in NGC 6822
ID:
ivo://CDS.VizieR/J/A+A/429/837
Title:
IJKs photometry of late-type stars in NGC 6822
Short Name:
J/A+A/429/837
Date:
21 Oct 2021
Publisher:
CDS
Description:
Observations in the IJKs wave bands covering the central 20'x20' of the Local Group galaxy NGC 6822 have been made with the William Herschel Telescope in La Palma. They have allowed us to characterize, for the first time in the near-infrared across the whole galaxy, its late-type stellar population (i.e. red giant and asymptotic giant branch stars) and to derive from the ratio between carbon-rich and oxygen-rich asymptotic giant branch stars an indication about spatial variations in metallicity. These amount to about 1.56dex, twice of what has been previously found within each Magellanic Cloud using the same technique. We have calibrated our photometry on the DENIS (I-band) and 2MASS (J and Ks bands) data and obtained a distance modulus of (m-M)_0_=23.34(0.12) from the position of the tip of the RGB. The large scale distribution of late-type stars suggests that either the galaxy is viewed under a high inclination angle or it has a non-negligible thickness.
1757. IK photometry of faint Extremely Red Objects
ID:
ivo://CDS.VizieR/J/MNRAS/346/1125
Title:
IK photometry of faint Extremely Red Objects
Short Name:
J/MNRAS/346/1125
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results from a survey for extremely red objects (EROs) in deep, high-resolution optical images taken from the Hubble Space Telescope (HST) Medium Deep Survey. We have surveyed 35 deep F814W HST/WFPC2 fields in the near-infrared to a typical depth of K>20. From a total area of 206 arcmin^2^ and to a limit of K=20.0, we identify 224 EROs [(1.14+/-0.08)arcmin^-2^] with (I_814_-K)>=4.0 and 83 [(0.41+/-0.05)arcmin^-2^] with (I_814_-K)>=5.0.
1758. Image of Galaxies data-base II.
ID:
ivo://CDS.VizieR/J/A+AS/117/467
Title:
Image of Galaxies data-base II.
Short Name:
J/A+AS/117/467
Date:
21 Oct 2021
Publisher:
CDS
Description:
A preliminary list of 68.040 galaxies was built from extraction of 35.841 digitized images of the Palomar Sky Survey (Paper I, 1996A&A...311...12P). For each galaxy, the basic parameters are obtained: coordinates, diameter, axis ratio, total magnitude, position angle. On this preliminary list, we apply severe selection rules to get a catalog of 28.000 galaxies, well identified and well documented. For each parameter, a comparison is made with standard measurements. The accuracy of the raw photometric parameters is quite good despite of the simplicity of the method. Without any local correction, the standard error on the total magnitude is about 0.5 magnitude up to a total magnitude of B_T_=17. Significant secondary effects are detected concerning the magnitudes: distance to plate center effect and air-mass effect. The description of the construction of the catalog is given in Paturel et al. 1996 and Garnier et al. 1996. Galaxies are detected on POS-I and cross-identified with galaxies from the LEDA database (http://www-obs.univ-lyon1.fr/leda/)
1759. Imaging and spectroscopy around PKS 0405-123
ID:
ivo://CDS.VizieR/J/ApJ/643/680
Title:
Imaging and spectroscopy around PKS 0405-123
Short Name:
J/ApJ/643/680
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a galaxy survey of the field surrounding PKS 0405-123 performed with the WFCCD spectrometer at Las Campanas Observatory. The survey is comprised of two data sets: (1) a greater than 95% complete survey to R=20mag of the field centered on PKS 0405-123 with 10' radius (L~0.1L* and radius of 1Mpc at z=0.1); and (2) a set of four discontiguous (i.e., non-overlapping), flanking fields covering ~1deg^2^ area with completeness ~90% to R=19.5mag. With these data sets, one can examine the local and large-scale galactic environment of the absorption systems identified toward PKS 0405-123. In this paper, we focus on the O VI systems analyzed in Paper I (Prochaska et al., 2004, Cat. <J/ApJ/617/718>). The results suggest that this gas arises in a diverse set of galactic environments including the halos of individual galaxies, galaxy groups, filamentary-like structures, and also regions devoid of luminous galaxies. In this small sample, there are no obvious trends between galactic environment and the physical properties of the gas. Furthermore, we find similar results for a set of absorption systems with comparable NHI but no detectable metal lines. The observations indicate that metals are distributed throughout a wide range of environments in the local universe. Future papers in this series will address the distribution of galactic environments associated with metal-line systems and the Ly forest based on data for over 10 additional fields. All of the spectra and fits tables are available at http://www.ucolick.org/~xavier/WFCCDOVI/
1760. Imaging and spectroscopy in Lynx W
ID:
ivo://CDS.VizieR/J/AJ/148/117
Title:
Imaging and spectroscopy in Lynx W
Short Name:
J/AJ/148/117
Date:
21 Oct 2021
Publisher:
CDS
Description:
RX J0848.6+4453 (Lynx W) at redshift 1.27 is part of the Lynx Supercluster of galaxies. We present an analysis of the stellar populations and star formation history for a sample of 24 members of the cluster. Our study is based on deep optical spectroscopy obtained with Gemini North combined with imaging data from Hubble Space Telescope. Focusing on the 13 bulge-dominated galaxies for which we can determine central velocity dispersions, we find that these show a smaller evolution with redshift of sizes and velocity dispersions than reported for field galaxies and galaxies in poorer clusters. Our data show that the galaxies in RX J0848.6+4453 populate the fundamental plane (FP) similar to that found for lower-redshift clusters. The zero-point offset for the FP is smaller than expected if the cluster's galaxies are to evolve passively through the location of the FP we established in our previous work for z=0.8-0.9 cluster galaxies and then to the present-day FP. The FP zero point for RXJ0848.6+4453 corresponds to an epoch of last star formation at z_form_=1.95_-0.15_^+0.22^. Further, we find that the spectra of the galaxies in RXJ0848.6+4453 are dominated by young stellar populations at all galaxy masses and in many cases show emission indicating low-level ongoing star formation. The average age of the young stellar populations as estimated from the strength of the high-order Balmer line H{zeta} is consistent with a major star formation episode 1-2Gyr prior, which in turn agrees with z_form_=1.95. These galaxies dominated by young stellar populations are distributed throughout the cluster. We speculate that low-level star formation has not yet been fully quenched in the center of this cluster, possibly because the cluster is significantly poorer than other clusters previously studied at similar redshifts, which appear to have very little ongoing star formation in their centers. The mixture in RXJ0848.6+4453 of passive galaxies with young stellar populations and massive galaxies still experiencing some star formation appears similar to the galaxy populations recently identified in two z{approx}2 clusters.

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