- ID:
- ivo://CDS.VizieR/J/other/PPMtO/17B.1
- Title:
- Radio properties of ROSAT sources
- Short Name:
- J/other/PPMtO/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A cross-identification of the southern-sky objects with the ROSAT All-Sky Survey (Cat. <IX/10>) and Parkes-MIT-NRAO (PMN) Radio (5GHz) Survey (Cat. <VIII/38>) yields a list of 642 sources. Subsequential optical identification for all these coincidences has been taken to form a large sample of galaxies and Active Galactic Nuclei (AGNs). As a result, 311 (52%) were previously optically identified as extragalactic objects. The fluxes detected from X-ray, optical, and radio bands for them are compiled. This database allows an investigation on broad band energy distribution and other possible correlations among spectral indices and luminosities for various types of extragalactic objects.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/506/1477
- Title:
- Radio source distribution
- Short Name:
- J/A+A/506/1477
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Information on physical characteristics of astrometric radio sources, such as magnitude and redshift, is of great importance for many astronomical studies. However, data usually used in radio astrometry is often incomplete and outdated. Our purpose is to study the optical characteristics of more than 4000 radio sources observed by the astrometric VLBI technique since 1979. We also studied the effect of the asymmetry in the distribution of the reference radio sources on the correlation matrices between vector spherical harmonics of the first and second degrees. The radio source characteristics were mainly taken from the NASA/IPAC Extragalactic Database (NED). Characteristics of the gravitational lenses were checked with the CfA-Arizona Space Telescope LEns Survey. SIMBAD and HyperLeda databases were also used to clarify the characteristics of some objects. Also we simulated and investigated a list of 4000 radio sources evenly distributed around the celestial sphere. We estimated the correlation matrices between the vector spherical harmonics using the real as well as modelled distribution of the radio sources.
- ID:
- ivo://CDS.VizieR/J/AN/341/703
- Title:
- Radio spectral indices of active galaxies
- Short Name:
- J/AN/341/703
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we investigate radio properties of active galaxies taken from the reference Veron-Cetty & Veron (2010, Cat. VII/258) catalog. The galaxies are limited to magnitudes in the range of 12^m^-19^m^. We have cross-correlated the list with radio catalogs and selected those galaxies that have data on six or more radio fluxes at different wavelengths. As a result, we have 198 galaxies that satisfy these conditions. Using SDSS DR15, we have obtained 96 spectroscopic identifications of the 198 objects. After the classification, 85% of the 96 objects have changed their types. Available data on the classification of these objects and our classification showed that 56.7% of them are Seyfert galaxies. For all the objects, we have built radio spectra and estimated radio spectral indices. As a result, we obtain {alpha}>=-0.6089+/-0.056> ({alpha}_Seyfert_=-0.6013+/-0.027, {alpha}_LINER_=-0.5955+/-0.025, {alpha}_HII_=-0.6672+/-0.039, {alpha}_Comp._=-0.7128+/-0.043). We discuss the radio properties of active galaxies based on their radio spectral indices.
294. RASS AGN sample
- ID:
- ivo://CDS.VizieR/J/A+AS/139/575
- Title:
- RASS AGN sample
- Short Name:
- J/A+AS/139/575
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of a program to identify the unknown bright active galactic nuclei (AGN) in the ROSAT All Sky Survey Bright Source Catalog (RASS-BSC). We have used logC+0.4R as an alternative expression for log(f_X_/f_opt_), where C is X-ray count rate and R stands for R magnitude. Then a high X-ray-to-optical flux ratio criterion has been used to select an AGN sample with 165 unidentified X-ray sources for optical spectroscopy. Those 165 X-ray sources have been identified in the following classes: 115 emission line AGN (QSOs and Seyferts), 2 BL Lac objects and 4 BL Lac candidates, 22 clusters of galaxies, 12 Galactic stars and 10 objects remain unidentified. This represent a success rate of about 73% for detecting AGN using our selection criteria. Plausibility is based upon the optical classification and X-ray characteristics of the sources.
- ID:
- ivo://CDS.VizieR/J/A+A/427/397
- Title:
- Redshifts of 5 EDisCS galaxy clusters
- Short Name:
- J/A+A/427/397
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic observations are presented for objects in the fields of 4 galaxy clusters at z=0.7-0.8 (Cl 1040.7-1155 (Cl 1040), Cl 1054.4-1146 (Cl 1054-11), Cl 1054.7-1245 (Cl 1054-12), and Cl 1216.8-1201 (Cl 1216)) and in one cluster at z~0.5 (Cl 1232.5-1250 (Cl 1232)) of the ESO Distant Cluster Survey (EDisCS). We present tables of RA and DE positions for an equinox of 2000 (J2000, epoch 2001), I-band magnitudes for an aperture of radius 1 arcsecond, spectroscopic redshifts for objects in the fields of our 5 clusters, and membership and targeting flags to indicate whether the object is a cluster member and/or was targeted to be a cluster member respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/116/1573
- Title:
- Redshift Survey Compact Groups
- Short Name:
- J/AJ/116/1573
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Redshift Survey Compact Groups (RSCGs) are tight knots of N>=3 galaxies selected from the CfA2+SSRS2 redshift survey. The selection is based on physical extent and association in redshift space alone. We measured 300 new redshifts of fainter galaxies within 1h^-1^Mpc of 14 RSCGs to explore the relationship between RSCGs and their environments. Thirteen of 14 RSCGs are embedded in overdense regions of redshift space. The systems range from a loose group of five members to an Abell cluster. The remaining group, RSCG 64, appears isolated. RSCGs are isolated and distinct from their surroundings to varying degrees, as are the Hickson compact groups. Among the 13 embedded RSCGs, three are distinct from their general environments (RSCG 9, RSCG 11, and RSCG 85).
- ID:
- ivo://CDS.VizieR/J/ApJ/703/420
- Title:
- Red supergiants in M31
- Short Name:
- J/ApJ/703/420
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Red supergiants (RSGs) are a short-lived stage in the evolution of moderately massive stars (10-25M_{sun}_), and as such their location in the H-R diagram provides an exacting test of stellar evolutionary models. Since massive star evolution is strongly affected by the amount of mass loss a star suffers, and since the mass-loss rates depend upon metallicity, it is highly desirable to study the physical properties of these stars in galaxies of various metallicities. Here we identify a sample of RSGs in M31, the most metal-rich of the Local Group galaxies. We determine the physical properties of these stars using both moderate resolution spectroscopy and broadband V-K photometry. We find that on average the RSGs of our sample are variable in V by 0.5mag, smaller but comparable to the 0.9mag found for Magellanic Cloud (MC) RSGs. No such variability is seen at K, also in accord with what we know of Galactic and MC RSGs.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/196
- Title:
- REQUIEM survey. I. Ly{alpha} halos around QSOs
- Short Name:
- J/ApJ/887/196
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The discovery of quasars a few hundred megayears after the Big Bang represents a major challenge to our understanding of black holes as well as galaxy formation and evolution. Quasars' luminosity is produced by extreme gas accretion onto black holes, which have already reached masses of M_BH_>10^9^M_{sun}_ by z~6. Simultaneously, their host galaxies form hundreds of stars per year, using up gas in the process. To understand which environments are able to sustain the rapid formation of these extreme sources, we started a Very Large Telescope/Multi-Unit Spectroscopic Explorer (MUSE) effort aimed at characterizing the surroundings of a sample of 5.7<z<6.6 quasars, which we have dubbed the Reionization Epoch QUasar InvEstigation with MUSE (REQUIEM) survey. We here present results of our searches for extended Ly{alpha} halos around the first 31 targets observed as part of this program. Reaching 5{sigma} surface brightness limits of 0.1-1.1x10^-17^erg/s/cm^2^/arcsec^2^ over a 1arcsec^2^ aperture, we were able to unveil the presence of 12 Ly{alpha} nebulae, eight of which are newly discovered. The detected nebulae show a variety of emission properties and morphologies with luminosities ranging from 8x10^42^ to 2x10^44^erg/s, FWHMs between 300 and 1700km/s, sizes <30pkpc, and redshifts consistent with those of the quasar host galaxies. As the first statistical and homogeneous investigation of the circumgalactic medium of massive galaxies at the end of the reionization epoch, the REQUIEM survey enables the study of the evolution of the cool gas surrounding quasars in the first 3Gyr of the universe. A comparison with the extended Ly{alpha} emission observed around bright (M_1450_<~-25mag) quasars at intermediate redshift indicates little variations on the properties of the cool gas from z~6 to z~3, followed by a decline in the average surface brightness down to z~2.
- ID:
- ivo://CDS.VizieR/J/A+A/437/789
- Title:
- Restframe I-band light curves of SN Ia
- Short Name:
- J/A+A/437/789
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a novel technique for fitting restframe I-band light curves on a data set of 42 type Ia supernovae (SNe Ia). Using the result of the fit, we construct a Hubble diagram with 26 SNe from the subset at 0.01<z<0.1. Adding two SNe at z~0.5 yields results consistent with a flat Lambda-dominated "concordance universe'' (Omega_M_,Omega_Lambda_)=(0.25, 0.75). For one of these, SN 2000fr, new near infrared data are presented. The high redshift supernova NIR data are also used to test for systematic effects in the use of SNe Ia as distance estimators. A flat, Lambda=0, universe where the faintness of supernovae at z~0.5 is due to grey dust homogeneously distributed in the intergalactic medium is disfavoured based on the high-z Hubble diagram using this small data-set. However, the uncertainties are large and no firm conclusion may be drawn. We explore the possibility of setting limits on intergalactic dust based on B-I and B-V colour measurements, and conclude that about 20 well measured SNe are needed to give statistically significant results. We also show that the high redshift restframe I-band data points are better fit by light curve templates that show a prominent second peak, suggesting that they are not intrinsically underluminous.
- ID:
- ivo://CDS.VizieR/VII/219
- Title:
- Revised Flat Galaxy Catalogue (RFGC)
- Short Name:
- VII/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Flat Galaxy Catalog (FGC) is the result of a systematic search for disk-like edge-on galaxies with a diameter larger than a=40arcsec and major-to-minor axis ratio a/b>7 from Palomar Observatory and ESO/SERC surveys; it contained 4455 objects covering about 56% of the whole sky (Karachentsev et al., 1993AN....314...97K, see Cat. <VII/162>). The main reasons for preparing a new, improved and supplemented catalogue version were the following: - a possibility of remeasuring the coordinates of flat galaxies with a higher accuracy using the Digital Sky Survey; - the inclusion the data about "red" galaxy diameters which were absent earlier; - a reduction the diameters measured on the J and R films of the ESO/SERC to the diameter system of the POSS-I (near to a_25_ system) that eliminated the difference in photometric depth between two parts of the catalogue (Kudrya et al. 1997PAZh...23...15K); - a calculation of total apparent magnitudes (with a standard error about 0.25mag) for all flat galaxies basing on angular diameters, surface brightnesses, and other parameter data (Kudrya et al. 1997PAZh...23..730K); - a possibility to determine the Galaxy absorption values in the region of each flat galaxy placing using new IR data (Schlegel et al. 1998ApJ...500..525S). - a necessity to remove the faults noted during the work with the FGC data. The structural differences between old and new catalogue versions are: - both the parts, FGC and FGCE, have been joined in the RFGC (Revised Flat Galaxy Catalogue) where the galaxies are ranged according to their Right Ascensions for the epoch J2000.0; - the Addendum have been omitted; - the Notes describing concrete object characteristics have been included in the main corpus of the catalogue, some details were omitted; - the lists of identification of the FGC and the FGCE galaxies have been omitted because these data are accessible now due to different galaxy databases (NED, LEDA etc).
