- ID:
- ivo://CDS.VizieR/J/MNRAS/318/333
- Title:
- Extended ROSAT Bright Cluster Sample
- Short Name:
- J/MNRAS/318/333
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a low-flux extension of the X-ray-selected ROSAT Brightest Cluster Sample (BCS) published in Paper I of this series. Like the original BCS and employing an identical selection procedure, the BCS extension is compiled from ROSAT All-Sky Survey (RASS) data in the northern hemisphere ({delta}>=0{deg}) and at high Galactic latitudes (|b|>=20{deg}). It comprises 99 X-ray-selected clusters of galaxies with measured redshifts z<=0.3 (as well as eight more at z>0.3) and total fluxes between 2.8x10^-12^ and 4.4x10^-12^erg/cm^2^/s in the 0.1-2.4keV band (the latter value being the flux limit of the original BCS). The extension can be combined with the main sample published in 1998 to form the homogeneously selected extended BCS (eBCS), the largest and statistically best understood cluster sample to emerge from the RASS to date. The nominal completeness of the combined sample (defined with respect to a power-law fit to the bright end of the BCS logN-logS distribution) is relatively low at 75per cent (compared with 90per cent for the high-flux sample of Paper I). However, just as for the original BCS, this incompleteness can be accurately quantified, and thus statistically corrected for, as a function of X-ray luminosity and redshift. In addition to its importance for improved statistical studies of the properties of clusters in the local Universe, the low-flux extension of the BCS is also intended to serve as a finding list for X-ray-bright clusters in the northern hemisphere which we hope will prove useful in the preparation of cluster observations with the next generation of X-ray telescopes such as Chandra and XMM-Newton.
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- 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/MNRAS/306/857
- Title:
- ROSAT Brightest Cluster Sample. III.
- Short Name:
- J/MNRAS/306/857
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new spectra of dominant galaxies in X-ray-selected clusters of galaxies, which combine with our previously published spectra to form a sample of 256 dominant galaxies in 215 clusters. 177 of the clusters are members of the ROSAT Brightest Cluster Sample (BCS; Ebeling et al., 1998MNRAS.301..881E), and 17 have no previous measured redshift. This is the first paper in a series correlating the properties of brightest cluster galaxies and their host clusters in the radio, optical and X-ray wavebands.
- ID:
- ivo://CDS.VizieR/J/MNRAS/341/1093
- Title:
- The Southern SHARC catalogue
- Short Name:
- J/MNRAS/341/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Southern Serendipitous High-redshift Archival Cluster (SHARC) catalogue is a X-ray selected catalogue of galaxy clusters detected in deep ROSAT observations. The survey area is 17.7deg^2^ and is selected from long (greater than 10ks) ROSAT exposures with a declination <+20deg and excluding the Galactic plane (excluding galactic latitudes within the range [-20,20]deg). Optical follow-up was performed to confirm the presence of a galaxy cluster and measure its redshift. The final catalogue contains 32 galaxy clusters with redshifts between 0.05 and 0.70 and X-ray luminosities between 7x10^35^W and 4x10^37^W. Above a redshift of 0.3 - which forms the primary subsample of the survey - there are 16 clusters; the X-ray luminosities of these clusters are all greater than 2x10^36 W. All X-ray luminosities are quoted in the 0.5-2.0keV band and were calculated using an Einstein-de Sitter cosmology with H_0_ set to 50km/s/Mpc.
