- 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.
Number of results to display per page
Search Results
702. ROSAT Bright Survey
- ID:
- ivo://CDS.VizieR/IX/32
- Title:
- ROSAT Bright Survey
- Short Name:
- IX/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ROSAT Bright Survey (RBS, table "rosat.dat") aims to completely optically identify the 2072 brightest sources detected in the ROSAT all-sky survey (Cat. <IX/10>) at galactic latitudes |b|>30{deg} (excluding LMC, SMC, Virgo cluster), with countrate above 0.2s^-1^; this program is 99.5% complete, and a sub-sample of 931 sources with countrate above 0.2s^-1^ in the hard spectral band between 0.5 and 2.0keV is 100% identified. The total survey area comprises 20391{deg}^2^ at a flux limit of 2.4x10^-12^erg/cm^2^/s in the 0.5-2.0keV band. Tables 1 and 3 examine the "RHS" sub-sample of 66 bright point-like ROSAT survey sources with almost hard PSPC spectra (hardness ratio HR1>0.5) which could be nearly completely identified by low-resolution optical spectroscopy with the following breakdown into object classes: 31 Seyfert galaxies (20 Sy1), 22 BL Lac candidates, 5 clusters of galaxies, 1 cataclysmic variable, and 5 bright stars. Only one object remained unidentified and one X-ray source was a spurious detection.
- ID:
- ivo://CDS.VizieR/J/A+A/378/30
- Title:
- ROSAT-BSC galaxy identifications
- Short Name:
- J/A+A/378/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a correlation study of the ROSAT All-Sky Survey Bright Source Catalogue (RASS-BSC, Cat. <XI/10>) with the Catalogue of Principal Galaxies (PGC, Cat. <VII/119>) 904 X-ray sources were found that possess possible extragalactic counterparts within a search radius of 100". File table1 contains 1124 optical galaxy entries and 904 relevant X-ray candidates/counterparts from the ROSAT All-Sky Survey. Besides a compilation of X-ray and optical parameters for each source, also the results of an identification screening are given. 547 optical/X-ray correlations have been quoted as reliable identifications. The 904 optical images with X-ray overlay contours (xID_nnn.ps.gz) used in the screening process are added for each user's own judgement.
- ID:
- ivo://CDS.VizieR/J/A+A/329/482
- Title:
- ROSAT Deep Survey in the Lockman Hole
- Short Name:
- J/A+A/329/482
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ROSAT Deep Survey in the Lockman Hole is the most sensitive X-ray survey performed to date, encompassing an exposure time of 207ksec with the PSPC and a total of 1.32Msec with the HRI aboard ROSAT. Here we present the complete catalogue of 50 X-ray sources with PSPC fluxes (0.5-2 keV) above 5.5x10^-15^erg/cm^2^/s.
- ID:
- ivo://CDS.VizieR/J/A+A/319/413
- Title:
- ROSAT detected quasars. I.
- Short Name:
- J/A+A/319/413
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a sample of all quasars with measured radio emission from the Veron-Cetty - Veron catalogue (1993, VV93 <VII/166>) detected by ROSAT in the ALL-SKY SURVEY (RASS, Voges 1992), as targets of pointed observations, or as serendipitous sources from pointed observations as publicly available from the ROSAT point source catalogue (ROSAT-SRC, Voges et al. 1995). The total number of ROSAT detected radio quasars from the above three sources is 654 objects. 69 of the objects are classified as radio-quiet using the defining line at a radio-loudness of 1.0, and 10 objects have no classification. The 5GHz data are from the 87GB radio survey, the NED database, or from the Veron-Cetty - Veron catalogue. The power law indices and their errors are estimated from the two hardness ratios given by the SASS assuming Galactic absorption. The X-ray flux densities in the ROSAT band (0.1-2.4keV) are calculated from the count rates using the energy to counts conversion factor for power law spectra and Galactic absorption. For the photon index we use the value obtained for a individual source if the estimated 1 sigma error is smaller than 0.5, otherwise we use the mean value 2.14.
- ID:
- ivo://CDS.VizieR/J/A+A/323/739
- Title:
- ROSAT detected quasars. II.
- Short Name:
- J/A+A/323/739
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the broad band, radio - to - X-ray, properties of a large sample of mostly previously optically unidentified radio-loud X-ray sources from the correlation of a ROSAT All-Sky Survey source list with the 5GHz Green Bank Survey of the northern sky (RGB sample) which is one of the largest well-defined flux-limited surveys of AGN ever obtained. Further, the RGB pushes 1-2 orders of magnitude deeper in both X-ray and radio flux compared to previous unbiased wide-area AGN surveys. Follow up VLA observations of the candidate objects yielded positions with arcsec accuracy which were used to find optical counterparts to the sources from digitized POSS plates. The sources are divided into three classes according to the positional offset between the X-ray and radio candidates and the spatial resolution of the radio observations, reflecting the various degrees of confidence about the correctness of the proposed association. Although the nature of the sources as well as their redshifts remain to be determined in spectroscopic follow up observations, the derived flux ratios lead to the conclusion that the majority of them are quasars. Hardly any correlations could be found between different source parameters, possibly due to the fact that most of the objects are found in a relatively small flux range near the sensitivity limit of the radio catalogue. The majority of the new RGB sources have broad-band properties between those of traditional radio-selected and X-ray selected AGN. There is no bimodal distribution in the radio-loudness distribution, and the traditional division between radio-quiet and radio-loud AGN may not be warranted.
- ID:
- ivo://CDS.VizieR/J/A+A/330/108
- Title:
- ROSAT detected quasars. II.
- Short Name:
- J/A+A/330/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a sample of all radio-quiet quasars or quasars without radio detection from the Veron-Cetty - Veron catalogue (1993, VV93, Cat. <VII/166>) detected by ROSAT in the ALL-SKY SURVEY (RASS, Voges 1992, in Proc. of the ISY Conference `Space Science', ESA ISY-3, ESA Publications, p.9, See Cat. <IX/10>), as targets of pointed observations, or as serendipitous sources from pointed observations publicly available from the ROSAT point source catalogue (ROSAT-SRC, Voges et al. 1995, Cat. <IX/11>). For all sources we used the results of the Standard Analysis Software System (SASS, Voges et al. 1992, in Proc. of the ISY Conference `Space Science', ESA ISY-3, ESA Publications, p.223), employing the most recent processing for the Survey data (RASS-II, Voges et al. 1996, Cat. <IX/10>). The total number of quasars is 846. 69 of the radio-quiet objects with radio detections have already been presented in a previous paper (Brinkmann, Yuan, & Siebert 1997, Cat. <J/A+A/319/413>) using the RASS-I results. 17 objects were found to be radio-loud from recent radio surveys and were marked in the table. When available, the power law photon indices and the corresponding absorption column densities (NH) were estimated from the two hardness ratios given by the SASS, both with free fitted NH and for Galactic absorption. The unabsorbed X-ray flux densities in the ROSAT band (0.1-2.4keV) were calculated from the count rates using the energy to counts conversion factor for power law spectra and Galactic absorption. As the photon index we used the value obtained for the individual source if the estimated 1-{sigma} error is smaller than 0.5, otherwise we used the redshift-dependent mean value (see the paper for details).
- ID:
- ivo://CDS.VizieR/J/A+A/356/445
- Title:
- ROSAT-FIRST AGN correlation
- Short Name:
- J/A+A/356/445
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a correlation of the ROSAT All-Sky Survey with the April 1997 release of the VLA 20cm FIRST (Cat. <VIII/59>) catalogue. We focus our analysis on the 843 X-ray sources which have unique radio counterparts. The majority of these objects (84%) have optical counterparts on the POSS 1 plates. Approximately 30% have been previously classified and we obtain new spectroscopic classifications for 85 sources by comparison with the ongoing FIRST Bright Quasar Survey and 106 additional sources from our own new spectroscopic data. Approximately 51% of the sources are presently classified, and the majority of the unclassified objects are optically faint. The newly classified sources are generally radio weak, exhibiting properties intermediate with previous samples of radio- and X-ray-selected AGN. This also holds for the subsample of 71 BL Lacs which includes many intermediate objects. The 146 quasars show no evidence for a bimodal distribution in their radio-loudness parameter, indicating that the supposed division between radio-quiet and radio-loud AGN may not be real. The X-ray and radio luminosities are correlated over two decades in radio luminosity, spanning the radio-loud and radio-quiet regimes, with radio-quiet quasars showing a linear correlation between the two luminosities. Many of the sources show peculiar or unusual properties which call for more detailed follow-up observations. We also give the X-ray and radio data for the 518 X-ray sources for which more than one radio object is found. Because of the difficulties inherent in identifying optical counterparts to these complex sources, we do not consider these data in the current analysis.
- ID:
- ivo://CDS.VizieR/J/A+AS/132/341
- Title:
- ROSAT GPS optical identification
- Short Name:
- J/A+AS/132/341
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on optical searches in the error circles of 93 ROSAT survey sources located at low galactic latitudes (|b|<20{deg}). These sources were extracted from the ROSAT Galactic Plane Survey using various selection criteria on hardness ratio, X-ray and optical brightness and integrated galactic absorption in the direction of the source. We find optical identifications in 76 cases, among which are 25 new AGN, 6 new CVs and a new Be/X-ray binary. In order to illustrate the relevance of the source selections applied here, we cross-correlated the ROSAT all-sky survey bright source list with SIMBAD. Different classes of X-ray emitters populate distinct regions of a multi dimensional parameter space involving flux ratios, galactic latitude and N_H_. This relatively good segregation offers the possibility to build source samples with enhanced probability of identification with a given class. Complete optical identification of such subsamples could eventually be used to compute meaningful probabilities of identification for all sources using as basis a restricted set of multi-wavelength information.
- ID:
- ivo://CDS.VizieR/J/A+AS/143/391
- Title:
- ROSAT HRI catalogue of LMC X-ray sources
- Short Name:
- J/A+AS/143/391
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ROSAT HRI LMC source catalogue is based on all 543 pointed observations of the ROSAT HRI between 1990 and 1998 with exposure times higher than 50 sec. The observations covered a 10 deg x 10 deg field including the LMC. The catalogue contains 397 X-ray sources. Sources showing flux variability in ROSAT HRI and PSPC are listed in Table 1. Table 2 contains HRI sources which were identified with known objects in other catalogues and literature. Table 3 is a list of new classifications. The whole source catalogue from HRI observations is given in Table 4.
