- ID:
- ivo://CDS.VizieR/J/ApJ/511/595
- Title:
- An X-Ray Survey of Galaxies in Pairs
- Short Name:
- J/ApJ/511/595
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results are reported from the first survey of X-ray emission from galaxies in pairs. The sample consists of 52 pairs of galaxies from the Catalog of Paired Galaxies (Cat. <VII/77>) whose coordinates overlap the ROSAT Position Sensitive Proportional Counter pointed observations. The mean observed log(L_x_) for early-type pairs is 41.35+/-0.21, while the mean log(L_x_) predicted using the (L_X_-L_b_) relationship for isolated early-type galaxies is 42.10+/-0.19. With 95% confidence, the galaxies in pairs are underluminous in the X-ray, compared with isolated galaxies, for the same L_b_. A significant fraction of the mixed pair sample also appears similarly underluminous. A spatial analysis shows that the X-ray emission from pairs of both types typically has an extent of 10 - 50 kpc, much smaller than the group intergalactic medium, and thus likely originates from the galaxies. CPG 564, the most X-ray luminous early-type pair, 4.7x10^42^ergs/s, is an exception. The extent of its X-ray emission, greater than 169 kpc, and HWHM, {~}80 kpc, is comparable to that expected from an intergalactic medium. The sample shows only a weak correlation, {~}81% confidence, between L_X_ and L_b_, presumably due to variations in gas content within the galaxies. No correlation between L_X_ and the pair velocity difference ({delta}v), separation ({delta}r), or far-infrared luminosity (L_fir_) is found, although the detection rate is low, 22%.
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- ID:
- ivo://CDS.VizieR/J/ApJS/129/435
- Title:
- NORAS galaxy cluster survey. I.
- Short Name:
- J/ApJS/129/435
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the construction of an X-ray-selected sample of galaxy clusters for cosmological studies, we have assembled a sample of 495 X-ray sources found to show extended X-ray emission in the first processing of the ROSAT All-Sky Survey. The sample covers the celestial region with declination {delta}>=0{deg} and Galactic latitude |b|>=20{deg} and comprises sources with a count rate >=0.06counts/s and a source extent likelihood of L>=7. In an optical follow-up identification program we find 378 (76%) of these sources to be clusters of galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/311/456
- Title:
- RIXOS source catalogue
- Short Name:
- J/MNRAS/311/456
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the ROSAT International X-ray/Optical Survey (RIXOS), a medium-sensitivity survey and optical identification of X-ray sources discovered in ROSAT high Galactic latitude fields (|b|>280) and observed with the Position Sensitive Proportional Counter (PSPC) detector. We presents a catalogue of the RIXOS sources and their optical identifications.
- ID:
- ivo://CDS.VizieR/IX/29
- Title:
- ROSAT All-Sky Survey Faint Source Catalog
- Short Name:
- IX/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ROSAT All-Sky Survey Faint Source Catalogue (RASS-FSC) is derived from the all-sky survey performed during the ROSAT mission in the energy band 0.1-2.4 keV. 105,924 sources are catalogued and represent the faint extension to the RASS bright source catalogue (RASS-BSC, 1999A&A...349..389V, See Cat. <IX/10>). The sources have a detection likelihood of at least 7 and contain at least 6 source photons. (The likelihood of source detection is defined as L = -ln(1-P), with P = probability of source detection). For each source we provide the ROSAT name, the position in equatorial coordinates, the positional error, the source countrate and error, the background countrate, exposure time, date of observation, hardness-ratios HR1 and HR2 and errors, extent and likelihood of extent, and likelihood of detection. Questions or comments may be directed to xray-info(at)mpe.mpg.de
- 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/IX/28A
- Title:
- ROSAT HRI Pointed Observations (1RXH)
- Short Name:
- IX/28A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The hricat.dat table contains a list of sources detected by the Standard Analysis Software System (SASS) in reprocessed, public High Resolution Imager (HRI) datasets. In addition to the parameters returned by SASS (like position, count rate, signal-to-noise, etc.) each source in the table has associated with it a set of source and sequence "flags". These flags are provided by the ROSAT data centers in the US, Germany and the UK to help the user of the ROSHRI database judge the reliability of a given source. These data have been screened by ROSAT data centers in the US, Germany, and the UK as a step in the production of the Rosat Results Archive (RRA). The RRA contains extracted source and associated products with an indication of reliability for the primary parameters.
- ID:
- ivo://CDS.VizieR/J/ApJ/514/148
- Title:
- ROSAT survey of bright galaxies clusters
- Short Name:
- J/ApJ/514/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the selection of an X-ray flux-limited sample of bright clusters of galaxies in the southern hemisphere, based on the first analysis of the ROSAT All-Sky Survey data (RASS1). The sample is constructed starting from an identification of candidate clusters in RASS1, after which their X-ray fluxes are remeasured using the steepness-ratio technique. This method is better suited than the RASS1 standard algorithm to measuring flux from extended sources. The final sample is count-rate-limited in the ROSAT hard band (0.5-2.0 keV), so that as a result of the distribution of N_H_, its effective flux limit varies between {~}3 and 4x10^-12^ ergs cm^-2^ s^-1^ over the selected area. This covers the {delta} < 2.5{deg} part of the south Galactic cap region (b < -20{deg}), excluding patches of low RASS1 exposure time and of the Magellanic Clouds area, for a total of 8235 deg^2^. One hundred and thirty candidate sources fulfill our selection criteria for bona fide clusters of galaxies in this area. Of these, 101 are Abell/ACO clusters, while 29 do not have a counterpart in these catalogs. Of these clusters, 126 (97%) have a redshift, and for these we compute an X-ray luminosity. 20% of the cluster redshifts come from new observations, as part of the ESO Key Program survey of RASS clusters that is currently under completion. Considering the intrinsic biases and incompletenesses introduced by the flux selection and source identification processes, we estimate the overall completeness to be better than 90%. The observed number count distribution, log Nlog S, is well fitted by a power law with slope {alpha} =1.34{+/-}0.15 and normalization A=11.87{+/-}1.04 sr^-1^ (10^-11^ ergs cm^-2^ s^-1^)^{alpha}^, in good agreement with other measurements.
- ID:
- ivo://CDS.VizieR/J/A+A/371/833
- Title:
- ROSAT Ultra Deep Survey
- Short Name:
- J/A+A/371/833
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ROSAT Ultra Deep Survey in the Lockman Hole consists of a sample of 94 X-ray sources reaching a limiting flux of 1.2x10-15erg/s/cm^2^ in the 0.5-2.0keV energy band. About 90% of the X-ray sources have been spectroscopically identified using low-resolution Keck spectra.
- ID:
- ivo://CDS.VizieR/J/A+A/588/A103
- Title:
- Second ROSAT all-sky survey (2RXS) source catalog
- Short Name:
- J/A+A/588/A103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the second ROSAT all-sky survey source catalogue, hereafter referred to as the 2RXS catalogue. This is the second publicly released ROSAT catalogue of point-like sources obtained from the ROSAT all-sky survey (RASS) observations performed with the position-sensitive proportional counter (PSPC) between June 1990 and August 1991, and is an extended and revised version of the bright and faint source catalogues. We used the latest version of the RASS processing to produce overlapping X-ray images of 6.4 by 6.4 degrees sky regions. To create a source catalogue, a likelihood-based detection algorithm was applied to these, which accounts for the variable point-spread function (PSF) across the PSPC field of view. Improvements in the background determination compared to 1RXS were also implemented. X-ray control images showing the source and background extraction regions were generated, which were visually inspected. Simulations were performed to assess the spurious source content of the 2RXS catalogue. X-ray spectra and light curves were extracted for the 2RXS sources, with spectral and variability parameters derived from these products. We obtained about 135,000 X-ray detections in the 0.1-2.4keV energy band down to a likelihood threshold of 6.5, as adopted in the 1RXS faint source catalogue. Our simulations show that the expected spurious content of the catalogue is a strong function of detection likelihood, and the full catalogue is expected to contain about 30 per cent spurious detections. A more conservative likelihood threshold of 9, on the other hand, yields about 71,000 detections with a 5 per cent spurious fraction. We recommend thresholds appropriate to the scientific application. X-ray images and overlaid X-ray contour lines provide an additional user product to evaluate the detections visually, and we performed our own visual inspections to flag uncertain detections. Intra-day variability in the X-ray light curves was quantified based on the normalised excess variance and a maximum amplitude variability analysis. X-ray spectral fits were performed using three basic models, a power law, a thermal plasma emission model, and black-body emission. Thirty-two large extended regions with diffuse emission and embedded point sources were identified and excluded from the present analysis. The 2RXS catalogue provides the deepest and cleanest X-ray all-sky survey catalogue in advance of eROSITA.
- ID:
- ivo://CDS.VizieR/IX/30
- Title:
- Second ROSAT PSPC Catalog
- Short Name:
- IX/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains sources from PSPC-ROSAT (Position-Sensitive Proportional Counter aboard the Roentgen Satellite), as provided by Max-Planck Institut fuer extraterrestrische Physik (MPE). It supersedes the 1994 version (Cat. <IX/11>) The current release of the catalog is comprised of results from 4093 sequences (sky coverage of 14.5%). The complete version contains entries for 95,331 detections whereas the short version has 43,156 detections. 2189 obvious sources were not detected by the automated Standard Analysis Software System (SASS), and are not yet contained in this catalogue. These data have been screened by ROSAT data centers in the US, Germany, and the UK as a step in the production of the ROSAT RESULTS ARCHIVE. The RRA contains extracted source and associated products with an indication of reliability for the primary parameters.
