- ID:
- ivo://nasa.heasarc/rassnorsam
- Title:
- ROSAT All-Sky Survey Completely Identified Northern Sample
- Short Name:
- RASS/North
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a completely identified sample of northern ROSAT All-Sky Survey (RASS) X-ray sources, as well as some additional X-ray sources which either had count rates below the adopted limits or were located outside the boundaries of the study areas. It is a catalog of optical identifications of a representative sample of northern (declination > -9 degrees) RASS sources. A full identification has been carried out for a count-rate- and area-limited complete RASS subsample comprising 674 sources. All sources are within six study areas outside the galactic plane (absolute galactic latitude |b| > 19.6 degrees), one area being near the North Galactic Pole and one near the North Ecliptic Pole. This table was created by the HEASARC in August 2003 based on CDS tables J/ApJS/117/319/table1.dat.gz and J/ApJS/117/319/table2.dat.gz. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/rass6dfgs
- Title:
- ROSAT All-Sky Survey/6dF Galaxy Survey Catalog of X-Ray Selected AGN
- Short Name:
- RASS6DFGS
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of 3405 X-ray sources from the ROSAT All Sky Survey (RASS) Bright Source Catalog which fall within the area covered by the 6dF Galaxy Survey (6dFGS). The catalog is count-rate limited at 0.05 ct s<sup>-1</sup> in the X-ray and covers the area of sky with Declination < 0 degrees and |b| > 10 degrees. The RASS-6dFGS sample was one of the additional target catalogs of the 6dFGS and as a result the authors obtained optical spectra for 2224 (65 per cent) RASS sources. Of these, 1715 (77%) have reliable redshifts with a median redshift of z = 0.16 (excluding the Galactic sources). For the optically bright sources (b_J <= 17.5) in the observed sample, over 90% have reliable redshifts. The catalog mainly comprises quasi-stellar objects (QSOs) and active galaxies but also includes 238 Galactic sources. Of the sources with reliable redshifts, the majority are type 1 active galactic nuclei (AGN, 69%), while 12% are type 2 AGN, 6% absorption-line galaxies and 13% are stars. The authors also identify a small number of optically faint, very low redshift, compact objects which fall outside the general trend in the b_J - z plane. The RASS-6dFGS catalog complements a number of Northern hemisphere samples, particularly the ROSAT Bright Source Catalogue-NRAO VLA Sky Survey (RBSC-NVSS) sample (Bauer et al. 2000, ApJS, 129, 547), and furthermore, in the same region of sky (-40 degrees < Declination < 0 degrees) reveals an additional 561 sources that were not identified as part of that sample. The authors detect 918 sources (27%) of the RASS-6dFGS sample in the radio using either the 1.4 GHz NVSS or the 843 MHz Sydney University Molonglo Sky Survey (SUMSS) catalogues and find that the detection rate changes with redshift. At redshifts larger than 1 virtually all of these sources have radio counterparts and with a median flux density of 1.15 Jy, they are much stronger than the median flux density of 28.6 mJy for the full sample. The authors attribute this to the fact that the X-ray flux of these objects is being boosted by a jet component, possibly Doppler boosted, that is only present in radio-loud AGN. The RASS-6dFGS sample provides a large set of homogeneous optical spectra ideal for future studies of X-ray emitting AGN. This table was created by the HEASARC in April 2010 based on an electronic version of Table 3 from the reference paper obtained from the MNRAS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassebcs
- Title:
- ROSAT All-Sky Survey Extended Brightest Cluster Sample
- Short Name:
- RASSBCS
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the ROSAT All-Sky Survey (RASS) Brightest Cluster Sample (BCS) and the Low-Flux Extension, which together form the Extended BCS (eBCS). The main BCS, which was presented in Ebeling et al. (1998, MNRAS, 301, 881; Paper I), is a 90% flux-complete sample of the 201 X-ray-brightest clusters of galaxies in the northern hemisphere (Dec >=0 degrees), at high Galactic latitudes (|b| >= 20 degrees), with measured redshifts z <= 0.3 and X-ray fluxes higher than 4.4 x 10<sup>-12</sup> erg/cm<sup>2</sup>/s in the 0.1 - 2.4 keV band. This sample, called the ROSAT Brightest Cluster Sample, is selected from RASS data and is the largest X-ray-selected cluster sample compiled to the publication date (1998). In addition to Abell clusters which form the bulk of the sample, the BCS also contains the X-ray-brightest Zwicky clusters and other clusters selected from their X-ray properties alone. Effort has been made to ensure the highest possible completeness of the sample and the smallest possible contamination by non-cluster X-ray sources. X-ray fluxes were computed using an algorithm tailored for the detection and characterization of X-ray emission from galaxy clusters. These fluxes are accurate to better than 15% (mean 1-sigma error). The low-flux extension of the X-ray-selected ROSAT Brightest Cluster Sample was published in Ebeling et al. (2000, MNRAS, 318, 333; Paper IV). 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 (Dec >=0 degrees) and at high Galactic latitudes (|b| >= 20 degrees). 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 2.8 x 10<sup>-12</sup> and 4.4 x 10<sup>-12</sup> erg/cm<sup>2</sup>/s in the 0.1 - 2.4keV band (the latter value being the flux limit of the original BCS). The extension can be combined (as it has been in this HEASARC table) 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 log N -log S distribution) is relatively low at 75% (compared with 90% 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 the authors hoped will prove useful in the preparation of cluster observations to be made with the next generation of X-ray telescopes such as Chandra and XMM-Newton. This table was created by the HEASARC in August 2005 based on the merger of 2 CDS tables, J/MNRAS/301/881/table3.dat.gz (the main sample) and J/MNRAS/318/333/table1.dat.gz (the low-flux extension). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassfsc
- Title:
- ROSAT All-Sky Survey: Faint Sources
- Short Name:
- RASS/FSC
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The ROSAT All-Sky Survey Faint Source Catalog (RASS-FSC) was first released by the Max-Planck-Institut fuer extraterrestrische Physik, Garching group (voges et al. 2000) in May 2000. It is derived from the All-Sky Survey performed during the ROSAT mission using the Position-Sensitive Proportional Counter (PSPC) in the energy range 0.1 to 2.4 keV. Over one hundred thousand (105,924 to be exact) sources are catalogued herein, representing the faint extension of the RASS Bright Source Catalog (RASS-BSC, cf. IAU Circular 6420 and Voges et al. 1999, A&A, 349, 389: this is also available at the HEASARC as the RASSBSC database). The sources in this catalog have a detection likelihood of at least seven, and contain at least six source photons. The likelihood L of source detection is defined as L = -ln (1 - P), where P = the probability of source detection. For each source, the ROSAT name, position and positional error, the source count rate and error, the background count rate, the exposure time, the date of observation, two hardness ratios and their associated errors, the source extent and the extent likelihood, and the likelihood of source detection are given, inter alia. This HEASARC database was created in July 2000 based on the May 26 2000 release of the ROSAT All-Sky Survey Faint Source Catalog obtained from the Max-Planck-Institut fuer extraterrestrische Physik, Garching Website: <a href="http://www.xray.mpe.mpg.de/rosat/survey/rass-fsc/">http://www.xray.mpe.mpg.de/rosat/survey/rass-fsc/</a> This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassgiant
- Title:
- ROSATAll-SkySurvey:Giants&Supergiants
- Short Name:
- RASS/Giant
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The ROSAT All-Sky Survey Catalogue of Optically Bright Late-Type Giant and Supergiant Stars contains X-ray data for all late-type (spectral types of A through M, inclusive) giants and supergiants (luminosity classes of I through III-IV, inclusive) listed in the Bright Star Catalogue (BSC) that have been detected in the ROSAT All-Sky Survey. The RASS giants and supergiants catalog contains 450 entries of X-ray emitting, evolved late-type stars, which corresponds to an average detection rate of 11.7 percent. For each star, the ROSAT PSPC count rate, the hardness ratio, the apparent X-ray flux (calculated using an individual energy-conversion-factor based on the hardness ratio), and the ratio of X-ray to bolometric flux are given. The full details of the data selection, the source detection criteria, etc., are given in the paper by Huensch, Schmitt and Voges (1998, A&AS, 127, 251) describing this catalog; essentially for a star to be identified as an X-ray source, the X-ray source had to have at least a 99.9 percent existence probability, corresponding to a likelihood of greater than or equal to 7, and lie within 90 arcseconds of the optical position. Given the number of sky locations examined and the total number of RASS sources, it is expected that of order 27.4 of the 450 claimed associations in this catalog will be chance coincidences. This database was created at the HEASARC in July 1998 based on the ADC/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+AS/127/251">CDS Catalog J/A+AS/127/251</a>. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/hyadesxray
- Title:
- ROSAT All-Sky Survey: Hyades Cluster Region
- Short Name:
- RASS/Hyades
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog contains the results of a complete X-ray survey of the Hyades cluster region using X-ray data from the ROSAT All-Sky Survey (RASS) that was published by Stern, Schmitt and Kahabka in 1995. The Hyades survey covered over 900 square degrees of the sky. Over 185 optically identified Hyades were detected down to a limiting X-ray luminosity of about 1-2x10<sup>28</sup> ergs/s in the 0.1-1.8keV energy band. Among solar-like stars, i.e., main-sequence stars of spectral type G, the RASS detection rate was about 90%. Stern et al. argue that the presence of many binary systems in the cluster is a key factor influencing the Hyades X-ray luminosity function. Short-period (a few days or less) binaries are anomalously X-ray bright, as might have been expected; however, the X-ray luminosity functions of K and possibly M binary stars of all types are significantly different from their single counterparts, confirming the results of Pye et al. (1994, MNRAS, 266, 798) based on a smaller K star sample drawn from deep ROSAT pointings. Comparison with Einstein Observatory studies of a subset of Hyades stars demonstrates a general lack of significant (> a factor of 2) long-term X-ray variability. Stern et al. suggest that this may be the result of the dominance of a small-scale, turbulent dynamo in the younger Hyades stars compared to the large-scale, cyclic dynamo observed in the Sun. The HYADESXRAY database consists of X-ray data for 440 probable and possible Hyades members that were included in the Stern et al. survey and were listed in Table 1 of their published paper. The database contains both stars which were detected as X-ray sources and those which were not: for the latter, upper limits to their X-ray emission are provided. For all listed stars, their X-ray luminosities based on a Hyades distance of 45 pc are provided; for some stars, for which individually determined distances from either the Schwan (1991, A&A, 243, 386) or the Hanson (1975, AJ, 80, 379) proper motion surveys are available, their X-ray luminosities based on these alternate distances are also provided. There were 4 stars detected as RASS sources out of over 180 new Hyades candidates listed in the Reid (1992, MNRAS, 257, 257) proper motion survey which were included in Table 2 (but not Table 1) of the Stern et al. paper. These stars are not included in the current database, but are listed in the help section entitled Reid_Stars (q.v.). Similarly, there were 20 stars detected as RASS sources but which were considered by Stern et al. to be non-members of the Hyades which were included in their Table 3 (but not Table 1). These stars are not included in the current database, but are listed in the help section entitled Rejected_Hyades (q.v.). This HEASARC catalog was created in July 1997, derived from <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/448/683">CDS Catalog J/ApJ/448/683</a> obtained from <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/448/683/">https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/448/683/</a>. Additional information provided in the HEASARC documentation was taken from the original published version of the paper containing this catalog. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rasscns3
- Title:
- ROSAT All-Sky Survey: Nearby Stars
- Short Name:
- RASS/CNS3
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog presents X-ray data for all entries in the Third Catalogue of Nearby Stars (CNS3: Gliese and Jahreiss, 1991, ADC/CDS Cat. <V/70>) that have been detected as X-ray sources in the ROSAT All-Sky Survey (RASS). The catalog contains 1252 entries, yielding an average detection rate of 32.9 percent of the 3802 CNS3 stars. In addition to count rates, source detection parameters, X-ray hardness ratios, and X-ray fluxes, X-ray luminosities derived from Hipparcos parallaxes are also listed. For a star to have been considered by the authors to have been detected as an X-ray source in the RASS, an X-ray source with an existence likelihood of 7 or more (equivalent to a source existence probablity of 99.9 percent or more) had to lie within 90 arcseconds of its 1990 epoch CNS3 position. The choice of this cut-off radius was based on a Monte Carlo simulation of about the same number of random positions that were used as input positions. At an offset of 90 arcseconds between the optical and X-ray positions the probability that the X-ray source is attributable to the star and not to a unrelated background object is 50 percent; this probability increases very rapidly for smaller values of the offset, notice. This database was created in June 1999 based on tables provided by the ADC/CDS data centers supplemented by additional tabular material provided to the HEASARC by the author Dr. M. Huensch. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rbscnvss
- Title:
- ROSAT All-Sky Survey/NVSS Bright X-Ray Source Sample
- Short Name:
- RASS/NVSS
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- By cross-identifying the RASS (ROSAT All-Sky Survey) Bright Source Catalog (RBSC, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/IX/10">CDS Catalog IX/10</a>) with the NRAO VLA Sky Survey (NVSS, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VIII/65">CDS Catalog VIII/65</a>), the authors have constructed the RBSC-NVSS sample of the brightest X-ray sources (>= 0.1 counts/s ~ 10<sup>-12</sup> erg/cm<sup>2</sup>/s in the 0.1 - 2.4keV band) that are also radio sources (S >= 2.5 mJy at 1.4 GHz) in the 7.8 sr solid angle of extragalactic sky with galactic latitude |b| > 15 degrees and declination > -40 degrees. The sky density of NVSS sources is low enough that they can be reliably identified with RBSC sources having rms positional uncertainties >= 10". The authors used the more accurate radio positions to make reliable X-ray/radio/optical identifications down to the POSS plate limits. They obtained optical spectra for many of the bright identifications lacking published redshifts. The resulting X-ray/radio sample is unique in its size (1557 objects), composition (a mixture of nearly normal galaxies, Seyfert galaxies, quasars, and clusters), and low average redshift [<z>~0.1]. This table was created by the HEASARC in September 2003 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/129/547">CDS Catalog J/ApJS/129/547</a>, files table1.dat and table2.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassob
- Title:
- ROSAT All-Sky Survey: OB Stars
- Short Name:
- RASS/OB
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- For detailed statistical analysis of the X-ray emission of hot stars, stars of spectral type O and B listed in the Yale Bright Star Catalogue were selected and searched for in the ROSAT All-Sky Survey. This database table displays a compilation of the derived X-ray data for a complete sample of bright OB stars. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassfirst
- Title:
- ROSAT All-Sky Survey Single FIRST Matches Catalog
- Short Name:
- RASSFIRST
- Date:
- 28 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a subset of the results of a correlation of the ROSAT All-Sky Survey (RASS) with the April 1997 release of the VLA 20-cm Faint Images of the Radio Sky at Twenty cm (FIRST: <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VIII/59">CDS Cat. <VIII/59></a>) Catalog. It focusses on the analysis of 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 the authors obtain new spectroscopic classifications for 85 sources by comparison with the ongoing FIRST Bright Quasar Survey and 106 additional sources from their 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. In their paper (Table 2), the authors 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, they do not consider these data in the current analysis, and they are not included in the present table (but are available at <a href="http://cdsarc.u-strasbg.fr/ftp/cats/J/A+A/356/445/">http://cdsarc.u-strasbg.fr/ftp/cats/J/A+A/356/445/</a>). This table was created by the HEASARC in March 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/356/445">CDS Catalog J/A+A/356/445</a> file table1.dat, the list of ROSAT All-Sky Survey sources with single FIRST matches. This is a service provided by NASA HEASARC .
