HRASSCAT - Hamburg/RASS Catalog: X-Ray Sources
This table is a representation of part of the Hamburg/ROSAT All-Sky
Survey (RASS) Catalog (HRC) of optical identifications of X-ray sources at
high-galactic latitude, namely the list of X-ray sources. (The list of proposed
and possible optical counterparts is given in the linked Browse table
HRASSOPTID). The HRC includes all X-ray sources from the ROSAT
Bright Source Catalog (RASS-BSC) with galactic latitude |b| >= 30 degrees and
declination Dec >= 0 degrees. In this part of the sky covering ~10,000 square
degrees, the RASS-BSC contains 5341 X-ray sources. For the optical
identification, the HRC authors used blue Schmidt prism and direct plates
taken for the northern hemisphere Hamburg Quasar Survey (HQS) which are now
available in digitized form. The limiting magnitudes are 18.5 and 20,
respectively. For 82% of the selected RASS-BSC, an identification could be
given. For the rest, either no counterpart was visible in the error circle,
or a plausible identification was not possible. With ~42%, AGN represent
the largest group of X-ray emitters, ~31% have a stellar counterpart, whereas
galaxies and cluster of galaxies comprise only ~4% and ~5%, respectively. In
~3% of the RASS-BSC sources, no object was visible on the blue direct plates
within 40" around the X-ray source position. The catalog has been used as
a source for the selection of (nearly) complete samples of the various
classes of X-ray emitters.
The Hamburg/RASS Catalogue of optical identifications.
Northern high-galactic latitude ROSAT Bright Source Catalogue X-ray sources.
Zickgraf F.-J., Engels D., Hagen H.-J., Reimers D., Voges W.
<Astron. Astrophys. 406, 535 (2003)>
This table was produced by the HEASARC in February 2005 based
on the CDS Catalog table J/A+A/406/353/x-ray.dat.
This table is the Version 3.0 of the HRC, issued on May 6,
2003, and containing 5341 X-ray sources from the ROSAT-BSC. Version 2.0,
issued on January 5, 1998 had 4665 positions (Bade et al., 1998, CDS Cat.
<J/A+AS/127/145>). Version 1.1, issued on December 5, 1996, had additional
entries in the X-ray rows (flags and the date of last change). Version 1.0
was issued on November 1, 1996.
The catalog can be used for scientific purposes if the paper listed
in the References section is referenced. For more detailed information about
the identification code and the classification scheme for objective prism
spectra, the catalog user is also referred to this paper.
The ROSAT project is supported by the Ministerium fuer
Bildung, Wissenschaft, Forschung und Technologie (BMBF/DARA) and by the
The research on which this table is based made use of the NASA/IPAC
Extragalactic Database (NED) which is operated by the Jet Propulsion
Laboratory, California Institute of Technology, under contract with
the National Aeronautics and Space Administration. It has been funded
by the Deutsche Forschungsgemeinschaft under Re 353/22-1 to 4 and by
the BMBF under DARA 50 0R 96016.
The STScI Digitized Sky Surveys were produced at the Space Telescope
Science Institute under U.S. Government grant NAG W-2166. The images
of these surveys are based on photographic data obtained using the
Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt
Telescope. The plates were processed into the present compressed
digital form with the permission of these institutions.
The National Geographic Society - Palomar Observatory Sky Atlas
(POSS-I) was made by the California Institute of Technology with
grants from the National Geographic Society.
The 1RXS catalog designation.
The RASS PSPC count rate, in counts/s.
The error in the RASS PSPC count rate, in counts/s.
The hardness ratio, HR1, of the X-ray source, defined as
HR1 = (B - A)/(B + A)
where A is the count rate in the 0.11 - 0.41 keV energy band and B is the
count rate in the 0.52 - 2.01 keV energy band.
The error in the hardness ratio, HR1.
The hardness ratio, HR2, of the X-ray source, defined as
HR2 = (D - C)/(D + C)
where C is the count rate in the 0.52 - 0.90 keV energy band and D is the
count rate in the 0.91 - 2.01 keV energy band.
The error in the hardness ratio, HR2.
The X-ray source extension, in arcseconds.
The X-ray source extension likelihood.
The RASS designation, RX JHHMM.m+DDMM, as used in the first
Version of this catalog.
The Right Ascension of the X-ray source in the selected equinox.
This was given in J2000.0 coordinates and to a precision of 0.1 seconds
of time in the originating CDS table.
The Declination of the X-ray source in the selected equinox.
This was given in J2000.0 coordinates and to a precision of 1 arcsecond
in the originating CDS table.
The Galactic Longitude of the X-ray source.
The Galactic Latitude of the X-ray source.
The nominal X-ray source 90% error radius in arcseconds
as provided by the SASS processing.
An internal identifying number for the X-ray source in
the Hamburg-RASS Catalog Data Base. Every X-ray source in the catalog has
a unique values of the Sequence_Number parameter.
An identification code defined as follows: the first (and third)
digit(s) give(s) the type classification:
2 Galaxy, derived from the morphology on the direct plates
3 Galaxy Cluster
5 M Star
6 White Dwarf
7_1 K Star
7_2 F or G Star
7_3 Cataclysmic Variable (CV)
7_4 Bright Star (B < 13)
8 No (unambiguous) identification, overlaps
803 No spectrum available for likely counterpart
0 No objects visible within a radius of 40 arcsec around the
X-ray position ("blank field")
The second digit in the identification code describes the reliability of
the given identification:
0 'highly probable', The proposed counterpart fulfills all requirements
of its class and no other plausible counterpart within the error radius
of the X-ray source exists
1 'probable', The proposed counterpart fulfills the requirements of
its class, but there are limitations. Either, the objective spectrum
is not typical, or there are small conflicts with the X-ray
information (spectral or spatial information, distance to the
X-ray position) or there is another (considerably less) plausible
counterpart in the error circle
2 'possible', The proposed counterpart fulfills some requirements of
its class, but there are doubts arising from insufficient objective
prism data, conflicting X-ray data or another plausible candidate
Thus, ID_Code = 711 implies that the object is a 'probable' K star.
A flag that, if set to 1, means that the identification has
changed since the last catalog version.
A flag that, if set to 1, indicates that the X-Ray position
has changed since the last catalog version.
A flag that is set to 1 for supplementary X-ray positions.
The date of the last change to any of the fields for the
specified X-ray source. According to the CDS ReadMe file for this catalog,
for the source 1RXS J123516.9+233447, the last digit of the date was missing,
and was replaced by 0. in their table, while, for the source
1RXS J081929.5+704221, and there are no values for the flags or date
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