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RASSHGSOFT - ROSAT All-Sky Survey: Soft High Galactic-Latitude X-Ray Sources

HEASARC
Archive

Overview

A summary of spectroscopic identifications is presented for a complete sample of bright, soft, high galactic-latitude X-ray sources drawn from the ROSAT All-Sky Survey (RASS) which have PSPC count-rates CR>0.5cts/s, hardness ratios HR1<0, and galactic latitudes |b| > 20 degrees. Out of a total of 397 sources, 270 had previously catalogued counterparts, although most of these were not previously known as X-ray sources; of the remaining 127 sources neither X-ray nor optical properties were previously known. Of the whole sample of very soft X-ray sources 155 were also discovered by the Wide-Field-Camera on board ROSAT. Spectroscopic identifications are presented for 108 sources and other identifications for a further 18 sources; 1 source remains unidentified so far. In practically all cases a unique optical counterpart exists, facilitating identification. The largest source classes are AGN, magnetic cataclysmic variables, and hot white dwarfs

Catalog Bibcode

1998A&A...335..467T

References

Thomas H.-C., Beuermann K., Reinsch K., Schwope A.D., Truemper J., and Voges W. 1998, Astronomy & Astrophysics, 335, 467.

Provenance

This database was created by the HEASARC in April 1999 based on tables provided by the authors to CDS/ADC.

count rate err

The uncertainty in the PSPC count rate.

hardness ratio err

The uncertainty in the hardness ratio HR1.

Parameters

Rxs
The 1RXS designation: this is the name of the X-ray source in the RASS Bright Source Catalog (BSC) derived from its epoch 2000 position.

Name
The name of the optical counterpart to the X-ray source: notice that this information is provided only for the 270 of the 397 sources that had previously catalogued counterparts.

Source_Type
A specific type classification of the optical counterpart: this is generally the spectral type for stellar counterparts, and for extragalactic objects is generally the galaxy type, e.g Sy 1 for seyfert Type 1, BL for BL Lac, QSO for quasi-stellar object. In addition to these source types, the following others are also used:

  Source_type  Meaning

  PN           Planetary Nebula
  AM           AM Her-type CV
  SSS          Super-Soft Source
  LMXB         Low-Mass X-Ray Binary
  WD           White Dwarf
  

Offset
The angular separation between the optical and X-ray positions, in arcseconds.

Offset_Sigma
The angular separation between the optical and X-ray positions, in units of the 90% confidence radii r_90 of the X-ray source, where r90 is derived from the 1-sigma positional error delta_p given in the RASS BSC by r_90 = 1.65 * delta_p.

RA
The right ascension of the X-ray source in the selected equinox, derived by the HEASARC from the 1RXS designation (notice that this designation was based on J2000 equinox co-ordinates in the original input table). Assuming that the catalog creators followed the standard IAU procedure, this co-ordinate has been truncated to the nearest 0.1 seconds.

Dec
The declination of the X-ray source in the selected equinox, derived by the HEASARC from the 1RXS designation (notice that this designation was based on J2000 equinox co-ordinates in the original input table). Assuming that the catalog creators followed the standard IAU procedure, this co-ordinate has been truncated to the nearest arcsecond.

LII
The galactic longitude of the X-ray source.

BII
The galactic latitude of the X-ray source.

RA2000_Optical
The right ascension of the optical counterpart in the J2000 equinox: notice that this information is not provided for the 270 of the 397 sources that had previously catalogued counterparts.

Dec2000_Optical
The declination of the optical counterpart in the J2000 equinox: notice that this information is not provided for the 270 of the 397 sources that had previously catalogued counterparts.

Count_Rate
The mean PSPC count-rate as measured during the RASS, and as quoted in the RASS BSC: notice that this information is not provided for the 270 of the 397 sources that had previously catalogued counterparts, but can be found in the RASSBSC Catalog (q.v.).

Count_Rate_Error
rms uncertainty in count rate

Hardness_Ratio
The mean hardness ratio HR1 as measured during the RASS, and as quoted in the RASS BSC: notice that this information is not provided for the 270 of the 397 sources that had previously catalogued counterparts, but can be found in the RASSBSC Catalog (q.v.). This parameter is defined in the RASS by HR1 = (H-S)/(H+S) where S and H are the PSPC count rates in the energy bands of 0.1-0.5 keV and 0.5-2.0 keV, respectively.

Hardness_Ratio_Error
rms uncertainty in HR1

Broad_Class
A broad classification of the optical counterpart as either AGN, CV, QSO, WD (white dwarf), or star: notice that this information is not provided for the 270 of the 397 sources that had previously catalogued counterparts.

Redshift
The redshift of the optical counterpart, if extragalactic (and known).

Flag_Redshift
An uncertainty flag for the redshift z that is set to ':' if the redshift is regarded as uncertain.

Vmag
The visual (V) magnitude of the optical counterpart.

Notes
Notes on the object, mostly giving references, according to the following key:

            1: spectroscopic identification, this catalog
            2: WFC identification (Pye et al., 1995, Cat. <J/MNRAS/274/1165>,
                Mason et al., 1995, Cat. <J/MNRAS/274/1194>)
            3: Hamburg/RASS identification (Bade et al., 1998A&AS..127..145B)
            4: Grupe et al., 1998A&A...330...25G
            5: inferred identification from the Digitized Sky Survey
                (see Sect. 3.2)
            6: radio source (see Sect. 3.2)
            7: blank field
            8: Remarks to individual sources in notes.dat file: the latter is
               available either at the CDS or ADC, or at:
               ftp://legacy.gsfc.nasa.gov/heasarc/dbase/misc_files/rasshgsoft/
            9: Remarks for 3 individual sources from Table 2 of the original
               paper (Thomas et al., 1998A&A...335..467T) that this catalog is
               derived from: 1RXS J035025.0+171455 (V471 Tau): HR1=-0.7, white
               dwarf companion (Werner & Rauch, 1997A&A...324L..25W and
               references therein),
               1RXS J041521.5-073843 (40 Eri): HR1=-0.3, white dwarf companion,
               and 1RXS J132511.6-110932 (Spica): HR1=-0.9, coronal emission
               (Cassinelli et al., 1994ApJ...421..705C)
  

Class
The HEASARC browse classification, based on the value of the broad_class and (if available) the source_type parameters.


Contact Person

Questions regarding the RASSHGSOFT database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 8-Nov-2004