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RASSBSC - ROSAT All-Sky Survey: Bright Sources

HEASARC
Archive

Overview

The ROSAT All-Sky Survey Bright Source Catalogue (RASS-BSC, revision 1RXS) has been released and is available through the World Wide Web (URL http://www.xray.mpe.mpg.de/rosat/survey/rass-bsc/) and via anonymous ftp (ftp://ftp.xray.mpe.mpg.de/rosat/catalogues/rass-bsc/) (cf. IAU Circular No. 6420, June 19, 1996).

This catalogue is derived from the all-sky survey performed during the first half year of the ROSAT mission in 1990-1991; 18,811 sources are catalogued, with a limiting ROSAT PSPC countrate of 0.05 cts/s in the energy band 0.1- 2.4 keV. The sources have a detection likelihood of at least 15 and contain at least 15 source photons. At a brightness limit of 0.1 cts/s (8547 sources) the catalogue represents a sky coverage of 92 percent.

For each source are provided the ROSAT name, the position in equatorial coordinates, the positional error, the source countrate and error, the background countrate, exposure time, hardness-ratios HR1 and HR2 and errors, extent and likelihood of extent, and likelihood of detection. For 94 percent of the sources, visual inspection confirmed the results of the standard processing with respect to existence and position; the remaining 6 percent were reanalyzed and appropriately flagged. Broadband images are available for a subset of the flagged sources.

Questions or comments about the content of this catalogue may be directed to survey@xray.mpe.mpg.de.


Catalog Bibcode

1999A&A...349..389V

Parameters

Name
Rosat All-Sky survey Catalog source name.

RA_B1950
Right Ascension 1950 coordinates

Dec_B1950
Declination 1950 coordinates

RA
The source RA (displayed at the current equinox year).

Dec
The source Dec (displayed at the current equinox year).

LII
The requested Galactic longitude.

BII
The requested Galactic latitude.

Positional_Error
The error on the position given in arcseconds. (This includes a 6-arcsecond systematic error.)

Screen_Flag
Screening Flags

New_Data_Flag
The new data flag is a 4-character string composite of 4 flags (RIV?), each indicating additional screening criteria.

    R: sorce counts and extracted radius Recalculated
    I: broad band Image available (Note images are not available at HEASARC)
    V:  variability flag (not yet filled)
    ?: dummy flag
  
Each character (flag) in the string can have the following values: 'T' for true, 'F' or '_' for false and '.' for 'not used'.

Count_Rate
Source count rate vignetting corrected.

Count_Rate_Error
The error on count rate vignetting corrected. If this field is set to zero, that means the error has not been determined.

Background_Count_Rate
The background count rate, vignetting corrected, in counts/sec/arcmin^2.

Exposure
The exposure time of field given in seconds.

Hardness_Ratio_1
The hardness ratio defined as HR1=(B-A)/(B+A), where A are the counts in the PHA range 11-41 and B are the counts in the PHA range 52-201.

Hardness_Ratio_1_Error
Hardness Ratio 1 Error

Hardness_Ratio_2
The hardness ratio defined as HR2=(D-C)/(D+C), where C are the counts in the PHA range 52-90 and D are the counts in the PHA range 91-201.

Hardness_Ratio_2_Error
Hardness Ratio 2 Error

Source_Extent
The amount is specified, by which the source image exceeds the point spread function. The value is given in arcsec.

Extent_Likelihood
The likelihood of source extent. If > 9999.9, set to 9999.

Detect_Likelihood
The likelihood of source detection algorithm. If > 9999.9, set to 9999.

Extraction_Radius
The source extraction radius in arcsec. If > 9999.9 (e.g. Vela SNR!), set to 9999.

Priority_Flags
The priority flag is a string composite of 6 characters, each indicating the following flags:

    M-broad
    L-broad
    M-hard
    L-hard
    M-soft
    L-soft
  
Sliding window detection history using either the background map (M) or the local backgroumnd (B) ) = no detection, 1 = detection

High_Detect_Range
PHA Range with Highest Detection Likelihood

Vignetting_Factor
The telescope vignetting correction (1=on-axis lower than 1 off-axis)

Date_Included
Date when source was included. format :yymmdd; 000000: removed

Date_Modified
Date when source properties were changed. format :yymmdd; 000000:not changed

SASS_Field_ID
Identification number of SASS field. An overview of the field structure is available at URL http://www.xray.mpe.mpg.de/rosat/survey/rass-bsc/sup/psplit.ps.gz

SASS_Source_Number
SASS source number (MASOL number) in SASS field.


Contact Person

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

Page Author: Browse Software Development Team
Last Modified: 25-Jun-2008