IX/29               ROSAT All-Sky Survey Faint Source Catalog  (Voges+ 2000)
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ROSAT All-Sky Survey Faint source Catalogue (RASS-FSC)
      Voges W., Aschenbach B., Boller Th., Brauninger H., Briel U., Burkert W.,
      Dennerl K., Englhauser J., Gruber R., Haberl F., Hartner G., Hasinger G.,
      Pfeffermann E., Pietsch W., Predehl P., Schmitt J., Trumper J.,
      Zimmermann U.
    
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ADC_Keywords: X-ray sources ; Surveys
Mission_Name: ROSAT

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. ). 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 survey@xray.mpe.mpg.de.

File Summary:
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 FileName      Lrecl  Records   Explanations
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ReadMe            80        .   This file
rass_fsc.dat     212   105924   The ROSAT All Sky Survey Faint Source Catalog
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See also:
    IX/10A : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
    http://wave.xray.mpe.mpg.de/rosat/catalogues/rass-fsc : The ROSAT
           All-Sky Survey Faint Source Catalogue Home Page

Byte-by-byte Description of file: rass_fsc.dat
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   Bytes Format Units   Label     Explanations
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   1- 21  A21   ---     1RXS      ROSAT All-Sky Survey Catalogue source name (1)
  24- 32  F9.5  deg     RAdeg     Right ascension (J2000), decimal degrees
  34- 42  F9.5  deg     DEdeg     Declination (J2000), decimal degrees
  44- 46  I3    arcsec  PosErr    ?=0 Total positional error
                                   (including 6" systematic error)
  48- 52  A5    ---     ScrFlags  [T.F] screening flags (2)
  54- 57  A4    ---     NewFlag   [T._] 'new data' flags (3)
  60- 68  E9.3  ct/s    Count     ?=0 Source countrate (4)
  70- 78  E9.3  ct/s  e_Count     ?=0 Error on Count (4)
  80- 88  E9.3 ct/s/arcmin2 bgCt  ?=0 Background countrate (4)
  90- 95  I6    s       ExpTime   ?=0 Exposure time
  97-101  F5.2  ---     HR1       [-1/1]? Hardness ratio 1 (5)
 103-106  F4.2  ---   e_HR1       ? Error on HR1 (6)
 108-112  F5.2  ---     HR2       [-1/1]? hardness ratio 2 (5)
 114-117  F4.2  ---   e_HR2       ? Error on HR2 (6)
 119-123  I5    arcsec  Extent    Source extent, by which the source image
                                    exceeds the point spread function.
 125-128  I4    ---   L_Extent    ?=0 Likelihood of source extent (7)
 130-133  I4    ---     Ldetect   ?=0 Likelihood of
                                        source detection algorithm (7)
 135-139  I5    arcsec  ExtRad    ?=0 Extraction radius
 141-146  A6    ---     PrioFlags [01] priority  flags (8)
     147  A1    ---     PHA       [ABCDb] PHA range of best detection (9)
 149-152  F4.2  ---     VigFactor ?=0 Vignetting factor
 154-159  I6   "yyMMDD" IncDate   [000518]?=0 Date when source was included (10)
 161-166  I6   "yyMMDD" UpdDate   [000000]?=0 Date when source properties 
                                     changed (11)
 168-170  I3    ---     Ncand     Number of identification candidates in the
                                   correlation catalogue
 173-180  I8    ---     SASS      Identification number of SASS field (12)
     181  A1    ---     ---       [_]
 182-185  I4    ---     MASOL     SASS source number (MASOL number)
                                  in SASS field (mainly for internal use)
 187-189  I3    ---     src       Source number
 191-192  I2    yr      ObsBeg.Y  Beginning of observation (year, offset 1900)
 193-194  I2    "month" ObsBeg.M  Beginning of observation (month)
 195-199  F5.2  d       ObsBeg.D  Beginning of observation (day)
 201-202  I2    yr      ObsEnd.Y  Beginning of observation (year, offset 1900)
 203-204  I2    "month" ObsEnd.M  Beginning of observation (month)
 205-209  F5.2  d       ObsEnd.D  Beginning of observation (day)
 211-212  I2    ---     Rel       [0,99] Reliability of Source
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Note (1): The name includes the '1RXS' acronym, and is based
     on J2000 position (format JHHMMSS.S+DDMMSS).
     This name is used in the generation of a link to a broad band
     image if this image is available (see NewFlag, and Note (3))

Note (2): the flags are 'T' for 'true', 'F' or '_' for 'false'; '.' for not used
     n (byte 48) nearby sources affecting SASS flux determination
     p (byte 49) possible problem with position determination
     e (byte 50) source extended beyond SASS extraction radius
     d (byte 51) complex diffuse emission pattern
     m (byte 52) source missed by SASS

Note (3): the flags are 'T' for 'true', 'F' or '_' for 'false'; '.' for not used
     r (byte 54) source counts and extraction radius recalculated
     i (byte 55) broad band image available (html link!)
     v (byte 56) variability flag (not yet filled)
     . (byte 57) dummy flag

Note (4): Countrates are vignetting corrected

Note (5): The hardness ratios are defined by:
     hr1 = ( B - A ) / ( B + A )  , where
             A = countrate in PHA range  11 -  41 (~ 0.1-0.4 keV)
             B = countrate in PHA range  52 - 201 (~ 0.5-2.0 keV)
     hr2 = ( D - C ) / ( D + C )  , where
             C = countrate in PHA range  52 -  90 (~ 0.5-0.9 keV)
             D = countrate in PHA range  91 - 201 (~ 0.9-2.0 keV)
     (PHA = Pulse Height Amplitude)

Note (6): the true mean error is probably bigger, and
     values larger than 9.99 are set to 9.99

Note (7): values larger than 9999 are set to 9999

Note (8): the flags indicate the sliding window detection history
     using either the background map (M) or the local background (B),
     and take the values 0 = no detection, 1 = detection;
     The order of flags is:
     M-broad, L-broad, M-hard, L-hard, M-soft, L-soft

Note (9): the PHA (Pulse Height Amplitude) range
     PHA range with highest detection likelihood is indicated by
         A =  PHA range 11-41  (~ 0.1-0.4 keV)
         B =  PHA range 52-201 (~ 0.5-2.0 keV)
         C =  PHA range 52-90  (~ 0.5-0.9 keV)
         D =  PHA range 91-201 (~ 0.9-2.0 keV)
         b or blank means 'broad'

Note (10): a value "000000" for the date indicates a removed source.
     The "yy" part is for XXIst century

Note (11): a value "000000" indicates not-applicable date
     The "yy" part is for XXIst century

Note (12): An overview of the field structure is available at URL
     
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(End)                           Francois Ochsenbein [CDS]    26-May-2000