ftp.hs.uni-hamburg.de/pub/outgoing/rass-id

A452      1998A&AS..127..145Bade+ The Hamburg/RASS Catalogue of optical
CATS      identifications     (ftp.hs.uni-hamburg.de/pub/outgoing/rass-id 6/98)
	  Comment: RADECJ, opt.class for ~15000 cands for 4665 RASS sources
	  2 Files: 205x79+152021x86 = 1.06 Mb
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|        The Hamburg/RASS Catalogue of Optical Identifications       |
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N. Bade (1), D. Engels (1), W. Voges (2), V. Beckmann (1), Th. Boller (2),
L. Cordis (1), M. Dahlem (3), J. Englhauser (2), K. Molthagen (1),
P. Nass (1,2), J. Studt (1), D. Reimers (1)

(1) Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg
(2) MPI fuer Extraterrestrische Physik, D-85740 Garching
(3) ESTEC, Astrophysics Division, Postbus 299 ,NL-2200 AG Noordwijk

Version 2.0, issued January 5, 1998   now 4665 positions, 

Version 1.1, issued December 5, 1996  additional entries in the X-ray rows
                                      (flags and date of last change)
Version 1.0, issued November 1, 1996
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GENERAL DESCRIPTION
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The file rass2id.cat provides information on optical identifications
to X-ray positions of the ROSAT All-Sky Survey (RASS). The file was created 
by correlating the Bright Source Catalogue of ROSAT (Voges et al., 1996) and 
the Hamburg/RASS Catalogue of Optical Identifications (HRC) (Bade et al., 
1996, in prep.). In the current state (Version 2.0) the catalogue
contains 4665 positions in the extragalactic northern sky. For each
X-ray position optical information taken from HQS objective prism and
direct Schmidt plates (Hagen et al., 1995, A&AS 111, 195) is given and
a finding chart derived from digitized direct plates as gzipped 
Postscript file is provided. If possible, the most likely optical
counterpart is marked in the catalogue and on the finding chart. 
For many of the newly processed HQS fields of Version 2.0 no direct
Schmidt plates from the HQS exists. In these cases we put finding
charts generated from the STScI Digitized Sky Survey on the ftp
server. We remind the reader that the STScI Digitized Sky Survey and
HQS prism plates have different epochs. This has to be taken into
account for stellar identifications. Furthermore the spectral
sensitivity of the  STScI Digitized Sky Survey and the HQS prism
plates is different.

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CONTENTS
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X-RAY ROWS
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The rows containing the X-ray information can  be recognized by 'RX' in the 
second and third column. They have the following structure:


Bytes    Format  Units                Explanations    

 1-16    A16                          Object name
19-20    I2                           R.A.: hours (2000.0)
22-23    I2                           R.A.: minutes (2000.0)
25-28    F4.1			      R.A.: seconds (2000.0)
31-33    I3                           Decl.: degree (2000.0)
35-36    I2                           Decl.: minutes (2000.0)
38-39    I2                           Decl.: seconds (2000.0)
43-45    I3      arcseconds           error radius derived from the BSC
51-56    I6                           internal number
62-64    I3                           identification code
69       I1                           flag, if set to 1, identification changed
                                      since last catalogue version
70       I1                           flag, if set to 1, entries to this X-ray
                                      position have changed since last 
                                      catalogue version, 
71       I1                           flag, supplementary X-ray positions are
                                      flagged with 1
74-79    A6                           date of last change

The identification code is defined as follows:
The first (and third) digit give(s) the classification:
1        AGN
2        Galaxy, derived from the morphology on the direct plates
3        Cluster
5        M dwarf
6        White Dwarf
7_1      K Dwarf
7_2      F or G star
7_3      Cataclysmic Variable (CV)
7_4      Bright Star (B < 13)
8        no plausible candidate found
803      one object in favourable position, but no spectral information
0        empty field on objective prism and direct plate within a radius
         of at least 40 arcsec

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


FINDING CHARTS
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The finding chart for each X-ray position is stored as
a gzipped Postscript file and they can be found in the 
directories d-10 to d+80. These directories arrange the
files into declination belts. Names of finding charts 
generated by the STScI Digitized Sky Survey begin with a 
'p'. 



OPTICAL ROWS
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Below the X-ray information rows with optical data
about objects in the error circle follow.
These lines have the following structure:


Bytes    Format  Units                Explanations    

14-16    I3                           Number, a '+' in front of the
                                      number marks the proposed
                                      optical counterpart
19-20    I2                           R.A.: hours (2000.0)
22-23    I2                           R.A.: minutes (2000.0)
25-28    F4.1			      R.A.: seconds (2000.0)
31-33    I3                           Decl.: degree (2000.0)
35-36    I2                           Decl.: minutes (2000.0)
38-39    I2                           Decl.: seconds (2000.0)
42-45    I4      arcseconds           X-ray position - optical position     
                                      in right ascension
48-51    I4      arcseconds           X-ray position - optical position
                                      in declination
55-57    I3      arcseconds           distance between X-ray and
                                      optical position
62-65    F4.1                         Optical magnitude B
                                      a '<' on column 61 means upper limit
                                      for magnitude, the object is saturated
                                      '>19.0' in column 61-65 means, that the
                                      optical counterpart is only visible
                                      on the direct plate not on the prism 
                                      plate(s)
                                      no entry means no B magnitude available
77-84    A8                           Classification for objective
                                      prism spectrum 


For the classification of objective prism spectra the following scheme
was adopted:

SUBDWARF        Hot Subdwarfs (sdO,sdB)
W-DWARF         White Dwarfs
STAR-BA         Balmer absorption lines, point-like image
STAR-FG         G-Band, Ca H+K, point-like image
STAR-K          G-Band, Ca H+K, redder continuum, point-like image
STAR-M          Very red, TiO lines, Ca I 4226, point-like image
CV              Cataclysmic variable, Balmer emission lines
GALAXY          Extended image on direct plate, no emission lines, 
                red continuum
AGN             Emission line(s), blue continuum, weak extension on
                direct plate allowed
BLUE GAL        moderately blue continuum, extended image on direct plate
QSO             Emission line(s), extremely blue continuum, 
                no extension on direct plate
EBL-WK          Extremely blue continuum, weak point-like object
BLUE-WK         Moderately blue continuum, weak point-like object
RED-WK          Red continuum, weak point-like object
UNIDENT         Classification open
OVERLAP         Classification not possible due to overlapping spectra
SATURATE        Classification not possible due to amplifier saturation

The catalogue can be used for scientific purposes if the above mentioned
paper is referenced.
For more detailed information about the identification code and the 
classification scheme for objective prism spectra the catalogue user is
also referred to this paper.

Acknowledgements:

The ROSAT project is supported by the Ministerium fuer Bildung, 
Wissenschaft, Forschung und Technologie (BMBF/DARA) and by the 
Max-Planck-Gesellschaft (MPG).

This research has 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.                                                            

This work 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.

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-rw-r--r--   1 3014     750         10215 Aug 31  1999 README
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drwxr-xr-x   2 3014     750         14336 Aug 31  1999 d+10
drwxr-xr-x   2 3014     750         23552 Aug 31  1999 d+20
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drwxr-xr-x   2 3014     750         18432 Aug 31  1999 d+40
drwxr-xr-x   2 3014     750         14336 Aug 31  1999 d+50
drwxr-xr-x   2 3014     750          8192 Aug 31  1999 d+60
drwxr-xr-x   2 3014     750          5120 Aug 31  1999 d+70
drwxr-xr-x   2 3014     750          1024 Aug 31  1999 d+80
drwxr-xr-x   2 3014     750          1024 Aug 31  1999 d-10
-rw-r--r--   1 3014     750        997316 Aug 31  1999 rass2idv1_1.cat
-rw-r--r--   1 3014     750         64103 Aug 31  1999 rass2idv1_1_sky.ps.gz
-rw-r--r--   1 3014     750       1242801 Aug 31  1999 rass2idv2_0.cat