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2004.............Fresch
            The MASTER Optical Catalogue of Quasars, Quasar Candidates,   
                          and Other Radio/X-ray Objects 

              Eric Flesch, Wellington, New Zealand   14 January 2004

================================================================================

  The MASTER Catalogue aligns and overlays the year 2001/2 releases of the ROSAT
  HRI, RASS, PSPC and WGA X-ray catalogues, the NVSS (2002), FIRST (2003) and 
  SUMSS (2003) radio catalogues, the Veron QSO catalogue (2003) and various 
  galaxy/star reference catalogues onto the optical APM and USNO-A catalogues.
  This catalogue displays calculated percentage probabilities for each optical
  radio/X-ray-associated object of its likelihood of being a quasar, galaxy,
  star, or erroneous radio/X-ray association. 

  The main Master catalogue (Master.zip) displays all 501,761 radio/X-ray 
  associated optical objects and known quasars which are optically detected in
  APM/USNO-A.  Up to six radio/X-ray catalog identifications are presented for
  each optical object, plus any double radio lobes (21,498 of these).  These are 
  superimposed (and laterally fitted) onto a 670,925,779-object optical 
  background which combines APM and USNO-A data. 
  
  Objects presented in this catalogue are those optical APM/USNO-A objects which
  are associated with X-ray/radio detections, or any optically-found catalogued
  QSO/AGN/Bl Lac objects, with confidence >40% of being a radio/X-ray emitting
  optical object.  There are 501,761 objects included in all (inluding
  48,285 catalogued quasars), representing the 99.4% coverage of the sky 
  available from the APM and USNO-A. 

  Each object is shown as one line bearing the position in equatorial 
  coordinates, red and blue optical magnitudes (recalibrated -- see the HGU
  readme for details) and PSF class, calculated probabilities of the object 
  being, separately, a quasar, galaxy, star, or erroneous radio/X-ray 
  association, any radio identification from each of the NVSS, FIRST and SUMSS
  surveys, including candidate double-lobe detections, any X-ray identification
  from each of the Rosat HRI, RASS, PSPC and WGA surveys, including fluxes and
  field shifts of those identifications, plus, if already catalogued, the object
  name and redshift where applicable. 

  Questions or comments may be directed to eric@flesch.org.

File Summary:
--------------------------------------------------------------------------------
FileName               Lrecl  Records   Explanations
--------------------------------------------------------------------------------
Master-ReadMe.txt         80        .   This file
Master.txt               475   501761   The Master catalogue, with comprehensive
                                        listings of detections from 7 surveys.
                                        Also lists 2 radio lobes if applicable.
--------------------------------------------------------------------------------

See also: 
   APM home page              www.ast.cam.ac.uk/~apmcat
   USNO home page             www.nofs.navy.mil
   NVSS home page             www.cv.nrao.edu/nvss
   FIRST home page            sundog.stsci.edu
   HRI & PSPC home page       wave.xray.mpe.mpg.de/rosat/rra
   WGA home page              wgacat.gsfc.nasa.gov/wgacat/wgacat.html
   RASS-FSC home page         www.xray.mpe.mpg.de/rosat/survey/rass-fsc
   RASS-BSC home page         www.xray.mpe.mpg.de/rosat/survey/rass-bsc
   SUMSS home page            www.astrop.physics.usyd.edu.au/SUMSS/index.html
   Veron home page        www.obs-hp.fr/www/catalogues/veron2_11/veron2_11.html
   Principal Galaxy Catalogue (LEDA) home page   leda.univ-lyon1.fr
   Sloan Digital Sky Survey   www.sdss.org
   2dF QSO Redshift Survey    www.2dfquasar.org
   2dF Galaxy Redshift Survey www.mso.anu.edu.au/2dFGRS
   NED                        nedwww.ipac.caltech.edu
   CfA Redshift Catalogue     cfa-www.harvard.edu/~huchra/
   IRAS PSCz Redshift Survey  www-astro.physics.ox.ac.uk/~wjs/pscz.html


Byte-by-byte Description of the MASTER CATALOGUE: 
--------------------------------------------------------------------------------
   Bytes Format Units   Label     Explanations
--------------------------------------------------------------------------------
   1-  2  I2    h       RAh       Right Ascension J2000 (hours)  (1)
   3-  4  I2    min     RAm       Right Ascension J2000 (minutes)
   5-  8  F4.1  s       RAs       Right Ascension J2000 (seconds)
       9  A1    ---     DE-       Declination J2000 (sign)
  10- 11  I2    deg     DEd       Declination J2000 (degrees)  (1)
  12- 13  I2    arcmin  DEm       Declination J2000 (minutes)
  14- 15  I2    arcsec  DEs       Declination J2000 (seconds)
  17- 19  A3    ---     Descrip   Nature of object and any association (2)
  21- 24  F4.1  mag     Rmag      Red optical magnitude (3)
  26- 29  F4.1  mag     Bmag      Blue optical magnitude (3)
  31- 33  A3    ---     comment   Comment on optical object (4)
      34  A1    ---     R         Red optical PSF class (5)
      36  A1    ---     B         Blue optical PSF class (5)
  38- 58  A21   ---     Name      ID from the literature, where existing.
  59- 61  I3    pct     QSOpct    Confidence that the radio/X-ray association
                                  shows this object to be a quasar (6)
  62- 64  I3    pct     galpct    Confidence (as above) that obj is galaxy (6)
  65- 67  I3    pct     starpct   Confidence (as above) that obj is a star (6)
  68- 70  I3    pct     errpct    Probability that this is a false association,
                                  i.e., coincidental radio/X-ray & optical (7)
  71- 76  F6.3  z       z         Redshift from the literature. 
  78- 98  A21   ---     HRIID     ID from the ROSAT HRI survey.
  99-103  I5    cts/hr  hrate     Count rate of the HRI source (9)
 105-106  I2    arcsec  hdist     Distance from HRI detection to optical object
 108-110  I3    deg     htheta    Angle (N thru E) from optical obj to detection
 111-113  I3    pct     hconf     Confidence that this is a true association (7)
 115-130  A16   ---     hfield    HRI field ID of this detection.
 131-133  I3    arcsec  hrmove    R.A. arcsecs of the HRI field shift (10)
 134-136  I3    arcsec  hdmove    Decl arcsecs of the HRI field shift (10)              
 138-158  A21   ---     RASSID    ID from the ROSAT RASS survey.
 159-163  I5    cts/hr  rrate     Count rate of the RASS source (9)
 165-166  I2    arcsec  rdist     Distance from RASS detection to optical object
 168-170  I3    deg     rtheta    Angle (N thru E) from optical obj to detection
 171-173  I3    pct     rconf     Confidence that this is a true association (7)
 175-190  A16   ---     rfield    RASS field ID of this detection.
 191-193  I3    arcsec  rrmove    R.A. arcsecs of the RASS field shift (10)
 194-196  I3    arcsec  rdmove    Decl arcsecs of the RASS field shift (10)              
 198-218  A21   ---     PSPCID    ID from the ROSAT PSPC survey.
 219-223  I5    cts/hr  prate     Count rate of the PSPC source (9)
 225-226  I2    arcsec  pdist     Distance from PSPC detection to optical object
 228-230  I3    deg     ptheta    Angle (N thru E) from optical obj to detection
 231-233  I3    pct     pconf     Confidence that this is a true association (7)
 235-250  A16   ---     pfield    PSPC field ID of this detection.
 251-253  I3    arcsec  prmove    R.A. arcsecs of the PSPC field shift (10)
 254-256  I3    arcsec  pdmove    Decl arcsecs of the PSPC field shift (10)              
 258-278  A21   ---     WGAID     ID from the WGA (PSPC data) catalogue. 
 279-283  I5    cts/hr  wrate     Count rate of the WGA source (9)
 285-286  I2    arcsec  wdist     Distance from WGA detection to optical object
 288-290  I3    deg     wtheta    Angle (N thru E) from optical obj to detection
 291-293  I3    pct     wconf     Confidence that this is a true association (7)
 295-310  A16   ---     wfield    WGA field ID of this detection.
 311-313  I3    arcsec  wrmove    R.A. arcsecs of the WGA field shift (10)
 314-316  I3    arcsec  wdmove    Decl arcsecs of the WGA field shift (10)              
 318-338  A21   ---     FSID      ID from the FIRST or SUMSS radio catalogue. 
 339-343  I5    mJy     fsrate    Flux of the FIRST or SUMSS source (9)
 345-346  I2    arcsec  fsdist    Distance from FIRST/SUMSS detection to optical
 348-350  I3    deg     fstheta   Angle (N thru E) from optical obj to detection
 351-353  I3    pct     fsconf    Confidence that this is a true association (7)
 355-375  A21   ---     NVSSID    ID from the NVSS radio catalogue. 
 376-380  I5    mJy     nrate     Flux of the NVSS source (9)
 382-383  I2    arcsec  ndist     Distance from NVSS detection to optical object
 385-387  I3    deg     ntheta    Angle (N thru E) from optical obj to detection
 388-390  I3    pct     nconf     Confidence that this is a true association (7)
 392-412  A21   ---     Lobe1ID   FIRST/NVSS ID of a radio lobe for this object
 413-417  I5    mJy     lrate1    Flux of this lobe source (9)
 419-420  I2    arcsec  ldist1    Distance from lobe detection to central object
 422-424  I3    deg     ltheta1   Angle (N thru E) from central obj to this lobe
 425-427  I3    pct     lconf1    Confidence that this is a true association (7)
 429-449  A21   ---     Lobe2ID   FIRST/NVSS ID of radio lobe #2 for this object
 450-454  I5    mJy     lrate2    Flux of this lobe source (9)
 456-458  I2    arcsec  ldist2    Distance from lobe detection to central object
 459-461  I3    deg     ltheta2   Angle (N thru E) from central obj to this lobe
 462-464  I3    pct     lconf2    Confidence that this is a true association (7)
 466-467  A2    ---     cat       Source catalogue of name identification (11)
 469-470  A2    ---     zcat      Source catalogue of redshift value (11)
 472-474  I3    K       denscat   Sky density bin of this sky location (x1000)  

--------------------------------------------------------------------------------

Note (1): The location is given as per the IAU recommended naming convention,
     thus the location doubles as the name for each object.  When referring to
     a candidate from this quasars.org catalog, specify it as e.g., 
     QORG J000108.1-373858.

Note (2): Summarizes the identification (from the literature) and radio/X-ray 
     associations presented for this optical object.  Legend: 
     Q=QSO, G=galaxy, A=AGN, B=Bl Lac, S=star, U=unknown with redshift, 
     R=radio source, 2=Double-lobed radio source, X=X-ray source 
 
Note (3): Magnitudes have been recalibrated from the original APM / USNO-A
     values.  Estimated accuracy of these values is 0.2 from true, B-R to 0.1.
     However, USNO-A non-POSSI objects fainter than 18.5 can have larger errors.
     Extended objects brighter than mag 13 can be represented as far too bright.
     If image is absent in this color, the plate depth is shown in parentheses.        

Note (4): Legend:
     p = optical magnitudes are POSS-I E and O.  
    (no p)= Not POSS-I, so the magnitudes are UKST R and Bj.  
     v = variability over 1 magnitude detected across epochs for both red & blue
     m = proper motion detected across epochs (nominally over 3 arcseconds). 
     ? = inferred object, position and optical magnitudes are estimated in one 
         or both colours where the PSF is listed as "n".
         
Note (5): The APM provides PSF class, the USNO-A does not.  Legend:
     - = stellar PSF (from APM)
     1 = fuzzy PSF (from APM)
     2 = extended PSF.  Can be galaxies, merged stars, etc.
     n = no PSF available, usually USNO-A sourced.
     x = no image resolved (image fainter than plate depth, or confused, etc.)

Note (6): Probability that object is a QSO / galaxy / star is evaluated from the 
     radio/X-ray association with catalogued QSOs / galaxies / stars.  There are
     four cross-categories, these being the PSF (stellar appearance) of the 
     optical object, its B-R color, the offset of the optical and radio/X-ray 
     positions, and the ratio of the radio/X-ray flux to the optical flux (via
     magnitude), and the radio detections are pooled separately from the X-ray
     detections.  Candidates are compared by these qualities to known objects, 
     and the I.D. probabilities are set by numerical prevalence of the known 
     objects.  These same probabilities are also listed for the known objects,
     so that you may judge for yourself the effectiveness of this method in 
     correctly determining the nature of the optical object.  Note that the 
     probability of incorrect association (of the optical object to the 
     radio/X-ray detection) is listed in the fourth percentile column, and that
     the four columns add to 100%.  Thus the probability of incorrect 
     association is already built into the listed probabilities that the object
     is a radio/X-ray QSO, galaxy, or star.

     In this catalogue, a quasar is taken as any broad emission-line object, so
     includes Seyfert-1 galaxies and many/most Bl Lacs.  However, known objects
     display object categories as defined in the Veron catalogue.

Note (7): Confidence of association is based on whole-sky density of optical 
     objects of the listed PSF and B-R colors.  Density of such objects at x 
     arcseconds from the radio detections is compared with whole-sky density, 
     same for X-ray.  Ten times the density yields a confidence of 90%, etc.  
     Whole-sky object densities are sub-categorized by galactic density 
     subclasses to minimize local-sky bias to within 20% in most cases. 

     Also, see note (6) above.

Note (9): If following a radio detection (i.e. from FIRST, NVSS or SUMSS), then 
     this figure is the peak flux in mJy.  If the first detection is an X-ray 
     detection, then this figure is the countrate in counts/hour.  Values are 
     from their respective source catalogues.  Values over 99999 are displayed
     as 99999.

Note (10): Radio and X-ray surveys are comprised of a set of single observations 
     each of which cover a defined swath (field) of sky, but with some 
     uncertainty as to the precise location.  The ground-based FIRST, NVSS and 
     SUMSS radio surveys have very little uncertainty, but the ROSAT-satellite-
     -based HRI, RASS, PSPC and WGA surveys typically have positional 
     uncertainty up to 10 arcseconds for the HRI and 5-25 arcseconds for the 
     others.  A "best fit" between the detections and the optical background is
     used to precisely fix the astrometry of each field. This catalogue achieves
     that by weighing the individual objects in the optical background (see #7 
     above) and using likelihood algorithms to determine the best candidates, 
     using the 670,000,000-object HGU optical catalogue as the control.  The 
     correctness of the technique is seen with any number of spot checks such as
     the HRI NGC3628 field US700009H.N1 which has been shifted RA +5.8 arcsec 
     (positive is eastwards) and decl -14 arcsec (negative is southwards) to 
     become well-aligned with 5 known quasars in the field. 

Note (11): Source catalogues for names and redshifts are:
     2G: 2dFGRS  the 2dF Galaxy Redshift Survey 
         Colless, M., et al. 2001, MNRAS 328, 1039
     2Q: 2dF QSO Redshift Survey (2QZ)  
         Croom S.M., et al. 2003, MNRAS, submitted 
     3C: 3CRR  the online 3CRR catalogue at http://www.3crr.dyndns.org 
         Laing R.A., Riley J.M., Longair M.S. 1983, MNRAS 204, 151
     6D: the 6dF Galaxy Redshift Survey Early Data Release   
         Wakamatsu et al. 2002, IAU Regional Assembly, ASP Conf. Proc., in press
     6Q: 6dF QSO Redshift Survey (6QZ), Croom S.M. et al. 2003, MNRAS, submitted 
     CF: the CfA Redshift Catalogue, Huchra J. P., et al. 1996, yCat 7193, 0
     CN: the Common Name Cross Index, Smith, W.B., 1996 unpublished, IV/22 
     CV: the Atlas of Cataclysmic Variables  
         Downes, R. A., et al. 2001, PASP 113, 764
     EN: ENEAR, the Redshift-Distance Survey of Nearby Early-Type Galaxies  
         Wegner, G., et al., astro-ph/0308357, submitted to AJ.
     GC: General Catalogue of Variable Stars (Vol 1) with Improved Coordinates  
         Samus, N.N., et al. 2002, Astronomy Letters, Vol. 28 No. 3, pp. 174-181
     HD: the Henry Draper Extension Charts 
         Nesterov V.V., et al. 1995, A&AS 110, 367
     LB: Large Bright Quasar Survey  
         Hewett P.C., Foltz C.B., Chaffee F.H. 1995, AJ 109, 1498
     LC: the Las Campanas Redshift Survey, Shectman et al. 1996, ApJ 470, 172
     NE: the NASA/IPAC Extragalactic Database (NED) 
     NL: the revised New Luyten Two-Tenths catalogue of high proper-motion stars
         Salim, S., Gould, A. 2003, ApJ 582, 1011
     PG: Principal Galaxy Catalogue, Lyon-Meudon Extragalactic Database (LEDA)
         Paturel, G., Bottinelli, L., Gouguenheim, L. 1995, ApL&C 30, 13
     PS: the IRAS PSCz Redshift Survey, Saunders, W., et al. 2000, MNRAS 317, 55
     SD: SDSS, the Sloan Digital Sky Survey (SDSS Data Release 1)
         Abazajian, K., et al. 2003, AJ, submitted; astro-ph/0305492 
     TY: Tycho, Hog et al. 2000, A&A 355, 27
     UG: the catalogue of Arcsecond Positions of UGC Galaxies 
         Cotton W.D., Condon J.J. 1999, ApJS 125, 409
     VE: Catalogue of Quasars and Active Nuclei, 11th edition,
         Véron-Cetty, M.-P., Véron, P. 2003, A&A (in.press)
     WD: Spectroscopically Identified White Dwarfs
         McCook G.P., Sion E.M. 1999, ApJS 121, 1
     YL: Yale, the Bright Star Catalogue, 5th Revised Ed. 
         Hoffleit E.D., Warren Jr. W.H., 1991bsc, book, V/50
     ZW: the Updated Zwicky Catalog, Falco E.E., et al 1999, PASP 111, 438

If using this catalogue in published research, please add a small acknowledgement.