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MILLIQUAS - Million Quasars Catalog, Version 3.9 (30 June 2014)

HEASARC
Archive

Overview

This table contains the Million Quasars (MILLIQUAS) Catalog, Version 3.9 (30 June 2014). It is a compendium of all type I QSOs, AGNe, and BL Lacs in the literature, up to 30 June 2014; completeness is full or nearly so. High-confidence (70+%) photometric SDSS and radio/X-ray associated objects are included, which bring the total number of objects to 1,262,723. Objects have been de-duplicated across catalogs, and the earliest name and best redshift are presented for each. Astrometry is fixed onto a combined APM/USNO-B/SDSS optical background, and is accurate to within 1-2 arcseconds in every case. Astrometric corrections from the author's paper (2013,PASA,30,4) are included, as well as others. Note that lensed images and close objects images within 1.5 arcseconds are represented as single objects.

This version has the following changes from the previous edition:

(1) Quasar data brought up to publications as at 30 June 2014.
(2) XMM-Newton Slew Survey source catalog release 1.6 added to X-ray data.
(3) 1SXPS X-ray detections were being dropped; fixed, now 21268 are included.
(4) The Veron-Cetty & Veron Quasar Catalog (VCV) 13th edition (2010,A&A,518,10)
    is now fully mapped into optical; corrections from this are incorporated.

The contents are relatively simple, each object is shown as one entry with the sky coordinates, its name, red and blue optical magnitudes, PSF class, redshift, and the source catalog for its name and redshift, plus a radio and/or X-ray identifier where applicable.

The author's current plans are to keep this updated as a "living" QSO catalog, with a view to publishing a half-million confirmed quasars catalogue in 2015.

Questions/comments/praise/complaints may be directed to Eric Flesch at eric@flesch.org. He requests that, if you use this catalog in published research, that you please add a small mention (acknowledgment).

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 research has also made use of data obtained from the Chandra Source Catalog, provided by the Chandra X-ray Center (CXC) as part of the Chandra Data Archive.

Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy. The SDSS-III web site is http://www.sdss3.org/.

Version Log:

     0.1  22Apr09
     0.3   6May09  Added a radio identifier and an X-ray identifier.
     0.5  11May09  Added 30816 objects from newly calculated associations to
                         XMM, Chandra and SUMSS detections, plus some tweaks.
                         Also added QSO probability % for non-confirmed QSOs.
     0.8  22Jun09  Added Chandra Source Catalog 1.0 (2009).
     1.0  03Aug09  Extensive de-duplication. XMM Slew Catalog data added.
     1.4  20Aug09  Misc fixes in the de-duplications.
     1.5  29Aug09  Used XMM Slew Catalog v1.3
     2.0  14Jun10  Used XMM Slew Catalog v1.4, XMM3, and XAssist4.
     2.1  17Aug10  Removed 8627 NELGs masquerading as AGNe.
     2.2   7Jan11  About 10,000 AGNe from the previous edition are now
                   presented as QSOs. 796 AGNe mistakenly expunged in 2.1
                   have been restored.
     2.3   5Mar11  SDSS DR-8 and BOSS targets have been included and the
                   threshold for inclusions of candidates has been raised
                   from 60% to 70%.
     2.4   5Jun11  Improved QSO-likelihood calculation for the BOSS targets,
                   so 17% of previously included BOSS targets drop out.
                   Newly included data from several sources (see above).
     2.5  20Jul11  Some de-duplication of quasars which were discovered prior
                   to 1990, 200 recent NED quasars added, some radio/X-ray
                   associations to USNO-B optical data added.
     2.6  10Sep11  The USNO-B catalog has been added and hard-deduplicated
                   against APM and SDSS data to make a background pool of
                   1.04 billion optical objects. Also, about 12 million
                   orphaned one-color APM objects have been removed. There
                   are consequently improvements in this catalog's optical
                   selections and astrometry without changing the net totals
                   much. XMM Slew 1.5 catalog added. Some further astrometric
                   fixes and de-duplications of early quasars.
     2.7   5Nov11  New quasar publications to 4 November 2011 were added,
                   and a few fixes on individual objects incorporated.
     2.8  29Jan12  Completed the fixes of non-astrometric relic data from the
                   Veron-Cetty & Veron 13th edition. About 150 other fixes.
                   Quasars compilation updated through 27 January 2012.
     2.9   2Apr12  Data brought up to publications as of 31 March 2012,
                   about 50 astrometric fixes done, and the new FIRST radio
                   catalog, 12Feb16 version, incorporated.
     2.10  6Aug12  Data brought up to publications as of 31 July 2012, including
                   the SDSS-DR9 release, XAssist XMM-Newton and Chandra X-ray
                   data updated to 30 June 2012; as this is a catalog for
                   type I (broad-line) objects, 1870 Seyfert-2s, 532 LINERs,
                   and 6 NELGs were removed, but Bl Lacs were retained as
                   unconstrained emission objects.
     3.0   9Sep12  Data brought up to publications as of 31 August 2012.
                   Redshifts are calculated for the XDQSO photometric quasar
                   candidates. Fixed issues with 30 DEEP2 object. Separated
                   out 15 SDSS-DR9 object that had been conflated with others.
                   QSO-AGN separator restored to that used through v2.9, thus
                   ~5000 QSOs were re-classified as AGNe. AGNe historic names
                   sourced from the Principal Galaxy Catalogue.
     3.1  22Oct12  Quasar data brought up to publications as of 20 Oct. 2012,
                   including the new DR9 Quasar catalog (Paris I., 2012,
                   arXiv:1210.5166).
     3.2  10Feb13  Quasar data brought up to publications as of 9 Feb. 2013.
                   MMT quasar positions fixed, and made a few small
                   miscellaneous fixes.
     3.3   7Apr13  Quasar data brought up to publications as at 6 April 2013.
                   Added 713 new quasars from Palanque-Delabrouille et al.
                   (2013, A&A, 551, A29). Included SWIRE data, consisting of
                   117 confirmed quasars and >20K photometric quasars from
                   Rowan-Robinson et al. (2013, MNRAS, 428, 1958).
                   Located 8 QSOs that were previously uncertainly located
                   and removed 1 that had no credible candidates. Removed 26
                   SDSS-DR9 quasars after inspection showed they were only
                   artifacts. Removed 144 questionable quasars from Iovino
                   et al. (1996, A&AS, 119, 265). Removed 8 blazars classified
                   as white dwarfs by the SDSS DR7 WD Cat (2013,ApJS,204,5).
                   Miscellaneous: 4 moves, 2 de-dups, and 4 deletions found
                   after extensive trawling.
     3.4  11Jul13  Quasar data brought up to publications as at 11 July 2013.
                   The author's paper (2013,PASA,30,4) marked 9 QSOs as
                   uncertainly located. Of those:
                   (a) Q 0112-27 is finally sited at J011517.2-271223,
                       courtesy Cyril Hazard.
                   (b) Q 0752+617 is moved to J075646.6+613639, r=16.9, b=17.4,
                      as a better fit with its co-published quasar (NOTNI 16,
                      r=16.7, b=17.2).
                   Added 92 new quasars from Cyril Hazard. Q 1409+732 was found
                   to be sited on a plate flaw, and is now moved one arcmin
                   due East to perfect optical fit at J141003.2+725939,
                   r=19.3, b>22. XAssist v4 XMM-Newton & Chandra X-ray data
                   updated to 30-June-2013.
     3.5  11Aug13  Quasar data brought up to publications as at 10 August 2013,
                   including SDSS-DR10. Note that the DR10 is an automated
                   catalog, so its object classifications are not as
                   trustworthy as manual classifications. Thus, earlier
                   manual classifications are retained over DR10
                   classifications. XMM-Newton X-ray data updated to 3XMM-DR4
                   version (24-July-2013). FIRST radio data updated to
                   13Jun05 version (05-June-2013).
     3.6  23Oct13  Quasar data brought up to publications as at 22 October
                   2013. Two additional columns of radio/X-ray detections
                   were added. This is so that any radio lobes will always be
                   fully displayed, and extra detections from other source
                   catalogs give a sense of fuller coverage. 158 additional
                   quasars were added from SDSS-DR10. These were flagged as
                   bad astrometry, but they are confirmed by the author's
                   optical background database. Photometric quasar candidates
                   from surveys other than NBCKDE and XDQSO, e.g., SWIRE,
                   have been dropped because much of their yield are type 2.
                   This includes Palanque-Delabrouille et al.
                   (2011,A&A,530,122), which has been well investigated
                   spectroscopically and its residue thus less likely to be
                   QSOs. X-ray detections from the Champ2 catalog, Kim M. et
                   al, 2007,ApJS,169,401 have been removed. It's a small
                   catalog which, unlike others, does not present its raw
                   astrometry needed for calculating optical solutions. The
                   Veron quasar catalog v13 (2010 A&A,518A,10) included some
                   objects denoted as non-quasars by their discovery papers,
                   and the following have been removed as a result:
                   (a) 484 emission-line galaxies (ELGs) of z<0.46 from
                       Schneider/Schmidt/Gunn 1994,AJ,107,1245, incorporated
                       as QSOs by VCV13;
                   (b) 55 ELGs of Schneider/Schmidt/Gunn 1999,AJ,117,40;
                   (c) 58 galaxies from 2dF-GRS (Colless M. et al.,
                       astro-ph/0306581); and
                   (d) 41 galaxies from La Franca F. et al.,
                       1999,A&AS,140,351.
                   A few positional fixes, de-duplications, and removals of
                   type-2s.
     3.7  26Nov13  Quasar data brought up to publications as at 26 November
                   2013, including the SDSS DR10Q release by Isabelle Paris
                   et al, 2013 arXiv:1311.4870. 318 SDSS "quasars" of
                   auto-redshift>4 which were not subsequently confirmed by
                   visual inspection are removed as bogus (communication Adam
                   Myers). The Veron quasar catalog v13 (2010 A&A,518A,10)
                   flagged some objects as questionable in their "spec"
                   field. These have unclear spectra or are described as
                   "possible" by their discovery papers. 178 of these are
                   removed, and 52 such Bl-Lacs with redshift>0.5 are
                   re-classed to AGNs. Some positional fixes and
                   de-duplications of individual objects.
     3.8  16Feb14  Quasar data brought up to publications as at 15 February
                   2014. NBCKDE and BOSS quasar likelihoods have been
                   calibrated against the DR10Q (Paris I. et al, 2013
                   arXiv:1311.4870) classifications. The Swift X-ray Point
                   Source catalog (Evans P.A. et al, 2014,ApJS,210,8) is added
                   to the background data, resulting in 12604 associations.
                   110 SDSS-DR10 automated survey objects are removed as
                   artefacts. De-duplication of radio/X-ray detections
                   improved.
     3.9  30Jun14  See list of changes above.

References

Flesch, E.
    The Million Quasars (MILLIQUAS) Catalog, Version 3.9 (30 June 2014)
    http://quasars.org/milliquas.htm
See also:
   APM Catalog              http://www.ast.cam.ac.uk/~mike/apmcat
   USNO-A/B Catalogs        http://www.nofs.navy.mil
   NVSS Catalog             http://www.cv.nrao.edu/nvss
   FIRST Catalog            http://sundog.stsci.edu
   SUMSS Catalog            http://www.physics.usyd.edu.au/sifa/Main/SUMSS
   MGPS Catalog             http://www.physics.usyd.edu.au/sifa/Main/MGPS2
   ROSAT Catalogs           http://www.mpe.mpg.de/xray/wave/rosat/catalogue
                            http://www.mpe.mpg.de/xray/wave/rosat/rra/
   1WGA Catalog             http://wgacat.gsfc.nasa.gov/wgacat/wgacat.html
   Chandra Source Catalog   http://cxc.cfa.harvard.edu/csc/
   XAssist Home Page        http://xassist.pha.jhu.edu/zope/xassist
   XMM-Newton Catalog       http://xmmssc-www.star.le.ac.uk
   XMM-Newton Slew Survey   http://www.star.le.ac.uk/~amr30/Slew

Provenance

This table was updated by the HEASARC in June 2014 based on a machine-readable catalog obtained from the author's MILLIQUAS website at http://quasars.org/milliquas.htm after he notified the HEASARC that a new version was available.

Inclusion of SDSS Photometric QSO Candidates into MILLIQUAS

The two major releases of SDSS photometric QSO candidates are the NBCKDE catalog (Richards G.T. et al, 2009,ApJS,180,67) taken over the DR6 footprint, and the XDQSO catalog (Bovy J. et al, 2011,ApJ,729,141) over the DR8 footprint, which provides targets for the SDSS BOSS survey plus a set of fainter objects. Shared objects are here reported as XDQSO because of its larger footprint, else XDQSO would have a different data profile in the DR6 footprint compared with the DR8 extension. Thus the NBCKDE data reported here is minus those shared objects -- a subset with a lower yield ratio than that of the full NBCKDE data. This MILLIQUAS catalog adds pQSO and redshift calculations to these:

(1) pQSO, the probability that the candidate is a true QSO.

NBCKDE compares QSO & star density profiles per object to obtain a nominal pQSO. XDQSO is annotated with a nominal pQSO which their paper cautions is just a comparative figure and not a genuine QSO likelihood (see esp. their figure 14). In this "Million Quasars" catalog, the requirement is to display genuine odds for each candidate that it is indeed a quasar. The recent manual DR10Q catalog (Paris I. et al, 2013 arXiv:1311.4870) provides ~100K spectral classifications for these candidates by which their nominal pQSO-pcts can be calibrated into true QSO-pcts via a simple mapping. Individual notes per catalog:

BOSS candidates: These are XDQSO flagged with good=0 (which means good). I find that BOSS pQSOs map to true QSO-pcts by (1) subtract 14, and (2) for pQSO>90, also add (pQSO-90), and (3) for pQSO>94, also add 0.5*(pQSO-94). This mapping yields the following alignment to DR10Q spectral classifications:

 QSO-pct    DR10Q    DR10Q    DR10Q
 bin by 5   #objs     QSOs    QSOpct
 --------   -----    -----     ----
    50        679      349     51.4
    55       1088      622     57.2
    60       1708     1002     58.7
    65       2850     1844     64.7
    70       5176     3611     69.8
    75       7033     5265     74.9
    80       5832     4662     79.9
    85       7208     6163     85.5
    90      10392     9383     90.3
    95      20646    19837     96.1
 98-99(max) 16830    16552     98.3

NBCKDE candidates: These are a lower-yield subset of NBCKDE, as outlined above. This truncated data is not as well-behaved as the BOSS data, but a simple mapping is to (1) subtract 25, and (2) for pQSO>92, also add 1.5*(pQSO-92), and (3) for pQSO>98, also add 2.5*(pQSO-98). This yields:

 QSO-pct    DR10Q    DR10Q    DR10Q
 bin by 5   #objs     QSOs    QSOpct
 --------   -----    -----     ----
    50        140       84     60.0
    55        357      204     57.1
    60        803      497     61.9
    65       5884     3739     63.5
    70       5415     3723     68.8
    75       4195     3123     74.4
    80       2003     1588     79.3
 83-84(max)   878      750     85.4

XDQ candidates: These are XDQSO flagged with good>0 (which means not good). SDSS-3 deemed these objects too faint (etc) to use as BOSS targets. Their photometry have larger errors, so less reliable. However, high-pQSO objects still have good yields although DR10Q has only ~150 spectral classifications for them. I find an adequate mapping is QSOpct = 15 + 0.75*pQSO, but the data lose their coherence below QSOpct=80 so I exclude objects below there. This yields:

 QSO-pct    DR10Q    DR10Q     DR10Q
 bin by 5   #objs     QSOs     QSOpct
 --------   -----    -----     ----
 80-82          8        5      62.5
    85         25       23      92.0
 88-90(max)    87       75      86.2

(2) photometric redshifts.

NBCKDE provides photometric "most likely" redshifts as the weighted average of a bounded range for each candidate. XDQSO has not published redshifts, so these have been calculated using a training set of 199751 quasars from SDSS-DR9, binning the 4 colors by 0.1z, then using rainflow analysis to cluster the redshift bins for each XDQSO candidate. The outcome is similar to NBCKDE redshifts, and a comparison of 34035 NBCKDE & Milliquas & SDSS-DR9 QSO redshifts are listed at http://quasars.org/docs/NBCKDE-MQ-redshifts.txt , which treats each photometric redshift as a "hit" if within 0.5z of the true spectral redshift.

There it is seen that the NBCKDE hit rate is 25093/34035 = 73.7%, and the Milliquas hit rate is 25599/34035 = 75.2%. No doubt the NBCKDE method is better than this simple algorithm, but the author had the advantage of the very large SDSS-DR9 training set. This good performance validates the inclusion of these redshifts.


Parameters

Name
The designation of the source as taken from the literature. A "BOSS" prefix indicates an XDQSO BOSS target (XDQSO good=0). An "XDQ" prefix is an XDQSO non-BOSS object (XDQSO good=1,2). The name is left blank if the object is only a radio/X-ray associated object. If needing a designation for it, use the ref_name parameter and the J2000.0 equatorial coordinates to make an IAU-style name: catalog QO=QORG, AX=ARXA, MQ=MQ. For example: a source at 00 00 01.6 -25 17 07 with ref_name of 'AX' would be 'ARXA J000001.6-251707'.

RA
The Right Ascension of the quasar candidate in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.1 seconds of time in the original table.

Dec
The Declination of the quasar candidate in the selected equinox. This was given in J2000.0 coordinates to a precision of 1 arcsecond in the original table.

LII
The Galactic Longitude of the quasar candidate.

BII
The Galactic Latitude of the quasar candidate.

Broad_Type
The classification of the object, where the following abbreviations are used:

       Q = QSO from the literature, broad-line unresolved. 309,540 of these.
       A = AGN, QSO-like but integrated disk outshines core. 21,682 of these.
       B = Bl Lac object, 1578 of these.
       q = photometric quasar candidates, SDSS-based, 836,798 of these.
       R = Radio association displayed.
       X = X-ray association displayed.
       2 = Double radio lobe declaration (by data-driven algorithm).
  

Rmag
The red optical magnitude of the object. The type and source of this magnitude is specified in the optical_flag parameter value. Optical data are from the APM (http://www.ast.cam.ac.uk/~mike/apmcat/), USNO-A & USNO-B (http://www.nofs.navy.mil/), and the SDSS (http://sdss3.org/). Magnitudes have been recalibrated from the original APM/USNO-A values (which are POSS-I or UKST identified in the description for the optical_flag parameter) as documented in QORG. Calibrated USNO-A magnitudes are often retained in preference to USNO-B. APM galaxies brighter than 17th magnitude are usually represented as far too bright due to PSF modelling. If the optical_flag parameter value contains r/b/g/i/v/u/z, then the magnitudes are from the object's source catalog, e.g., SDSS, 2QZ, etc. Note that many SDSS magnitudes are extinction-corrected ~0.3 mag brighter.

Bmag
The blue optical magnitude of the object. The type and source of this magnitude is specified in the optical_flag parameter value. Optical data are from the APM (http://www.ast.cam.ac.uk/~apmcat/), USNO-A & USNO-B (http://www.nofs.navy.mil/), and the SDSS (http://sdss3.org/). Magnitudes have been recalibrated from the original APM/USNO-A values (which are POSS-I or UKST identified in the description for the optical_flag parameter) as documented in QORG. Calibrated USNO-A magnitudes are often retained in preference to USNO-B. APM galaxies brighter than 17th magnitude can be represented as far too bright due to PSF modelling. If the optical_flag parameter value contains r/b/g/i/v/u/z, then the magnitudes are from the object's source catalog, e.g., SDSS, 2QZ, etc. Note that many SDSS magnitudes are extinction-corrected ~0.3 mag brighter.

Optical_Flag
This field contains coded information on the optical source properties, as follows:

       p = optical magnitudes are POSS-I O (violet 4100A) and E (red 6500A).
           These are preferred because O is well-offset from E, and these plates
           were always taken on the same night, thus the red-blue color is
           correct even for variable objects.
       j = blue magnitude is SERC J (Bj 4800A blue-green) from the POSS-II or
           UKST surveys.  Red-blue color can be suspect because the plates were
           taken in different epochs, i.e. years apart.
       g = blue magnitude is SDSS green 4900A.
       u = blue magnitude is SDSS ultraviolet 3850A.
       b = blue magnitude is Vega 4400A.
       i = red magnitude is infrared.
       v = red magnitude is visual, i.e., white.
       z = red magnitude is far-infrared z.
       (not i/v/z) = standard red color 6500A.
       + = variability nominally detected for both red & blue.
       m = proper motion nominally detected.
       ? = astrometry/photometry is estimated.
  

Red_PSF_Flag
A coded representation for the point spread function (PSF) of the optical source in the red. The APM, USNO-B, and SDSS provide PSF class, albeit using different criteria. The codes are as follows:

       - = point source / stellar PSF (APM notation: -1, here truncated)
       1 = fuzzy / galaxy shape       (APM notation: 1 and some 2)
       n = no PSF available, whether borderline or too faint to tell, etc.
       x = not seen in this color (fainter than plate depth, or confused, etc.)
  

Blue_PSF_Flag
A coded representation for the point spread function (PSF) of the optical source in the blue. The APM, USNO-B, and SDSS provide PSF class, albeit using different criteria. The codes are as follows:

       - = point source / stellar PSF (APM notation: -1, here truncated)
       1 = fuzzy / galaxy shape       (APM notation: 1 and some 2)
       n = no PSF available, whether borderline or too faint to tell, etc.
       x = not seen in this color (fainter than plate depth, or confused, etc.)
  

Redshift
The redshift of the object, taken from the literature as specified in the ref_redshift parameter. Photometric most-likely redshifts are rounded here to 0.1 z. The photometric redshifts provided by this catalog are discussed in the Section "Inclusion of SDSS Photometric QSO Candidates into MILLIQUAS" above.

Ref_Name
The literature reference (with counts of name and redshift in parentheses) from which the name was taken, using the following abbreviations:

       2d (91,6): 2dF GRS, Colless M. et al, 2001,MNRAS,328,1039
       2L (308,95): 2LAC, Ackermann M. et al, 2011,ApJ,743,171
       2Q (22744,19396): 2QZ, Croom S.M. et al, 2004,MNRAS,349,1397
       2S (7975,6933): 2SLAQ, Croom S.M. et al, 2009,MNRAS,392,19
       6d (24,58): 6dF Galaxy Survey, Jones D.H. et al, 2009,MNRAS,399,683
       6Q (263,262): 6QZ, same attribution as 2QZ
       AE (16,16): AEGIS, Yan R. et al, 2011,ApJ,728,38
       AL (1,1): ALHAMBRA, Matute I. et al, 2013,arXiv:1307.5117
       AT (68,69): ATLAS, Mao M. et al, 2012,MNRAS,426,3334
       AX (15077,0): Atlas of Radio/X-ray Associations, Flesch E.,2010,PASA,27,283
       BF (28,12): BFOSC bright QSOs, Wu X.-B. et al, 2012,arXiv:1207.0204
       Bu (4,4): Burbidge E.M., October 2003, Keck-I LRIS, unpublished.
       BZ (109,186): BZCAT v4.1.1, Massaro E. et al, 2012, www.asdc.asi.it/bzcat
       CB (2,2): Chandra binaries, Green P. et al, 2011,ApJ,743,81
       CF (9,9): CFHIZQ, Willott C. et al, 2010,AJ,139,906
       Ch (97,98): ChaMP AGN, Trichas M. & Green P. et al, 2012,ApJS,200,17
       CL (8,47): CLASS Bl Lacs, March M.J.M. & Caccianiga A.,2013,MNRAS,430,2464
       CO (23,22): COSMOS hi-z, Masters D. et al, 2012,ApJ,755,169
       CQ (23,16): Red QSOs, Fynbo J. et al, 2013,ApJS,204,6
       CR (18,18): CRTS Slepian, Graham M. et al, 2014,arXiv:1401.1785
       CW (6,0): Case low-dispersion survey, Pesch P. et al, 1985-1995 misc publ.
       DE (1435,1432): DEEP2 Redshifts DR4, http://deep.berkeley.edu/DR4/home.html
       DP (2,136): Double-Peaked NELGs, Ge J.-G. et al, 2012,ApJS,201,31
       EC (7,7): E-CDFS radio, Bonzini M. et al, 2012,ApJS,203,15
       F2 (20,20): FIRST-2MASS red quasars, Glikman E. et al, 2012,ApJ,757,51
       FE (21,21): Faint End of QLF, Glikman E. et al, 2010,ApJ,710,1498
       GA (1,1): Giant Arcs sextuple, Dahle H. et al, 2012,arXiv:1211.1091
       GR (7,23): Gamma-ray Bl Lacs, Shaw M.S. et al, 2013,ApJ 764,135
       GS (14,15): GOODS-SOUTH,Villforth/Sarajedini/Koekemoer,2012,MNRAS,426,360
       HA (7,0): Halton Arp, misc. publications
       HB (41,29): Hewitt A., Burbidge G., 1989,ApJS,69,1
       HC (8,8): HST-COS, Rao S. et al, 2013,MNRAS,432,866
       HR (56,56): High Redshift Stripe 82,McGreer I.D. et al,2012,ApJ,768,105
       HS (3,2): Herschel-SPIRE, Casey C.M. et al, 2012,ApJ,761,139
       HZ (92,86): Cyril Hazard, 2013, in preparation.
       I9 (7,8): Integral IX, Masetti N. et al, 2012,A&A,538,123
       IA (11,11): Integral X, Masetti N. et al, 2013,arXiv:1307.2898
       IB (11,11): INTEGRAL/IBIS AGN, Malizia A. et al, 2012,MNRAS,426,1750
       IC (33,35): ICRF South, Titov O. et al, 2011,AJ,142,165
       IZ (1,1): Polsterer K., Zinn P.-C. & Gieseke F., 2013,MNRAS,428,226
       KA (3,3): Kepler quasars, Mushotzky R. et al, 2011,ApJ,743,12
       KB (12,12): Kepler blue H excess, Scaringi S. et al, 2013,MNRAS,428,2207
       KE (5,2): KEYFIELD, Anderson M. & Filipovic M., 2009,SerAJ,179,7
       KH (14,14): Harris K.A., thesis, 2012,PhDT,15 (arXiv:1201.5746)
       KX (274,214): KX quasars, Maddox N. et al, 2012,MNRAS,424,2876
       L1 (8,8): LAMOST commissioning, Wu X.-B. et al, 2010,RAA,10,745
       L2 (520,518): LAMOST Andromeda pilot, Huo Z.-Y. et al, 2013,AJ,145,159
       LC (6,6): Lopez-Corredoira M. et al, 2008,A&A,480,61
       LM (142,136): LMC Magellanic, Kozlowski S. et al, 2012,ApJ,746,27
       LO (10,10): LOCUSS, Haines, C.P. et al, 2012,ApJ,754,97
       MA (61,62): MASIV, Pursimo T. et al, 2013,ApJ,767,14
       MB (709,696): MMT-BOSS, Palanque-Delabrouille N. et al, 2013,A&A,551,A29
       MG (543,574): Magellanic Quasars, Kozlowski S. et al, 2013,arXiv:1305.6927
       MM (174,173): MMT-BOSS pilot, Ross N.P. et al, 2012,ApJS,199,3
       MQ (56043,340294): MILLIQUAS, original data in this catalog. Flesch E.,2013
       NB (150378,484930): NBCKDE, Richards G.T. et al, 2009,ApJS,180,67
       NE (974,307): NASA/IPAC Extragalactic DB, http://ned.ipac.caltech.edu
       P2 (8,8): Pan-Starrs hi-z, Banados E. et al, 2014, arXiv:1405.3986
       PB (14,28): Palermo Swift/BAT, Parisi P. et al, 2013,arXiv:1311.1458
       PG (4023,4): Principal Galaxy Catalogue, Paturel G. et al, 2003,A&A,412,45
       PS (1,1): Pan-Starrs hi-z, Morganson E. et al, 2012,AJ,143,142
       QO (22003,0): QORG, Flesch E. and Hardcastle M., 2004,A&A,427,387
       QP (54,54): QPQ6, Prochaska J.X. et al, 2013, arXiv:1308.6222
       QQ (2,2): QQQ Triplet, Farina E.P. et al, 2013,MNRAS,431,1019
       S2 (120,124): Southern 2MASS AGN using 6dF, Masci F. et al,2010,PASA,27,302
       S3 (2888,4669): SDSS Data Release 1 to 3 AGN (combined files)
       S4 ( 785,1429): SDSS Data Release 4 increment AGN
       S5 ( 779,1444): SDSS Data Release 5 increment AGN
       S6 ( 979,1638): SDSS Data Release 6 increment AGN
       S7 (2030,3083): SDSS Data Release 7 increment (incl special & extra) AGN
       S8 (4999,2711): SDSS DR8, Aihara H. et al, 2011,ApJS,193,29
       S9 (79081,4455): SDSS DR9 AGN, Ahn C.P. et al, 2012, http://sdss3.org/dr9
       SA (71566,4905): SDSS DR10, 2013, http://sdss3.org/dr10
       SL (33,32): SDSS Lens Search, Inada N. et al, 2012,AJ,143,119
       SM (29,29): SMC Magellanic, Kozlowski S.,Kochanek,Udalski, 2011,ApJS,194,22
       SN (2897,88569): SDSS DR9Q manual, Paris I. et al, 2012,A&A,548,66
       SP (153,151): SDSS DR5Q manual, Schneider D. et al, 2007,AJ,134,102
       SQ (100023,97497): SDSS DR7Q manual, Schneider D. et al, 2010,AJ,139,2360
       SR (24,20): SDSS Radio, McGreer I., Helfand D., White R., 2009,AJ,138,1925
       ST (4043,71568): SDSS DR10Q visual, Paris I. et al, 2013,arXiv:1311.4870
       SV (91,97): Spitzer mid-IR survey, Lacy M. et al, 2013, arXiv:1308.4190
       SW (117,117): SWIRE, Rowan-Robinson M. et al, 2013,MNRAS,428,1958
       SX (13,14): Subaru-XMM Deep, Hiroi K. et al, 2012,ApJ,758,49
       UF (6,6): UKIDSS-FIRST, Glikman E. et al, 2013,arXiv:1309.6626
       UL (1,1): ULAS hi-z, Mortlock D. et al, 2011,Nature,474,616
       UR (6,6): UKIDSS red QSOs, Banerji M. et al., 2012,MNRAS,427,2275
       UV (2,2): UVEX survey, Verbeek K. et al, 2012,MNRAS,426,1235
       VE (19698,16862): Veron 13th ed, Veron-Cetty M. & Veron P., 2010,A&A,518,10
       VH (2,2): VISTA-WISE Hyperluminous, Banerji M. et al, 2013,MNRAS,429,55
       VK (3,3): VIKING hi-z, Venemans B.P. et al, 2013,arXiv:1311.3666
       VL (168,98): VLT-LBG, Crighton N. et al, 2011,MNRAS,414,28
       W2 (12,16): WISE-2MASS-RASS, Edelson R. & Malkan M., 2012,ApJ,751,52
       WA (1,1): MAMBO hi-z, Wang R. et al, 2008,ApJ,687,848
       WE (41,0): Weedman D., 1985,ApJS,57,523
       WI (3,3): WISE-selected, Stern D. et al, 2012,ApJ,753,30
       WR (5,5): Wolf-Rayet QSOs, Neugent K. & Massey P., 2011,ApJ,733,123
                        and Neugent K., Massey P., Georgy C., 2012,ApJ,759,11
       WS (5,5): Warren S. J., in preparation, 2014
       XB (131,132): XBSS, Caccianiga A. et al, 2008,A&A,477,735
       XC (105,121): XMM-COSMOS, http://www2011.mpe.mpg.de/XMMCosmos/xmm53_release
       XD (686394,0): SDSS-XDQSO, Bovy J. et al, 2011,ApJ,729,141
       XL (223,193): XMM-LSS sources, Stalin C.S. et al, 2010,MNRAS,401,294
       XM (157,159): XMSS, Barcons X. et al, 2007,A&A,476,1191
       XU (2,2): XMM Cluster survey, Hilton M. et al, 2010,ApJ,718,133
       XW (400,417): XWAS, Esquej P. et al, 2013,arXiv:1302.5329
       YF (6,4): YFOSC hi-z, Wu X.-B. et al, 2012,RAA,12,1185
       Zw (4,5): the Updated Zwicky Catalog, Falco E.E. et al, 1999,PASP,111,438
  

Ref_Redshift
The literature reference for the redshift (with counts of name and redshift in parentheses), using the same abbreviations as used for the ref_name parameter (q.v.).

QSO_Prob
For a QSO candidate (type=q, or starting with R/X/2), this field contains the nominal probability that this object is a QSO, in percent, based on photometric and/or radio/X-ray association analysis. For a known QSO (type=Q/A/B), this field contains the percent chance that the shown radio/X-ray detection(s) is truly associated to it.

929,923 objects without spectroscopic confirmation are included where of >=70% probability. Two families of calculated objects are included:

(1) Photometric quasars, mostly from the SDSS-based NBCKDE/XDQSO catalogs, totalling 836,798 of which ~38,000 also show radio/X-ray association. The displayed probability of NBCKDE/XDQSO objects is not from their catalogs which provide data ratios only; instead, the displayed absolute probability is calculated as described in the Section "Inclusion of SDSS Photometric QSO Candidates into MILLIQUAS" above.

(2) Radio/X-ray associated objects, totalling 93,125 without any other attribution. The displayed probability is calculated as described in the ARXA/QORG papers.

About 38,000 photometric quasars are also radio/X-ray associated, and the displayed probability figure combines the photometric QSO probability P1 and the radio/X-ray derived QSO probability P2 as

       P = 1/(1+((1-P1)*(1-P2))/(P1*P2)).
  
Using the probability, as expected, these 1,262,723 objects will yield 1,154,243 actual quasars, making MILLIQUAS a true million-quasar catalog.

Radio_Name
The identification of the radio source associated with the quasar candidate, if any.

Xray_Name
This is usually the identification of the X-ray source associated with the quasar candidate, if any, but it can also be the identification of a radio lobe, if the radio_name parameter for the object itself contains the name of a radio lobe.

Radio/X-ray detections come from the following catalogs (and their respective home pages):

       FIRST: VLA FIRST survey, 13Jun05 version, http://sundog.stsci.edu
       NVSS: NRAO VLA sky survey, http://www.cv.nrao.edu/nvss
       SUMSS: Sydney U. Molonglo, http://www.physics.usyd.edu.au/sifa/Main/SUMSS
       MGPS: Molonglo galactic plane survey, same attribution as SUMSS

       ROSAT catalogs home page: http://www.mpe.mpg.de/xray/wave/rosat/catalogue
       -- 1RXH: ROSAT HRI (high resolution imager)
       -- 1RXS: ROSAT RASS (all-sky survey, both bright & faint)
       -- 2RXP/2RXF: ROSAT PSPC (position sensitive proportional counter)
       1WGA: White, Giommi & Angelini, http://wgacat.gsfc.nasa.gov/wgacat/wgacat.html
       CXO: Chandra Source Catalog, http://cxc.cfa.harvard.edu/csc
       CXOX: XAssist Chandra source list, http://xassist.pha.jhu.edu/zope/xassist
       3XMM: XMM-Newton, http://xmm.esac.esa.int/xsa
       XMMSL: XMM-Newton Slew survey, http://www.star.le.ac.uk/~amr30/Slew
       XMMX: XAssist XMM-Newton source list, http://xassist.pha.jhu.edu/zope/xassist
       1SXPS: Swift X-ray Point Source catalog, http://www.swift.ac.uk/1SXPS

       Optical field solutions are calculated from the raw source positions of all
       these catalogs as described in the author's ARXA paper (2010,PASA,27,283).
  

Alt_Name_1
The identification of the radio lobe or an additional radio or X-ray identification associated with the quasar candidate, if any.

Alt_Name_2
An additional identification of the radio lobe or an extra X-ray identification associated with the quasar candidate, if any.

Class
The HEASARC Browse object classification, based on the information given in the broad_type parameter.


Contact Person

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

Page Author: Browse Software Development Team
Last Modified: 30-Jun-2014