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- Last Modified: 10-Apr-2013
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MILLIQUAS - Million Quasars Catalog, Version 3.3 (7 April 2013) |
HEASARC Archive |
This version has the following changes from the previous edition:
(1) Quasar data brought up to publications as at 6 April 2013.
(2) Individual quasar data from 2013,A&A,551,A29 "Quasar Luminosity Function
from dedicated SDSS-III and MMT data" by N. Palanque-Delabrouille et al,
have been kindly provided by the lead author. This adds 713 new quasars.
(3) SWIRE data is now included, consisting of 117 confirmed quasars and >20K
photometric quasars from Rowan-Robinson M. et al, 2013,MNRAS,428,1958.
(4) The author's paper 2013-PASA-30-4 marked 9 QSOs as uncertainly located.
Of those:
(a) The author has found Q 0112-27 at J011446.4-271408, via
1RXS J011446.4-271419.
(b) XSF3:29 is found at J034116.3-435748, via 2RXP J034116.6-435754.
(c) RXS J11167-1711 found at J111645.6-171155, via 1RXS J111644.6-171135.
(d) 1H 0828-706 is removed as there are no credible candidates.
(5) 26 SDSS-DR9 quasars removed as inspection shows they are only artifacts.
(6) Iovino et al, 1996 A&AS,119,265 presented 1581 quasar spectra of which 144
were marked by them as questionable ('?'). Those 144 are often anomalously
bright and none show radio/X-ray associations. Those 144 are now removed.
(7) Eight blazars without redshift have been dropped as those optical objects
have been classed as white dwarfs by the SDSS DR7 WD Cat, 2013,ApJS,204,5.
(8) Miscellaneous: 4 moves, 2 de-dups, and 4 deletions found after extensive
trawling. This catalog is looking very clean now.
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, and to think about formal publication at a later date.
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 See list of changes above.
Flesch, E.
The Million Quasars (MILLIQUAS) Catalog, Version 3.3 (7 April 2013)
http://quasars.org/milliquas.htm
See also:
APM home page http://www.ast.cam.ac.uk/~apmcat
USNO-A home page http://www.nofs.navy.mil
NVSS home page http://www.cv.nrao.edu/nvss
FIRST home page http://sundog.stsci.edu
SUMSS home page http://www.astrop.physics.usyd.edu.au/SUMSS/
XMM-Newton home page http://xmmssc-www.star.le.ac.uk
HRI & PSPC home page http://www.mpe.mpg.de/xray/wave/rosat/rra/
WGA home page http://wgacat.gsfc.nasa.gov/wgacat/wgacat.html
RASS-FSC home page http://www.xray.mpe.mpg.de/rosat/survey/rass-fsc
RASS-BSC home page http://www.xray.mpe.mpg.de/rosat/survey/rass-bsc
Chandra Source
Catalog home page http://cxc.cfa.harvard.edu/csc/
XAssist home page http://xassist.pha.jhu.edu/zope/xassist
(XMMX & CXOX sources are from XAssist)
(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 author (Eric Flesch) accordingly analyzed the photometric candidates using techniques similar to the QORG (Flesch & Hardcastle 2004,A&A,427,387) processing. This uses a 4-color binned training set "flooded" with 10,000,000 anonymized XDQSO stars to calculate pQSOs. These were then used to adjust the NBCKDE & XDQSO nominal pQSOs into the "genuine" pQSOs reported here.
The SDSS-DR9 presents 31,007 typed objects which were previously listed as BOSS photometric quasars in Milliquas v2.9. Comparing the QSO-pcts reported there with those DR9 BOSS results yields:
QSO-pct are total hit bin by 5 QSOs objs pct -------- ----- ----- ---- 70-72 2123 2427 87.5 75 3355 3801 88.3 80 5789 6311 91.7 85 5634 6089 92.5 90 5327 5721 93.1 95 4709 4968 94.8 98-100 1678 1690 99.3 ------- ----- ----- ---- total 28615 31007 92.3Thus, the QSO yield is higher than this catalog's QSO-pcts, and true pQSO is underreported by about half. It seems a 5M "flood" should have been used instead of 10M. However, the resultant over-performing QSO-pcts enables confident use of the candidates presented in this catalog.
(2) photometric redshifts.
NBCKDE provides photometric "most likely" redshifts as the weighted average of a bounded range for each candidate. SWIRE also provides photometric redshifts via a multi-wavelength algorithm. 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.
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. 234,554 of these.
A = AGN, QSO-like but disk resolved on survey plates. 21,391 of these.
B = Bl Lac object, 1763 of these.
q = photometric quasars, mostly from SDSS or SWIRE. 912,702 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/~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.
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 (62,79): 2dF GRS, Colless M. et al, 2001,MNRAS,328,1039
2L (309,96): 2LAC, Ackermann M. et al, 2011,ApJ,743,171
2M (120,124): Southern 2MASS AGN using 6dF, Masci F. et al,2010,PASA,27,302
2Q (22834,19482): 2QZ, Croom S.M. et al, 2004,MNRAS,349,1397
2S (7974,6931): 2SLAQ, Croom S.M. et al, 2009,MNRAS,392,19
6d (20,59): 6dF Galaxy Survey, Jones D.H. et al, 2009,MNRAS,399,683
6Q (265,264): 6QZ, same attribution as 2QZ
AE (16,16): AEGIS, Yan R. et al, 2011,ApJ,728,38
AT (68,69): ATLAS, Mao M. et al, 2012,MNRAS,426,3334
AX (15143,0): Atlas of Radio/X-ray Associations, Flesch E.,2010,PASA,27,283
BF (28,19): 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 (103,188): 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 (98,98): ChaMP AGN, Trichas M. & Green P. et al, 2012,ApJS,200,17
CL (7,47): CLASS Bl Lacs, March M.J.M. & Caccianiga A.,2013,arXiv:1301.6550
CO (23,22): COSMOS hi-z, Masters D. et al, 2012,ApJ,755,169
CQ (23,17): Red QSOs, Fynbo J. et al, 2013,ApJS,204,6
CW (7,0): Case low-dispersion survey, Pesch P. et al, 1985-1995 misc publ.
DE (1436,1432): DEEP2 Redshifts DR4, http://deep.berkeley.edu/DR4/home.html
DP (2,135): 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 (22,21): FIRST-2MASS red quasars, Glikman E. et al, 2012,ApJ,757,51
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 (42,30): Hewitt A., Burbidge G., 1989,ApJS,69,1
HC (8,8): HST-COS, Rao S. et al, 2013,arXiv:1302.7026
HR (56,56): High Redshift Stripe 82,McGreer I.D. et al,2012,arXiv:1212.4493
HS (3,3): Herschel-SPIRE, Casey C.M. et al, 2012,ApJ,761,139
IB (11,11): INTEGRAL/IBIS AGN, Malizia A. et al, 2012,MNRAS,426,1750
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 (273,234): KX quasars, Maddox N. et al, 2012,MNRAS,424,2876
LA (8,8): LAMOST, Wu X.-B. et al, 2010,RAA,10,745
LC (7,7): Lopez-Corredoira M. et al, 2008,A&A,480,61
LM (144,144): LMC Magellanic, Kozlowski S. et al, 2012,ApJ,746,27
LO (11,11): LOCUSS, Haines, C.P. et al, 2012,ApJ,754,97
MA (61,63): MASIV, Pursimo T. et al, 2013,arXiv:1302.3409
MB (713,718): MMT-BOSS, Palanque-Delabrouille N. et al, 2013,A&A,551,A29
MM (174,174): MMT-BOSS pilot, Ross N.P. et al, 2012,ApJS,199,3
MQ (37773,351059): MILLIQUAS, original data in this catalog. Flesch E.,2012
NB (525492,524841): NBCKDE, Richards G.T. et al, 2009,ApJS,180,67
NE (1051,375): NASA/IPAC Extragalactic DB, http://ned.ipac.caltech.edu
PD (394,0): Palanque-Delabrouille N. et al, 2011,A&A,530,122
PG (3980,5): 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 (22939,0): QORG, Flesch E. and Hardcastle M., 2004,A&A,427,387
QQ (2,2): QQQ Triplet, Farina E.P. et al, 2013,arXiv:1302.0849
S1 (2919,4725): SDSS Data Release 1 to 3 AGN (combined files)
S4 ( 788,1438): SDSS Data Release 4 increment AGN
S5 ( 786,1449): SDSS Data Release 5 increment AGN
S6 ( 983,1645): SDSS Data Release 6 increment AGN
S7 (2121,3141): SDSS Data Release 7 increment (incl special & extra) AGN
S8 (5185,3162): SDSS DR8, Aihara H. et al, 2011,ApJS,193,29
S9 (79877,5511): SDSS DR9 AGN, Ahn C.P. et al, http://sdss3.org/dr9
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 (2898,88698): SDSS Quasar DR9, Paris I. et al, 2012,A&A,548,66
SP (156,154): SDSS Quasar DR5, Schneider D. et al, 2007,AJ,134,102
SQ (100407,97915): SDSS Quasar DR7, Schneider D. et al, 2010,AJ,139,2360
SR (24,21): SDSS Radio, McGreer I., Helfand D., White R., 2009,AJ,138,1925
SW (24383,24391): SWIRE, Rowan-Robinson M. et al, 2013,MNRAS,428,1958
SX (13,14): Subaru-XMM Deep, Hiroi K. et al, 2012,ApJ,758,49
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 (20564,17719): 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
VL (168,99): VLT-LBG, Crighton N. et al, 2011,MNRAS,414,28
W2 (259,16): WISE-2MASS-RASS, Edelson R. & Malkan M., 2012,ApJ,751,52
WD (3,0): redshift, but claimed by SDSS DR7 White Dwarf cat,2013,ApJS,204,5
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
XB (131,133): XBSS, Caccianiga A. et al, 2008,A&A,477,735
XC (2,2): XMM Cluster survey, Hilton M. et al, 2010,ApJ,718,133
XD (362277,1): SDSS-XDQSO, Bovy J. et al, 2011,ApJ,729,141
XL (223,194): XMM-LSS sources, Stalin C.S. et al, 2010,MNRAS,401,294
XM (157,160): XMSS, Barcons X. et al, 2007,A&A,476,1191
YF (6,4): YFOSC hi-z, Wu X.-B. et al, 2012,RAA,12,1185
Zw (5,5): 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
The nominal probability that this object is a QSO, in percent,
based on either photometric or radio/X-ray association analysis. Note that
this object may be a catalogued QSO in which case this "nominal" figure is
superseded. 988,560 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 912,702 of which ~35,000 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. Photometric quasars from SWIRE, PD Stripe 82 and WISE-2MASS-RASS have been set to 80% likelihood.
(2) Radio/X-ray associated objects, totalling 75,858 without any other attribution. The displayed probability is calculated as described in the ARXA/QORG papers.
About 35,000 photometric quasars are 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 1,246,268 objects will yield
1,124,187 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):
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
2XMM/2XMMi: XMM-Newton, http://xmmssc-www.star.le.ac.uk
CXO: Chandra Source Catalog, http://cxc.cfa.harvard.edu/csc
CXOMP: Champ2 catalog, Kim M. et al, 2007, ApJS, 169, 401
CXOX: XAssist Chandra source list, http://xassist.pha.jhu.edu/zope/xassist
FIRST: VLA FIRST survey, sundog.stsci.edu
MGPS: Molonglo galactic plane survey, same attribution as SUMSS
NVSS: NRAO VLA sky survey, http://www.cv.nrao.edu/nvss
ST82: deep VLA obs on Stripe 82: http://www.physics.drexel.edu/~gtr/vla/stripe82
SUMSS: Sydney U. Molonglo, http://www.physics.usyd.edu.au/sifa/Main/SUMSS
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
Class
The HEASARC Browse object classification, based on the information
given in the broad_type parameter.