MILLIQUAS - Million Quasars Catalog, Version 6.0 (15 March 2019)
Low-confidence or questionable objects (so deemed by their researchers) are not included in Milliquas. Additional quality cuts can be applied as detailed in Flesch 2015, PASA, 32, 10.
This version has the following changes from the previous edition:
(1) Quasars added from publications to 15 March 2019. (2) For ease of use, the "HMQ" citation (necessitating consultation of the HMQ catalog 2015-PASA-32-10 to identify the discovery article) is replaced by the HMQ-given 4-digit citation number. 30512 entries were changed. Now the HMQ references file can be directly consulted for any numeric citation. This makes Milliquas into a stand-alone catalog, so version # is reset to 6.0 . (3) positional fixes done on 9 legacy objects. (4) Where SDSS finds a different redshift for a LAMOST-discovered quasar, if the difference is >0.1z, the name & discovery credit are transferred to SDSS. This was done for 6 objects. (5) 42 AGN are dropped because their discovery paper Mauch & Sadler 2007, MNRAS,375,931 flagged those classifications as "not certain", also those 42 have neither stellar psfs nor secure (80%+) radio/X-ray associations. (6) The unseen Soviet BAL quasar "SBS 1401+566" is dropped. Its discovery paper 1986 Afanasiev/Erastova/Lipovetsky/Stepanian/Shapovalova, although cited as "in press" by Markarian/Stepanian/Erastova 1987-IAUS-121-25, was evidently never published. This object was only an artifact of the literature. (7) The quasar "Q 1409+732" is moved to the coordinates stated by its discovery paper Anderson & Margon 1987,Natur,327,125, where a suitable object resides. Confusion came from that paper's discrepant finding chart onto a plate flaw.The contents are relatively simple; each object is shown as one entry with the sky coordinates, its original name, object class, red and blue optical magnitudes, PSF class, redshift, the citations for the name and redshift, and up to four radio/X-ray identifiers where applicable.
Questions/comments/praise/complaints may be directed to Eric Flesch at firstname.lastname@example.org. If you use this catalog in published research, the author requests that you please cite it. The catalog can be cited as Milliquas v6.0 2019 update, Flesch E., 2015,PASA,32,10, which was the published version of this catalog.
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 made use of the SIMBAD database, operated at CDS, Strasbourg, France. http://simbad.u-strasbg.fr/simbad
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 3Aug09 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 artifacts. De-duplication of radio/X-ray detections improved. 3.9 30Jun14 Quasar data brought up to publications as at 30 June 2014. The XMM-Newton Slew Survey source catalog release 1.6 was added to X-ray data. The 1SXPS X-ray detections were being dropped; this was fixed and 21268 were included as a result. The Veron-Cetty & Veron Quasar Catalog (VCV) 13th edition (2010,A&A,518,10) was fully mapped into optical; corrections from this were incorporated. 4.0 05Aug14 Quasar data brought up to publications as at 5 August 2014. The threshold for inclusion of QSO candidates was raised to 80% confidence. This resulted in the loss of ~240,000 objects from v3.9, but it improved the confidence of use. XAssist v4 XMM-Newton and Chandra X-ray data was updated to 21-July-2014. 98 entries were found to be type II or not quasars, and so removed. The catalog layout was changed to conform better to the NED guide "Best Practices for Data Publication" by Marion Schmitz et al. (v1.2, 2013) in these ways: (a) all citations were changed to original discovery papers and no longer to VCV 13th edition or to NED and discovery citations are now indexed in a separate file; (b) quasar and radio/X-ray names which used to run together have been corrected to adhere to naming standards. 4.1 20Oct14 Quasar data brought up to publications as at 5 October 2014. The input values of RA and DEC used for this table were given in degrees rather than sexagesimal.Type 2 objects were included for the convenience of the users, but completeness of these is only about 95%. The type I objects are believed to be 100% complete from the literature. About 3000 SDSS "quasars" were removed as not quasars. These were auto-objects which were not taken up by the manual Paris files, and which were not given a subclass by the SDSS pipeline -- thus, the lowest quality objects. Another 2000 were reclassified as AGN or type 2 in this catalog. VCV mis-copied the redshifts from 2008 A&A,488,417 -- now fixed. QSOs & AGN re-partitioned by psf class and modified luminosity equation. Miscellaneous tweaks and fixes done when revealed by publication-related analysis. 4.2 06Dec14 Quasar data brought up to publications as at 6 December 2014. SDSS DR10/DR10Q and DR7/DR7Q data were reprocessed, yielding a few more quasars and using the DR10Q redshifts more as the current standard. Further adjustments were made to the luminosity equation separating QSOs from AGN, resulting in about 2000 AGN reclassified as QSOs. 18 new quasars from Dan Weedman, based on his re-analysis of the Weedman 1985 spectra in combination with NBCKDE photometric redshifts for those objects. 4.3 11Jan15 Quasar data brought up to publications as at 10 January 2015, including the newly-released SDSS-DR12 and SDSS-DR12Q (www.sdss.org). Approximately, 800 quasars sourced from the AGES catalog, Kochanek et al. (2012, ApJS, 200, 8). Approximately, 200 extra quasars added in a full round-up from NED and SIMBAD. 4.4 06Feb15 Quasar data brought up to publications as at 25 January 2015. Some reprocessing of the SDSS-DR12 and SDSS-DR12Q data. About 1000 type-1 objects reclassified to type-2. Photometric candidate likelihoods and redshifts were recalibrated using the SDSS-DR12Q quasars as the benchmark. 4.5 10May15 780 new quasars from LAMOST-DR1 (Luo et al. 2015, arXiv:1505.01570) were added. LAMOST-DR1 is a pipeline catalog with much provisional data, so the author selected the best-eligible objects only. LAMOST plans a manual (reliable) QSO catalog later this year. Also, NED/SIMBAD quasar data is included up to 9 May 2015. Citations were greatly simplified, referencing the recently published Half Million Quasars catalog (HMQ: Flesch E., 2015 PASA, 32, 10, arXiv:1502.06303) for smaller legacy citations while still citing large surveys like SDSS and 2QZ. A legend for the citations is given below, and the separate citations file is no longer needed as a result of this. 3XMM-DR5 (Rosen et al., 2015, arXiv:1504.07051) included in X-ray data. Also, high-confidence data from 2XMMi-DR3 is included, as acknowledged in section 8.2 of the Rosen paper (dropped 2XMMi-DR3 data recognized as valid). Minor fixes to optical data resulted in a few more radio/X-ray associations. 4.6 30Nov15 Additional QSO candidates were sourced from the new NBCKDE v3 catalog (Richards G.T. et al., 2015-ApJS-219-39) and a variability and refraction sourced catalog (Peters C.M. et al., 2015-ApJ-811-95). These added about 300,000 new candidates to Milliquas. Note that the NBCKDE v3 catalog uses different selection criteria from its predecessor, and so augments it rather than superseding it. The threshold for inclusion of QSO candidates was raised from 80% QSO-likelihood to 90%, so the catalog should be reliable even for spot checks. NED and SIMBAD listed quasars were included through 30-Nov-2015. 4.7 02Mar16 527 new QSOs were added from recent publications, including 33 new QSOs with z>5 of which 4 have z>6. The UV-Bright Quasar Survey (UVQS, T.R. Monroe et al., arXiv:1602.06255) was included with two mag-14 and 43 mag-15 QSOs plus many brighter AGN. 4.8 22Jun16 The Chandra ACIS source catalog (Wang S. et al., 2016,ApJS, 224,40) was added and new X-ray associations calculated. The 2nd RASS source catalog 2RXS (Boller Th. et al., 2016, A&A,588,103) replaced 1RXS for the most part, with significant differences in places. Radio/X-ray processing was tightened and data recalibrated to improve likelihood reliability, as part of a new radio/X-ray catalog in preparation. 23,727 radio/X-ray associated objects, recently dropped, were restored on the criterion that they are each 80%+ likely to be true quasars. This was done because this information is not found elsewhere. 4.8b 30Jul16 The 3XMM-DR6 X-ray source catalog was added and new X-ray associations calculated. The radio/X-ray data have been reprocessed in line with that of the Million Optical Radio/X-ray (MORX) Associations Catalog (Flesch 2016, PASA, 33, 52). 5.0 19Jun17 The J2000 coordinates now have 1/10th arcsecond precision, and the magnitudes have 1/100th mag precision, either from the original surveys or from the All-Sky Portable (ASP) optical catalog (arXiv:1705.05434). 5414 net QSOs/AGNs were added from recent surveys (listed below), notably AAOz, OzDES, LAMOST DR2, and a reload of AGES. The 3XMM-DR7 and XMMSL2-2.0 Slew X-ray source catalogues were added and new X-ray associations calculated. A few duplicates were removed. Notably, SDSS J131715.46+601533.1 was found to be a duplicate of SBS 1315+605. 5.1 30Jun17 Included full coverage of the Subaru-XMM Deep Field from multiple authors, LAMOST DR3, and other miscellaneous papers. 5.2 05Aug17 SDSS-DR14 and SDSS-DR14Q were added, using the processing rules from the Half Million Quasars catalog (HMQ: Flesch 2015, PASA, 32, 10). WISE quasar candidates were added from Secrest et al. 2015, ApJS, 221, 12. These are ~430,000 candidates over the whole sky for which 2-color optical objects were found within a 2-arcsec radius. They were processed into pQSOs from calibration against the SDSS-DR12Q multi-class superset, and photometric redshifts obtained using the four-color based method from the HMQ Appendix 2. The four colors used were B-R, R-W1, W1-W2, and W2-W3. Type-II narrow emission-line galaxies (NELGs, class='N') were added as the luminosity class corresponding to the type-I AGN galaxies. High-luminosity type-II NLAGN (class='K') correspond to the type-I quasars. The NLAGN/NELG divider is the same luminosity/psf function which separates QSOs from AGNs. Type-II NELGs include unquantified contamination by LINERs and probably a few starbursts which eluded removal, so it serves as a catch-all category presented for completeness, rather than as a strict type-II class. Small publications through 5 August 2017 were added. Positional fixes (of about 2 arcsec) were applied to ~150 objects. 5.3 12Sep18 Radio/X-ray association likelihoods calculated to a granularity of 1/10th of an arcecond for Chandra, XMM-Newton, and Swift X-ray source catalogs and the FIRST radio source catalog. All associations have been recalculated onto the APM/USNO-B optical background of Flesch 2017,PASA,34,25 (Figure 3). Radio/X-ray association likelihoods to faint SDSS sources not in the optical background were previously halved, based on the approximately doubled sky density of SDSS. This deduction was changed to be classed by PSF and red-blue color, consequentially most SDSS likelihoods were reduced more, often by 60%-90%. Associations to other faint objects were also reduced. The overall effect was that ~20,000 candidates fell below the 80% likelihood threshold for inclusion in Milliquas, and so were removed. Visually inspected quasars from the LAMOST DR3Q (Dong et al., 2018,AJ,155,189) and auto-quasars from the LAMOST DR4 (http://dr4.lamost.org/) were quality checked and a total of 10,624 quasars/AGN added to Milliquas. 5.4 17Oct18 Quasars from individual papers from August 2017 forward to 15 October 2018 have been added, plus some from a couple older papers. Quasar doublets are more carefully processed to show 2 quasars instead of 1. A few gravitiationally lensed images are added as type='L', in addition to the already-catalogued brightest one. These are added only where the optical data shows them in order to account for any radio/X-ray associations to them. The 3XMM-DR8 X-ray source catalog has been added and new X-ray associations calculated. A bug in v5.3 dropped radio/X-ray associations to some high-z quasars was fixed. 5.5 19Nov18 Quasars from publications to 14 November 2018 were added. The SDSS data were reprocessed to ensure DR14 data is used where available. Close quasar pairs and lens images processing was completed. 631 "unknown class" (type=U) objects (SDSS pipeline QSOs without subclass) were added. There are not usually accepted into Milliquas but they had probable radio/X-ray associations of p>80% which thus qualify them for inclusion. The SDSS pipeline redshift for these were included provisionally. The J2000 decimal round-up was increased to avert truncation. 5.6 17Dec18 Quasars from publications to 15 December 2018 were added. The 3rd release of SDSS-DR14Q (v4.4) was incorporated, adding ~300 quasars which had no astrometry in their earlier releases. All SDSS data was reprocessed to get rid of artifacts which had crept in. In preparation for LAMOST DR5Q (Yao et al 2018,arXiv:1811.01570), the LAMOST DR4 auto-quasars were demoted to quasar-candidates. LAMOST pipeline quasars were processed using the same rules as with SDSS pipeline. Removed 223 objects from Iovino/Clowes/Shaver,1996,A&AS,119,265 which had no quasar profile nor radio/X-ray/WISE associations, leaving 917 in Milliquas, resolving the cautionary note from HMQ(2015,PASA,32,10) section 2.B.4 end. 5.7 07Jan19 Quasars were added from publications to 7 January 2019, including LAMOST QSO DR5. The logic was tightened up for using SDSS SUBCLASS and ZWARNING fields to decide classifications for SDSS objects, including pipeline-only candidates. Milliquas was previously classifying all QSOs/AGN of z<0.1 as AGN. This boundary was moved to z=0.05 because of many core-dominated QSOs between z=0.05 and 0.1, e.g., IRAS 01267-2157 (SDSS J012910.99-214156.8) at z=0.93. HMQ (2015,PASA,32,10), section 5, discusses these luminosity-based boundaries. 22 objects from Boyle et al, 1990,MNRAS,243,18, classified by them as "possible" QSOs with "uncertain" redshifts, were removed from Milliquas. Positional fixes were done on ~90 legacy objects, mostly moves of <5 arcsec. 6.0 15Mar19 See list of changes above.
Flesch, E. The Million Quasars (MILLIQUAS) Catalog, Version 6.0 (15 March 2019) http://quasars.org/milliquas.htmSee 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/ XMM-Newton Catalog http://xmmssc.irap.omp.eu/ XMM-Newton Slew Survey http://www.star.le.ac.uk/~amr30/Slew
The designation of the source as taken from the literature. Nameless radio/X-ray associated objects here display the J2000 position in "HHMMSS.SS+DDMMSS.S" for the convenience of the user. If needing a name for it, just prefix this value with "MQ ", e.g., MQ J000001.64-251706.3.
The Right Ascension of the quasar candidate in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10-7 degrees in the original table. That is too precise, but it prevents inadvertent truncation by the user when converting to sexagesimal.
The Declination of the quasar candidate in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10-7 degrees in the original table. That is too precise, but it prevents inadvertent truncation by the user when converting to sexagesimal.
The Galactic Longitude of the quasar candidate. This parameter has been added by the HEASARC and is converted from the provided equatorial position.
The Galactic Latitude of the quasar candidate. This parameter has been added by the HEASARC and is converted from the provided equatorial position.
The classification of the object, where the following abbreviations are used:
Q = QSO, type-I broad-line core-dominated, 596043 of these. A = AGN, type-I Seyferts/host-dominated, 23705 of these. B = BL Lac object, 1649 of these. q = photometric quasar candidate from SDSS or WISE, 1266524 of these. ~1K are SDSS/LAMOST pipeline QSOs w/o subclass, with R/X associations. L = lensed quasar extra image, only 61 of these in this optical data. K = NLQSO, type-II narrow-line core-dominated, 5563 of these. N = NLAGN, type-II Seyferts/host-dominated, 33920 of these. Includes an unknown number of legacy NELGs/ELGs/LINERs for completeness. R = radio association displayed. X = X-ray association displayed. 2 = double radio lobes displayed (declared by data-driven algorithm).
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 (2004, A&A, 427, 387). 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 modeling. Integer magnitudes (e.g., 22.00) are estimates if both bands are integers or one band is empty. 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 than observed.
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/~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 (2004, A&A, 427, 387). 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 modeling. Integer magnitudes (e.g., 22.00) can be estimates if both bands are integer or one band empty. 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 than photometry.
This field contains coded information on the optical source properties, as follows:
p = optical magnitudes are POSS-I O (violet 4050A) and E (red 6400A). These are preferred because O is well-offset from E, and those plates were always taken on the same night, thus the red-blue color is correct even for variable objects. j = optical magnitudes are SERC J (Bj 4850A) and R (red 6400A) from the POSS-II or UKST surveys. Red-blue color is less reliable because the red and blue plates were taken in different epochs, i.e. years apart. b = blue magnitude is Vega 4400A (Johnson), red is 6400A (Cousins). g = blue magnitude is SDSS green 4900A, red is SDSS r 6200A. u = blue magnitude is SDSS ultraviolet 3850A. v = red magnitude is visual, i.e., white, 5500A midpoint. i = red magnitude is infrared 7500A. z = red magnitude is infrared z 8600A. r = red magnitude is r 6200A. (blank) = red alone is 6400A (Cousins), else they are r 6200A & g 4900A. + = variability nominally detected in both red/blue over multi-epoch data. m = proper motion nominally detected, from USNO-B. a = object is an SDSS galaxy with AGN subclass. If also BROADLINE then Milliquas class is 'A', otherwise 'N' (see broad_type).
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 band (fainter than plate depth, or confused, etc.)
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.)
The redshift of the object, taken from the literature as specified in the ref_redshift parameter. Photometric redshifts (for objects classified as 'q') are rounded to 0.1 z, except if pipeline redshifts are available from SDSS/LAMOST. The XDQSO catalog does not provide photometric redshifts, so those are provided either by NBCKDE or by this catalog using the four-color method detailed in Appendix 2 of the author's HMQ paper (2015,PASA,32,10). AllWISE photometric redshifts are similarly calculated using the four colors B-R, R-W1, W1-W2, and W2-W3, and are displayed where calculated as 50%+ (usually 80%+) likely to be true within 0.5z of the displayed redshift value.
A character code for the literature reference from which the name was taken is indicated below. The meaning of any 4-digit numerical code can be found in the references list of the author's Half Million Quasars Catalog (HMQ: Flesch 2015, PASA, 32, 10) at http://cdsarc.u-strasbg.fr/ftp/pub/cats/VII/273/refs.dat.
Code (No. of names, No. of redshifts): Reference 2dF (365,232): 2dF galaxy survey, Colless M. et al., 2001,MNRAS,328,1039 2MRS (7,2): Huchra et al., 2012,ApJS,199,26, http://tdc-www.harvard.edu/2mrs 2QZ (27515,24161): Croom S.M. et al., 2004,MNRAS,349,1397 2SLAQ (10387,8716): Croom S.M. et al., 2009,MNRAS,392,19 3FGL (16,16): Fermi cleanups, Paiano S. et al., 2017,ApJ,851,135 3FGL2 (22,22): Fermi cleanups II, Paiano S. et al., 2018,arXiv:1811.09125 3LAC (30,30): Fermi AGN v3, Ackermann M. et al., 2015,ApJ,810,14 3XLSS (25,25): The XXL Survey, Pierre M. et al., 2016,A&A,592A,1P 6dF (289,227): 6dF galaxy survey, Jones D.H. et al., 2009,MNRAS 399,683 AAOz (1491,1498): AAOmega XXL-South: Lidman C. et al., 2016,PASA,33,1 AGES (2046,2046): AGES survey, Kochanek C.S. et al., 2012,ApJS,200,8 AGNELL (2,3): DES lenses, Agnello A. et al., 2015,MNRAS,454,1260 AGNELA (4,4): SDSS J1433+6007 4-lens, Agnello A. et al., 2018,MNRAS,474,3391 AGNEL2 (13,13): VST-Gaia QSO pairs, Agnello A. et al., 2018,MNRAS,475,2086 AKARI (1,1): overlooked luminous quasar, Aoki K. et al., 2011,PASJ,63,457 ALMA (4,4): ALMA hi-z, Roberto Decarli R. et al., 2018,ApJ,854,97 ANGUIT (1,1): COSMOS lens, Anguita T. et al., 2009,A&A,507,35 ATel (4,4): Astronomers Telegraph posts held on http://www.pessto.org ATLAS (229,269): Mao M.Y. et al., 2012,MNRAS,426,3334 BAHM (24,24): dust-reddened QSOs, Banerji M. et al., 2015,MNRAS,447,3368 BASS (16,123): Swift-BAT AGN, Koss M. et al., 2017,ApJ,850,74 BERGHE (1,1): Pan-STARRS lens, Berghea C.T. et al., 2017,ApJ,844,90 BGGFC (4,4): COSMOS hi-z, Boutsia K. et al., 2018,ApJ,869,20 BQLS (17,17): BOSS QSO lenses & pairs, More A. et al., 2016,MNRAS,456,1595 BZCAT (5,4): Blazars catalog, Massaro E. et al., http://www.asdc.asi.it/bzcat C-COSM (180,180): Chandra COSMOS IDs, Marchesi S. et al., 2016,ApJ,817,34 ChaMP (191,188): Trichas M. et al., 2012,ApJS,200,17 DABAST (1,1): Diaz-Santos T. et al., 2018,Sci,362,1034 Dart (26,26): Heavily Obscured QSOs, Hviding R. et al., 2018,MNRAS,474,1955 DEEP (143,142): DEEP2, Newman J. et al., 2013,ApJS,208,5;deep.ps.uci.edu/DR4 DES (1,1): Dark Energy hi-z, Reed S.L. et al., 2015,MNRAS,454,3952 DESQQ (26,26): STRIDES lenses, Anguita T. et al., 2018,MNRAS,480,5017 DESQQ2 (12,12): STRIDES lenses, Treu T. et al., 2018,MNRAS,481,1041 DPeake (2126,3449): Double-peaked NELGs, Ge J.-Q. et al., 2012,ApJS,201,31 DR12 (18,19): Alam S. et al., 2015,ApJS,219,12, http://sdss.org/dr12 DR12Q (13,72): SDSS-DR12Q, Paris I. et al., 2017,A&A,597,79 DR14 (38719,50531): Abolfathi B. et al., 2018,ApJS,235,42, pipeline, data at https://data.sdss.org/sas/dr14/sdss/spectro/redux DR14Q (513026,526323): SDSS-DR14Q, Paris I. et al., 2018,A&A,613A,51, data at http://data.sdss.org/sas/dr14/eboss/qso/DR14Q DR7 (3,9): SDSS DR7, Abazajian K.N. et al., 2009,ApJS,182,543, files at http://classic.sdss.org/dr7/products/spectra/getspectra.html DR7Q (2089,329): SDSS Quasar DR7, Schneider D. et al., 2010,AJ,139,2360 data http://classic.sdss.org/dr7/products/value_added/qsocat_dr7.html DUHIZ (2,2): DECaLS-UKIRT hi-z, Wang F. et al., 2017,ApJ,839,27 DUz6 (18,18): DESI & UKIRT hi-z, Wang F. et al., 2018,arXiv:1810.11926 eHAQ (82,81): Extended High AV, Krogager J.-K., 2016,ApJ,832,49 ELQS-N (38,38): ELQS in NGC, Schindler J.-T. et al., 2018,ApJ,863,144 ELQS-S (126,126): ELQS in SGC, Schindler J.-T. et al., 2019,ApJ,871,258 FISCBA (1,1): HST lens, Fischer/Schade/Barrientos 1998,ApJ,503,L127 GAIA2 (263,263): Gaia DR2, Gaia Collaboration et al., 2018,A&A,616A,1, data as presented by SIMBAD, http://simbad.u-strasbg.fr/simbad GArcs (3,3): SDSS Giant Arcs lens, Dahle H. et al., 2013,ApJ,773,146 GLDD (1,1): Lensed QSO data-driven, Ostrovski F. et al., 2017,MNRAS,465,4325 GLIKMAN (29,29): red WISE QSOs, Glikman E. et al., 2018,ApJ,861,37 GLRED (1,1): lensed red QSO, Glikman E. et al., 2018,arXiv:1807.05434 HAQ (2,2): High AV serendipitous, Heintz K.E. et al., 2016,AJ,152,13 HAQC (1,1): High AV in COSMOS, Heintz K.E. et al., 2016,A&A,595,13 HEINTZ (1,1): dusty absorbed QSO, Heintz K.E. et al., 2018,A&A,615A,43 HIZ7.5 (1,1): QSO z=7.5, Bañados E. et al., 2018,Natur,553,473 IANTEG (1,2): INTEGRAL spectra X, Masetti N. et al., 2013,A&A,556A,120 IBIS (2,2): INTEGRAL/IBIS AGNs, Malizia A. et al., 2012,MNRAS,426,1750 IGMCP (10,10): IGM close pairs, Rorai A. et al., 2017,Sci,356,418 IKEDA (1,1): Ikeda H. et al., 2017,ApJ,846,57 IMS (1,1): IR medium-deep hi-z, Kim Y. et al., 2015,ApJ,813,35 IMS2 (10,11): IR medium-deep hi-z, Kim Y. et al., 2019,ApJ,870,86 KOVACS (1,1): bright QSO behind Milky Way, Kovács T. et al., 2019,RNAAS,3,3 LAMDR4 (159,2220): LAMOST-DR4, pipeline, http://dr4.lamost.org LAMQ1 (687,628): LAMOST QUASAR DR1, Ai Y.L. et al., 2016,AJ,151,24 LAMQ3 (6773,6663): LAMOST QUASAR DR3/DR2, Dong X.Y. et al., 2018,AJ,155,189 LAMQ5 (7998,7998): LAMOST QUASAR DR5/DR4, Yao S. et al., 2019,ApJS,240,6 LEMON (40,40): 24 Gaia lenses, Lemon C. et al., 2018,MNRAS,479,5060 LEMON2 (30,30): 22 Gaia lenses, Lemon/Auger/McMahon, 2019,MNRAS,483,4242 LIDMAN (1,1): SN Host Galaxy redshifts, Lidman C. et al., 2013,PASA,30,1 LIN (1,1): DES lens, Lin H. et al., 2017,ApJ,838,15 LIRAS (172,158): LoCuSS IR AGNs, Xu, L. et al., 2015,ApJS,219,18 LSSA (2,2): 2 lenses, Lucey/Schechter/Smith/Anguita, 2018,MNRAS,476,927 LUMIz5 (66,66): Luminous hi-z, Yang J. et al., 2018,arXiv:1810.11927 MALS-N (70,70): MEERKAT QSOs, Krogager J.-K. et al., 2018,ApJS,235,10 MFJC (52,51: McGreer I.D., Fan X., Jiang L. & Cai Z., 2018,AJ,155,131 MHH (2,2): variable quasars, Meusinger/Hinze/de Hoon, 2011,A&A,525A,37 MORX (49482,0): Million Radio/X-ray Associations, Flesch E., 2016,PASA,33,52 MQ (6781,622715): MILLIQUAS, original data in this catalog, Flesch E., 2019 MZZ (9,9): Marano B., Zamorani G., Zitelli V., 1988,MNRAS,232,111 NBCKDE (40823,40932): Richards G.T. et al., 2009,ApJS,180,67 NBCKv3 (529590,563871): NBCKDE v3, Richards G.T. et al., 2015,ApJS,219,39 OGLE2 (2,2): OGLE quasars, Kozlowski S. et al., 2018,arXiv:1810.08622 OSTROV (1,1): lensed, Ostrovski et al., 2019, in preparation OVRLAP (5,5): SDSS overlap hi-z QSOs, Jiang L. et al., 2015,AJ,149,188 OzDES (664,638): Dark Energy SN QSOs, Tie S.S. et al., 2017,AJ,153,107 P352-1 (1,1): P352-15, Bañados E. et al., 2018,ApJ,861L,14 PETERS (12896,12914): photo special, Peters C.M. et al., 2015,ApJ,811,95 PGC (13520,9): Principal Galaxy Catalogue, Paturel G. et al., 2003,A&A,412,45 PHILLI (1,0): MERLIN lens, Phillips P.M. et al., 2000,MNRAS,319,L7 PS1 (63,63): PAN-STARRS1 hi-z, Banados E. et al., 2016,ApJS,227,11 PS1hiz (1,1): Tang, Ji-Jia et al., 2017,MNRAS,466,4568 PS1MAZ (6,6): Mazzucchelli C. et al., 2017,ApJ,849,91 PSO (3,3): PAN-STARRS z-dropouts, Venemans B.P. et al., 2015,ApJ,801L,11 QPQ10 (70,70): Quasar pair DB, Findlay J.R. et al., 2018,ApJS,236,44 RBS (3,3): Laporte N. et al., 2017,ApJ,851,40 REQ4 (6,6): Reionization-Era quasars, Yang J. et al., 2018,arXiv:1811.11915 RLQ (4,3): Tuccillo D./Gonzalez-Serrano J.I./Benn C.R., 2015,MNRAS,449,2818 RSG (1,1): Dorn-Wallenstein T.Z. & Levesque E., 2017,IAUS,329,376 S82X (72,77): Stripe 82 AGN, LaMassa S.M. et al., 2019,arXiv:1902.09408 S82XRQ (8,8): Red Quasars, LaMassa S.M. et al., 2017,ApJ,847,100 SCULPT (2,3): Sculptor X-ray, Arnason R. M. et al., 2019,arXiv:1902.08635 SDLENS (3,3): SDSS Lenses, Williams P.R. et al., 2018,MNRAS,477L,70 SDSSHI (6,6): SDSS hi-z, Jiang L. et al., 2016,ApJ,833,222 SFM201 (1,1): Schulze S. et al., 2012,A&A,546,20 SHELLQ (33,33): Subaru hi-z, Matsuoka Y. et al., 2018,PASJ,70S,35 SHELQS (30,30): SHELLQS hi-z, Matsuoka Y. et al., 2018,ApJS,237,5 SHELz7 (1,1): SHELLQS z=7, Matsuoka Y. et al., 2019, arXiv:1901.10487 SMSSQ (2,2): SkyMapper hi-z, Zefeng Li Z. et al., 2018, arXiv:1805.03429 SPIN18 (1,1): KiDS-SQuaD lens, Spiniello C. et al., 2018,MNRAS,480,1163 SPIN19 (2,2): 2 lensed quasars, Spiniello C. et al., 2019,arXiv:1901.04414 SQLS (60,52): SDSS DR7 QSO Lens Search, Inada N. et al., 2012,AJ,143,119 SQUAD (13,13): UVES DB DR1, Murphy M.T. et al., 2019,MNRAS,482,3458 SSLENS (3,3): South sky lenses, Spiniello C. et al., 2018,arXiv:1811.01053 SUV (21,21): SDSS-ULAS/VHS QSOs, Yang J. et al., 2017,AJ,153,184 SXDF (39,39): Subaru-XMMDF redshifts, Simpson C. et al., 2012,MNRAS,421,3060 SXDS (309,308): Subaru-XMMDF spectra, Akiyama M. et al., 2015,PASJ,67,82 UFS (3,3): Dust reddened quasars, Glikman E. et al., 2013,ApJ,778,127 ULTRA (1,1): Ultraluminous hi-z, Wu, X.-B. et al., 2015,Nature,518,512 UVQS (435,517): UV QSOs, Monroe T.R. et al., 2016,AJ,152,25 VAHIZ (2,2): VST ATLAS hi-z, Carnall A.C. et al., 2015,MNRAS,451,16 VAHIZ2 (1,1): bright z>6 QSOs, Chehade B. et al., 2018,MNRAS,478,1649 VAHIZ3 (1,1): VST-ATLAS lens, Schechter P.L. et al., 2018,RNAAS,2b,21 VAQL (11,11): VST-ATLAS quasar systems, Schechter P.L. et al., 2017,AJ,153,219 VDES (8,8): VISTA Dark Energy Qsos, Reed S.L. et al., 2017,MNRAS,468,4702 VDES2 (2,2): more VHS-DES quasars, Reed S.L. et al., 2019,arXiv:1901.07456 VIKING (4,4): VIKING IR, Venemans, G.A. et al., 2015,MNRAS,453,2259 VIPERS (241,285): VIPERS PDR-2, Scodeggio M. et al., 2018,A&A,609A,84 VMC (34,34): Magellanic IR QSOs, Ivanov V.D. et al., 2016,A&A,588,A93 WARSAW (3,3): OGLE lens, Kostrzewa-Rutkowska Z. et al., 2018,MNRAS,476,663 WERTZ (1,1): Gaia GraL lens, Wertz O. et al., 2018,arXiv:1810.02624 WGD (2,2): DES/Gaia lenses; Agnello A. et al., 2018,MNRAS,479,4345 WISEA (447318,0): AllWISE QSO candidates, Secrest N. et al., 2015,ApJS,221,12 WISEHI (72,70): Hi-z QSOs from WISE, Wang F. et al., 2016,ApJ,819,24 WOLF1 (1,1): most ultraluminous QSO, Wolf C. et al., 2018,PASA,35,24 XDQSO (235757,0): SDSS-XDQSO, Bovy J. et al., 2011,ApJ,729,141 XLSS (306,119): Stalin C.S. et al., 2010,MNRAS,401,294 XMM2 (13,13): 2XMM-Newton cross-search, Combi J.A. et al., 2011,Ap&SS,331,53 XMMSMC (6,6): SMC quasars, Maitral C. et al., 2019,A&A,622A,29 XMSS (182,150): Barcons X. et al., 2007,A&A,476,1191 XWAS (490,449): Esquej P. et al., 2013,A&A,557,123 YQLF (25,25): deep CFHT QSOs, Yang J. et al., 2018,AJ,155,110 z6.51 (1,1): lensed quasar z=6.51, Fan X. et al., 2019,ApJ,870L,11 z7.02 (1,1): lensed quasar z=7.02, Wang F. et al., 2018,ApJ,869L,9The citation for the classification (e.g., that the object is a quasar) can be from either the name or redshift citation. Numeric references can be found in the HMQ (2015,PASA,32,10) references list.
A character code for the literature reference from which the redshift was taken, using the same rubric as used for the ref_name parameter (q.v.).
For a QSO candidate (type starting with q/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. Included candidates are those of 80%+ likelihood of being true quasars. For a known QSO (type = Q/A), Bl Lac type (type = B), or type-II (type = K/N), this field contains the percent chance that the shown radio/X-ray detection(s) is truly associated to it.
Candidates (objects without spectroscopic confirmation) originate from four types of sources:
(1) Photometric quasars from the SDSS-based NBCKDE/NBCKDE-v3/XDQSO/Peters quasar candidate catalogs. Those catalogs give calculated QSO probabilities (pQSOs) for their objects which are not reported here; instead, the author has calibrated those pQSOs against SDSS-DR12Q classified objects to produce the QSO likelihoods given here. The calibration method is detailed in the author's HMQ paper (2015, PASA, 32, 10), appendix 1. Included candidates are those of 80%+ likelihood of being true quasars.
(2) WISE-sourced candidates (from Secrest et al. 2015,ApJS,221,12) are presented by their authors with a bulk pQSO as an average figure, with no individual pQSOs given. These I have generated by matching WISE candidates to optical objects (within a two arcsecond radius) and then dividing them into four-color (the colors being B-R, R-W1, W1-W2, and W2-W3) subsets which are then calibrated against SDSS-DR12Q classified objects to yield the pQSO for each four-color subset.
(3) 56,264 radio/X-ray associated optical objects are presented only here in Milliquas, with pQSO calculated as described in the QORG paper (Flesch & Hardcastle, 2004,A&A,427,387), with no redshift displayed. However, an additional 353 such objects show pipeline redshifts from SDSS-DR14.
71,604 photometric quasars are also radio/X-ray associated, and the displayed probability figure combines the calibrated photometric QSO likelihood P1 and the radio/X-ray derived QSO likelihood P2 as
P = 1/(1+((1-P1)*(1-P2))/(P1*P2)).Over all objects, using the probability as expected yield, the 1,942,536 type-I Milliquas objects will yield 1,888,133 actual type-I quasars/AGNs.
The identification of the radio source associated with the quasar candidate, if any.
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) - 2RXP/2RXF: ROSAT PSPC (position sensitive proportional counter) - 1RXS: ROSAT RASS (all-sky survey, both bright & faint) 2RXS: 2nd RASS source catalog, Boller Th. et al., 2016,A&A,588,103 1WGA: White, Giommi & Angelini, http://wgacat.gsfc.nasa.gov/wgacat/wgacat.html CXO: Chandra Source Catalog v1.1, http://cxc.cfa.harvard.edu/csc CXOG: Chandra ACIS source catalog, Wang S. et al., 2016,ApJS,224,40 CXOX: XAssist Chandra source list, http://xassist.pha.jhu.edu/ 2XMM/2XMMi: XMM-Newton DR3, http://xmm.esac.esa.int/xsa/versions.shtml 3XMM: XMM-Newton DR8, http://www.cosmos.esa.int/web/xmm-newton/xsa XMMSL: XMM-Newton Slew Survey v2.0, same attribution as 3XMM XMMX: XAssist XMM-Newton source list, http://xassist.pha.jhu.edu/ 1SXPS: Swift X-ray Point Source catalog, http://www.swift.ac.uk/1SXPSOptical field solutions are calculated from the raw source positions of all these catalogs as described in the author's MORX paper (2016,PASA,33,52).
The identification of the radio lobe or an additional radio or X-ray identification associated with the quasar candidate, if any.
An additional identification of the radio lobe or an extra X-ray identification associated with the quasar candidate, if any.
The HEASARC Browse object classification, based on the information given in the broad_type parameter.