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VII/273            The Half Million Quasars (HMQ) catalogue       (Flesch, 2015)

The Half Million Quasars (HMQ) catalogue. Flesch E.W. <Pub. Astron. Soc. Australia 32, 10 (2015)> =2015PASA...32...10F =2015yCat.7273....0F
ADC_Keywords: QSOs ; Active gal. nuclei ; Redshifts ; Magnitudes Keywords: catalogs - quasars: general Abstract: A quasar catalogue is presented with a total of 510764 objects including 424748 type 1 QSOs and 26623 type 1 AGN complete from the literature to 25 January 2015. Also included are 25015 high-confidence SDSS-based photometric quasars with radio/X-ray associations, 1595 BL Lac objects, and 32783 type 2 objects. Each object is displayed with arcsecond-accurate astrometry, red and blue photometry, redshift, citations, and radio and X-ray associations where present. Also, 114 new spectroscopically confirmed quasars are presented. Description: This is a compendium of all type-I QSOs and AGN, and BL Lac objects, complete from the literature to 25 January 2015. High-confidence (99%+) photometric SDSS candidates with radio/X-ray associations are included, plus type-II objects, which bring the total objects to 510764. Objects have been de-duplicated across source catalogs, and the earliest name and best redshift is presented for each. Astrometry is fixed onto a combined APM/USNO-B/SDSS optical background, and is accurate to within 1-2 arcsec in every case. Note: multiply-lensed images are listed as single objects. The catalog format is simple, each object is shown as one line bearing the J2000 coordinates, its name, red and blue optical magnitudes, PSF class, redshift, the citations for the name and redshift, plus up to four radio/X-ray identifiers where applicable. Questions/comments/praise/complaints may be directed to me at eric(at) File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file hmq.dat 182 510764 The Half Million Quasars catalogue refs.dat 159 2171 References
See also: : the HMQ Home Page VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010) V/134 : Atlas of Radio/X-ray associations (ARXA) (Flesch, 2010) Byte-by-byte Description of file: hmq.dat
Bytes Format Units Label Explanations
1- 11 F11.7 deg RAdeg Right ascension (J2000) (1) 13- 23 F11.7 deg DEdeg Declination (J2000) (1) 26- 50 A25 --- Name ID from the literature 52 A1 --- Cl [ABKQq] Classification of object (2) 53- 55 A3 --- Assoc [2RX ] Summary of associations for object (3) 57- 60 F4.1 mag Rmag ?=- Red optical magnitude (4) 62- 65 F4.1 mag Bmag ?=- Blue optical magnitude (4) 67- 69 A3 --- Comment Comment on optical object (5) 71 A1 --- R [1nx-] Red optical PSF class (6) 73 A1 --- B [1nx-] Blue optical PSF class (6) 75- 80 F6.3 --- z ? Redshift from the literature (7) 82- 85 I4 --- r_Name ? Reference for name, in refs.dat file 87- 90 I4 --- r_z ? Reference for redshift, in refs.dat file 92-113 A22 --- XName X-ray ID, if any (9) 115-136 A22 --- RName Radio ID, if any (9) 138-159 A22 --- Lobe1 Radio lobe ID or extra R/X ID, if any (9) 161-182 A22 --- Lobe2 Radio lobe ID or extra X-ray ID, if any (9)
Note (1): These are to 7 decimals which is too precise, but which accomodates a miniscule round-up which prevents inadvertent truncation by the user when converting to sexagesimal. Note (2): Classification of object as follows: Q = QSO from the literature, broad-line unresolved. 424748 of these. A = AGN, extended/Seyferts/low-luminosity. 26623 of these. B = BL Lac object, 1595 of these. q = high-confidence photometric QSO from SDSS NBCKDE/XDQSO, 25015 of these. K = type II objects, 32783 of these included for user reference. Note (3): Summary of associations for object as follows: R = Radio association displayed. X = X-ray association displayed. 2 = Double radio lobes displayed (declared by data-driven algorithm) Note (4): Optical data is from the APM (, USNO-A & USNO-B (, and the SDSS ( APM/USNO-A magnitudes have been recalibrated from the original values as documented in QORG (2004A&A...427..387F, Cat. J/A+A/427/387), so such USNO-A magnitudes are often used in preference to USNO-B. APM galaxies < mag 17.0 are usually shown too bright due to PSF modelling. Note: many SDSS magnitudes are extinction-"corrected" ∼0.3mag brighter than photometry. Note (5): Comment on optical object as follows: p = optical magnitudes are POSS-I O (violet 4100Å) and E (red 6500Å). 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 4800Å blue-green) from the POSS-II or UKST surveys. Red-blue color is less reliable because the plates were taken in different epochs, i.e. years apart. g = blue magnitude is SDSS green 4900Å. u = blue magnitude is SDSS ultraviolet 3850Å. b = blue magnitude is Vega 4400Å. v = red magnitude is visual, ie, white, 5500Å midpoint. i = red magnitude is infrared 7500Å. z = red magnitude is infrared z 8500Å. k = red magnitude is infrared k 22000Å. (not v/i/z/k) = standard red color 6500Å. + = variability nominally(*) detected for both red & blue. m = proper motion nominally(*) detected. a = object is an SDSS galaxy with AGN subclass. If also BROADLINE then HMQ class is 'A', otherwise 'K' (see note 2). ? = identification uncertain (quasar may be located elsewhere). (*) from USNO-B or Flesch & Hardcastle, 2004A&A...427..387F, section A.1 end Note (6): The APM, USNO-B, and SDSS provide PSF class, albeit using different criteria. These are shown here 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.) Note (7): Photometric redshifts are rounded to 0.1 z. Note (9): Four columns of Radio/X-ray detections are presented: * 1st column: best X-ray detection (i.e. highest probability association). * 2nd column: best core Radio detection. * 3rd column: a radio lobe if the associations (see note 3) show a "2", otherwise this is an additional radio or X-ray detection. * 4th column: a radio lobe if the associations (see note 3) show a "2", otherwise this is an additional X-ray detection. Legend of Radio/X-ray detections and catalog home pages: FIRST: VLA FIRST survey, 13Jun05 version, NVSS: NRAO VLA sky survey, SUMSS: Sydney U. Molonglo, MGPS: Molonglo galactic plane survey, same attribution as SUMSS ROSAT: catalogs home page: for: : 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, CXO: Chandra Source Catalog, CXOX: XAssist Chandra source list, 3XMM: XMM-Newton, XMMSL: XMM-Newton Slew survey, XMMX: XAssist XMM-Newton source list, 1SXPS: Swift X-ray Point Source catalog, Optical field solutions are calculated from the raw source positions of all these catalogs as described in my ARXA paper (2010PASA...27..283F, Cat. V/134).
Byte-by-byte Description of file: refs.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Ref [1/2171] Reference number 6- 11 I6 ---- NName ? Count of times used as a citation for the name. (excluding type 2) (1) 13- 18 I6 --- Nz ? Count of times used as a citation for the redshift. (excl. type 2) (1) 20- 38 A19 --- BibCode BibCode 40-159 A120 --- Details Standard authors list, year, journal volume & page, and sometimes a brief description or website
Note (1): The citation for the classification (e.g., that the object is a quasar) can be from either the name or redshift citation.
Acknowledgements: Eric Flesch, eric(at)
(End) Patricia Vannier [CDS] 12-May-2015
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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