The million quasars (Milliquas) catalogue, version 3.9 (2014)

MILLIQUAS v3.9 includes data up to 30 June 2014, including SDSS-DR10Q (Paris I. et al, 2013 arXiv:1311.4870). 1,262,723 objects are displayed, including 309,540 QSOs from the literature (type I only), 21682 AGN (ie, Seyferts for which the integrated disk outshines the core), 1578 Bl Lacs, 836798 photometric quasars from SDSS-based NBCKDE and BOSS, and 93125 radio/X-ray associated QSO candidates. A radio and/or X-ray identification is shown where applicable, plus, for the photometric and radio/X-ray associated objects, the probability of each being a true quasar. These expected yields total to 1,154,243 quasars, making MILLIQUAS a true million-quasar catalog.

Here is the ReadMe for the catalog, which gives details, file layout and references for the source data. Appendix A of the ReadMe gives details of the photometric selection and processing.

Quick browse of sample data here

Get the file (28 Mb zipped) here:  download


VCV Optical Catalog now available --21 July 2014

MILLIQUAS uses the Vëron-Cetty & Vëron Quasar Catalog (VCV: 2010,A&A,518,10) as the authority for pre-2010 quasars; however, these needed to be converted to long names and their astrometry shifted to their true optical positions. In the process many of the VCV quasars were found to be stars or galaxies, or duplicates, or not to exist. The counts are: 168,939 QSOs/AGN/BlLacs presented in VCV, of which 158,825 are found to be type I and thus used in Milliquas, 4119 are found to be type II, and 5995 are found not to be quasars.

The optical mapping of the VCV catalog is available here as 4 files equating to the four VCV files (table1=qsos, t2=bl lacs, t3=agn, t4=false). No good documentation for this, but the fixed width fields are:

1-15 VCV J2000, 18-35 VCV object name, 38 VCV optical flag, 40-45 VCV redshift, 48-51 VCV subclass, 53 VCV color, 54-57 VCV magnitude, 60-74 optical J2000, 77-100 optical name, 103 optical class, 105-110 redshift, 113-116 red magnitude, 119-122 blue magnitude, 125-127 comment on color, 129 red psf, 131 blue psf, 134-135 source catalog for name & class, 137-138 source catalog for redshift, 139-144 offset in arcseconds between VCV and optical positions, 147-202 comment on VCV-optical mapping, including large offsets and duplications, etc -- "paper" refers to my paper 2013,PASA,30,4 -- if the comment states "dup to XXXXX", then XXXXX is the VCV object name of the match -- if the comment states "dup to same name", then this VCV name is found as the optical name in another row.


Stars & Galaxies, radio/X-ray associated -- 15 February 2014

Milliquas is extracted from a larger database which includes stars & galaxies. Those stars & galaxies which are rated with a 80%-100% certain radio/X-ray association are presented below with the same file layouts as Milliquas. No documentation, but the citations are given in the Milliquas & ARXA ReadMe's. For confirmed objects (known to be galaxies or stars), the percentage column shows the chance that the radio/X-ray detection is truly associated to this object -- for candidates, it shows the percentage chance that this object is indeed a galaxy/star calculated from its photometry and radio/X-ray association.


The Atlas of Radio/X-ray Associations (ARXA, 2010 PASA, 27, 283) is here.


Eric Flesch, last updated 21 July 2014