The Half Million Quasars (HMQ) Catalogue
  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.
