Newer edition of SDSS Quasar Catalog available

As of March 2005, the third edition of the SDSS Quasar Catalog, based on DR3 data and containing 46,420 objects, is available. This new catalog supersedes all previous editions, which are retained at their old URLs for reference. Go to the Third edition of the SDSS Quasar Catalog.

Second edition of the SDSS Quasar Catalog

The DR1 quasar catalog is described in Schneider et al. 2003, AJ accepted (scheduled to appear in the December 2003 issue and available at astro-ph/0308443). The catalog contains 16,713 objects from DR1 that have i-band absolute magnitudes brighter than -22 and contain at least one broad emission line. The catalog was created by inspecting all spectra that were either targeted as quasar candidates, or classified as a quasar by the spectroscopic pipelines.

SDSS Quasar Catalog redshifts supersede those in other DR1 data products

Because of the re-inspection of the spectra, the DR1 Quasar Catalog provides the most reliable classifications and redshifts of SDSS quasars. The classifications in the catalog supersede those found in other DR1 data products accessible from the DR1 data access page, as well as from the EDR quasar catalog (see below). The improved classifications will be fed back into other data products for future data releases.

The DR1 Quasar Catalog is not a statistical sample

There are two reasons:

1. It includes objects from all categories of target selection in SDSS, not just those selected as quasar candidates.

2. While the catalog does contain target selection flags which make it easy to remove non-quasar candidates, the quasars in the catalog were all selected during the commissioning period. This period saw 12 different versions of the target selection software; none of the quasars in the catalog were selected using the final quasar target selection algorithm described in Richards et al. 2002, which was the 13th.

   The catalog contains both the TARGET selection flags used to select spectroscopic targets, and the BEST selection flags obtained by applying the final target selection version (sometimes to better photometric data obtained later during the survey - see target and best coverage). However, in addition to dropping catalog entries which were not selected by the final version, one has to account for missing quasar candidates, i.e., those identified by the final target selection algorithm but without spectroscopic observations.

These caveats aside, the selection of UV excess quasars has remained reasonably uniform. These constitute 80% of the objects in the DR1 Catalog. Changes to the target selection algorithm were primarily aimed at improving the effectiveness of the identification of z> 2.5 quasars.

Download the DR1 Quasar Catalog

The catalog is available in the following formats:

• ASCII table
  • dr1qso.dat (5.1 MB)
  • dr1qso.dat.gz (gzipped, 1.1MB)
• fits binary table
  • dr1qso.fits (3.4 MB)
  • dr1qso.fits.gz (gzipped, 1.2MB)

The catalog files have been generated on August 28, 2003.

EDR quasar catalog

For historical reference, the EDR quasar catalog is available at the MAST EDR site.