Fourth edition of the SDSS Quasar Catalog
The DR5 quasar catalog is described in Schneider et
al. 2007, AJ 134, 102. The catalog contains 77,429 objects from
DR5 that have apparent i-band PSF magnitude fainter than
15, absolute i-band magnitudes brighter than -22, contain
at least one emission line or are unambiguously broad absorption line
quasars, and have highly reliable redshifts. 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 data
products
Because of the re-inspection of the spectra, the DR5 Quasar Catalog
provides the most reliable classifications and redshifts of SDSS
quasars. The classifications in the catalog supersede those found in
other data products accessible from the data
access page, as well as from the DR3, DR1 and EDR quasar
catalogs. The improved classifications will be fed back into other
data products for future data releases.
The DR5 Quasar Catalog is not a statistical sample
There are two reasons:
- It includes objects from all categories of target selection in SDSS, not just those
selected as quasar candidates.
While 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), use of the BEST data
produces a different set of quasar candidates than the
TARGET version that was used to define
spectroscopic plates, even for those parts of the sky that were
targeted using the final quasar target
selection algorithm described in Richards
et al. 2002. If one uses the BEST photometry
to define a statistical sample, not only must one drop catalog
entries which were not selected by the final version, but one also has to
account for missing quasar candidates, i.e., those identified by
the final target selection algorithm but without spectroscopic
observations. A forthcoming paper will discuss the construction
of a statistical quasar sample in detail.
These caveats aside, the selection of UV excess quasars has
remained reasonably uniform. These constitute 89% of the
color-selected objects, and 63% of the total DR5 Catalog. Changes to
the target selection algorithm were primarily aimed at improving the
effectiveness of the identification of z> 2.5
quasars.
Download the DR5 Quasar Catalog
The catalog is available in the following formats:
- ASCII table
- fits binary table
The catalog files have been generated on March 28, 2007.
Last modified: Wed Jan 9 12:00:19 CET 2008
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