The SDSS Stripe 82 Variable Source Catalog


Master catalog, the latest release (v1.1): as a gzipped ascii file (2.8 MB).

Light curve archive: as a gzipped ascii file (117 MB). (see below for more information)

This catalog lists positions, median ugriz photometry, and some light curve information, for 67,507 candidate variable point sources from SDSS stripe 82 (|Dec|<1.266 deg and RA in the range 20h 34m to 4h 00m; about 300 sq.deg.). Details about the construction and testing of the catalog are described in Ivezic et al. 2007 (Astronomical Journal, 134, 973). Here is a quick selection summary:

 1) unresolved source in imaging data, at least one band with 
    photometric error below 0.05 mag
 2) processing flags BRIGHT, SATUR, BLENDED, or EDGE are not set
 3) at least 10 observations in the g and r bands
 4) the median g band magnitude brighter than 20.5 
 4) most likely variable: root-mean-square scatter > 0.05 mag 
    and chi2pdf > 3 in both g and r bands 
These sources dominate those that were rejected when constructing The SDSS Stripe 82 Standard Star Catalog. However, note that sources from the "gray" selection zone are not included in either catalog.

IMPORTANT: Compared to the previous (Sesar et al. 2007) catalog, these data are more extensive because they include both SDSS-I and SDSS-II observations, while the Sesar et al. (2007) catalog was based only on SDSS-I observations.

After 8 header lines that start with #, the catalog data file includes one line per source, and each line lists (in this order):

ID: is a 7-character long integer ID: e.g. 7904669; used to name 
    files with light curves (see below)
ra, dec: equatorial coordinates (decimal degrees, J2000)
P: period (days); determined as the most likely period returned
   by MACHO's Supersmoother algorithm (of course, there is no
   guarantee that a source is truly periodic, or that this period
   is not aliased - be very careful and look at phased light curves)
r: r band magnitude (corrected for ISM extinction using SFD maps)
ug, gr, ri, iz: SDSS colors (corrected for ISM extinction)
gN, gAmpl: the number of data points and amplitude (max-min) in the g band
rN, rAmpl, iN, iAmpl: same as above, but in the r and i bands
zQSO: redshift if spectroscopically confirmed SDSS quasar, -9.9 if not
MiQSO: absolute magnitude in the i band if quasar, -9.9 if not

Each source has its light curves listed separately, in file named LC_ID.dat, where ID comes from the master file described above. Directory with all 67,507 files is available as a compressed archive, AllLCs.tar.gz (117 MB) These files list MJD (not sorted), band (ugriz), magnitude (uncorrected for ISM extinction) and its error. Unreliable measurements are commented out (lines starting with #; they were not removed to signify that an image/observation does exist).

If you are interested in RR Lyrae stars, please let me know as Branimir Sesar already selected a complete sample based on this data set, and also derived ugriz templates.

For more details, in case of problems, etc., send email to Z. Ivezic (ivezic@astro.washington.edu). Technical and other information about SDSS can be found on www.sdss.org.

Referencing

The reference entry for this catalog is Ivezic, Z., Smith, J.A., Miknaitis, G., et al. 2007, Astronomical Journal, 134, 973. In addition, we would greatly appreciate if you add the standard SDSS acknowledgement to your paper:

Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web Site is http://www.sdss.org/.

The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington.


Please send us your comments or suggestions.


Version 1.0 from June 26, 2009