(Nobs mmed mmu msig mrms mchi2 mmax mrunmax mmin mrunmin mskew mskewErr mkurt mkurtErr), which are: the total number of observations in this band the median magnitude the mean magnitude the standard error for the mean (1.25 larger for the median) the root-mean-square scatter chi2 per degree of freedom (computed using the mean magnitude) the brightest magnitude the SDSS run ID of the brightest magnitude the faintest magnitude the SDSS run ID of the faintest magnitude the lightcurve skewness (calculated using the small sample skewness equation) the lightcurve skewness error the lightcurve kurtosis (calculated using the small sample kurtosis equation) the lightcurve kurtosis error
Intrinsic variability (sigma) is computed for each source in each band as
sigma = sqrt(rms2-xi2) for rms > xi (-99.99 otherwise),where the median photometric error, as a function of magnitude, is
xi = a + b*m + c*m2 + d*m3 + e*m4where m is the median dereddened magnitude of a source (this should really be done with uncorrected magnitudes, but quantitative differences are tiny) and (a,b,c,d,e) coefficients are
(6.27336, -1.60114, 0.153714, -0.00656245, 0.000105148) for the u band (2.13439, -0.540752, 0.0517104, -0.00219396, 3.48404e-05) for the g band (2.48331, -0.631346, 0.0605023, -0.002575, 4.10636e-05) for the r band (3.60719, -0.940377, 0.0919942, -0.00398576, 6.4533e-05) for the i band (8.06484, -2.16079, 0.217055, -0.00967042, 0.000161274) for the z band
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.
Thank you very much,
Branimir Sesar (1) Zeljko Ivezic (1) and the SDSS Collaboration (1) University of Washington
Please send us your question, comments or suggestions.