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\IBVShead{6064}{2 August 2013}

\IBVStitle{Variables from SDSS Stripe 82 region}

\IBVSauth{Sesar, B.$^1$; Becker, A.C.$^2$; Ivezi\'{c}, \v{Z}.$^{2,3}$}

\IBVSinst{Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA 91125, USA}
\IBVSinst{University of Washington, Department of Astronomy, P.O.~Box 351580, Seattle, WA 98195-1580, USA}
\IBVSinst{Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Budapest, Hungary}

\begintext

We wish to draw attention of the variable star community to a catalog of 67,507 candidate variable point 
sources selected from SDSS stripe 82 ($|{\rm Dec}|<$1\fdeg266 and R.A. in the range 20\hr 34\mm to 4\hr 00\mm; 
about 300 sq.deg.). Details about the construction and testing of the catalog are described in Ivezi\'{c} 
et al. (2007). Briefly, the selection criteria are: 
\begin{enumerate}
\item unresolved source in imaging data, and at least one band with photometric error below 0\fmm05,
\item SDSS processing flags BRIGHT, SATUR, BLENDED, or EDGE are not set,
\item at least 10 observations in the $g$ and $r$ bands are available,
\item the median $g$ band magnitude brighter than 20.5, 
\item ``most likely variable'': the root-mean-square scatter greater than 0\fmm05, 
    and $\chi^2_{dof} > 3$ in both $g$ and $r$ bands. 
\end{enumerate}

\IBVSfig{10cm}{6064-f1.ps}{Color-magnitude and color-color distributions of candidate 
variables from SDSS Stripe 82. The dots are color-coded according to the observed rms scatter
in the $g$ band (see the legend). Objects with $u-g<0.6$ are dominated by quasars.
Adapted from Fig. 3 in Ivezi\'{c} et al. (2007).}
\IBVSfigKey{6064-f1.ps}{SDSS Stripe 82 candidate variables}{}

The distribution of selected objects in SDSS color-magnitude and color-color diagrams
is shown in Fig.~1. This catalog and all light curves are publicly available\footnote{At the IBVS website and 
{\tt http://www.astro.washington.edu/users/ivezic/sdss/catalogs/S82variables.html}}. 
The catalog lists SDSS positions, median $ugriz$ photometry, number of observations, 
and some low-order statistics derived from light curves (including preliminary period
estimates). The median number of observations per band is about 30. On average, the 
objects were most often re-observed every two days (the SDSS-II SN Survey cadence), 
followed by 5-day, 10-day, and yearly re-observations (see Fig.~1 in Sesar et al. 2010). 
Examples of light curves for objects at the faint end of the sample are shown in Fig.~2. 

This dataset has not been fully explored yet. Initial analysis can be found in 
Sesar et al. (2007, 2010). As discussed there, this variable source catalog includes
both stars and quasars (about 10,000; for detailed analysis, see MacLeod et al. 2010). 
Among the stellar sample, RR Lyrae stars (about 500) are an especially useful probe of
the Galactic structure (Sesar et al. 2010). Except for the analysis of low-mass subsample by 
Becker et al. (2011), we are not aware of any other published detailed statistical analysis of 
eclipsing binary stars listed in this catalog. An M dwarf binary with extremely short period 
was analyzed in detail by Davenport et al. (2013). 

We note that, in addition to the catalog of variable sources from Stripe 82, a catalog of 
about million non-variable stars from the same sky region is also publicly available\footnote{{\tt
http://www.astro.washington.edu/users/ivezic/sdss/catalogs/stripe82.html}}. 
Thanks to averaging of multiple SDSS observations, the random photometric errors
are below 0\fmm01 for stars brighter than 19.5, 20.5, 20.5, 20, 18.5 magnitudes in $ugriz$, 
respectively (about twice as good as for individual SDSS runs). The spatial variation of 
photometric zeropoints is not larger than 0\fmm01 (rms). For more details, please
see Ivezi\'{c} et al. (2007). 

\IBVSfig{10cm}{6064-f2.ps}{Examples of $g$-band light curves for three RR Lyrae stars (with catalog IDs
equal to 4099, 74260, and 260984, from the top to the bottom panel, respectively)
with brightness ranging from the bright to the faint end of the sample. The
solid lines
show the best-fit templates from Sesar et al. (2010).}
\IBVSfigKey{6064-f2.ps}{RR Lyrae stars}{light curve} 
Acknowledgements:

\v{Z}.I. thanks the Hungarian Academy of Sciences for its support through 
the Distinguished Guest Professor grant No. E-1109/6/2012.



\references

Becker, A. C., Bochanski, J. J., Hawley, S. L., et al. 2011, ApJ, 731, 17

Davenport, J.R.A., Becker, A.C., West, A.A., et al. 2013, ApJ, 764, 62 

Ivezi\'{c}, \v{Z}., Smith, J.A., Miknaitis, G., et al. 2007, AJ, 134, 973

MacLeod, C.L., Ivezi\'{c}, \v{Z}., Kochanek, C.S., et al. 2010, ApJ, 721, 1014

Sesar, B., Ivezi\'{c}, \v{Z}., Lupton, R.H., et al. 2007, AJ, 134, 2236 

Sesar, B., Ivezi\'{c}, \v{Z}., Grammer, S., et al. 2010, ApJ, 708, 717 

\endreferences 

\IBVSedata{6064-t1.txt}
\IBVSdataKey{6064-t1.txt}{LINEAR variables}{starlist}
\IBVSecomment{Master catalog, the latest release (v1.1)}

\IBVSshortlink{http://www.konkoly.hu/pub/ibvs/6001/6064-d1.tar.gz}{6064-d1.tar.gz}
\IBVSdataKey{6064-d1.tar.gz}{LINEAR variables}{other}
\IBVSecomment{Light curve archive: as a gzipped ascii file (117 MB)}

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