Light curves in the NSVS (Northern Sky Variability Survey) are analyzed for their variability. The NSVS covers the optical magnitude range from 8 to 15.5 for the Northern Sky. If light curves have good photometric data points more than 15, these light curves are included in our analysis. The total number of light curves in the current database is 16,189,040. This online database provides variability analysis and objects' spatial matching to other databases such as SIMBAD, IRAS, AKARI, WISE, 2MASS, SDSS, and GALEX. In future, we will have more results of cross-correlations to future data.

(from http://www.astro.ucla.edu/~wright/WISE/)

We apply clustering methods to separate variable candidates from non-variable objects. The method is explained in the following papers:

Detecting variability in massive astronomical time series data - I. Application of an infinite Gaussian mixture model (Shin et al., 2009, MNRAS, 400, 1897)
Detecting Variability in Massive Astronomical Time-Series Data II: Variable Candidates in the Northern Sky Variability Survey (Shin et al., 2012, AJ, 143, 65)

In particular, the second paper explains all variable candidates found in the NSVS data with their associations to other observation data. Please, cite the above papers when you use our analysis results.