The ASAS-SN catalogue of variable stars I: The Serendipitous Survey

TLDR: The All Sky Automated Survey for Supernovae (ASASAS-SN) is the first optical survey to routinely monitor the whole sky with a cadence of 2-3 days down to V$\lesssim17$ mag as discussed by the authors.

Abstract: The All-Sky Automated Survey for Supernovae (ASAS-SN) is the first optical survey to routinely monitor the whole sky with a cadence of $\sim2-3$ days down to V$\lesssim17$ mag. ASAS-SN has monitored the whole sky since 2014, collecting $\sim100-500$ epochs of observations per field. The V-band light curves for candidate variables identified during the search for supernovae are classified using a random forest classifier and visually verified. We present a catalog of 66,179 bright, new variable stars discovered during our search for supernovae, including 27,479 periodic variables and 38,700 irregular variables. V-band light curves for the ASAS-SN variables are available through the ASAS-SN variable stars database (this https URL). The database will begin to include the light curves of known variable stars in the near future along with the results for a systematic, all-sky variability survey.