The ASAS-SN catalogue of variable stars X: discovery of 116 000 new variable stars using G-band photometry
Kochanek, C. S.; Stanek, K. Z.; Dong, Subo; Shappee, B. J.; Holoien, T. W. -S.; Prieto, J. L.; Jayasinghe, T.; Giles, W.; Thompson, T. A.; Christy, C. T.
United States, Chile, China
Abstract
The All-Sky Automated Survey for Supernovae (ASAS-SN) is the first optical survey to monitor the entire sky, currently with a cadence of ≲ 24 h down to g ≲ 18.5 mag. ASAS-SN has routinely operated since 2013, collecting ~ 2 000 to over 7 500 epochs of V- and g-band observations per field to date. This work illustrates the first analysis of ASAS-SN's newer, deeper, and higher cadence g-band data. From an input source list of ~55 million isolated sources with g < 18 mag, we identified 1.5 × 106 variable star candidates using a random forest (RF) classifier trained on features derived from Gaia, 2MASS, and AllWISE. Using ASAS-SN g-band light curves, and an updated RF classifier augmented with data from Citizen ASAS-SN, we classified the candidate variables into eight broad variability types. We present a catalogue of ~116 000 new variable stars with high-classification probabilities, including ~111 000 periodic variables and ~5 000 irregular variables. We also recovered ~263 000 known variable stars.