The ASAS-SN catalogue of variable stars X: discovery of 116 000 new variable stars using <i>G</i>-band photometry

Christy, C. T.; Jayasinghe, T.; Stanek, K. Z.; Kochanek, C. S.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W-S; Prieto, J. L.; Dong, Subo; Giles, W.
2023
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
DOI
10.1093/mnras/stac3801
The All-Sky Automated Survey for Supernovae (ASAS-SN) is the first optical survey to monitor the entire sky, currently with a cadence of less than or similar to 24h down to g less than or similar to 18.5mag. ASAS-SN has routinely operated since 2013, collecting similar to 2000 to over 7500 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 similar to 55 million isolated sources with g < 18 mag, we identified 1.5 x 10(6) 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 similar to 116 000 new variable stars with high-classification probabilities, including similar to 111 000 periodic variables and similar to 5 000 irregular variables. We also recovered similar to 263 000 known variable stars.