A survey of variable stars and outburst events with the 4-m ILMT

The 4-m International Liquid Mirror Telescope (ILMT) is Indias first optical facility dedicated to photometric and astrometric surveys. As a zenith-pointing telescope, it repeatedly observes the same strip of sky each night with a one-day cadence, making it ideal for time-domain studies such as the detection of transients, variable stars, and outburst events. To enable near real-time detection, the custom-developed PyLMT pipeline employs image subtraction techniques and integrates a convolutional neural network (CNN)-based real/bogus classifier to reduce false positives. A second CNN module classifies candidates based on host morphology, distinguishing between galactic and extragalactic sources. Originally developed for searching extragalactic transients, the pipeline has also identified nearly 1,800 detections corresponding to 500 different variable stars, including RR Lyrae, Delta Scuti, eclipsing binaries, long-period variables, and young stellar objects (YSOs). It has also detected several rare outburst events, such as cataclysmic variable (CV) eruptions. These transients are suitable for spectroscopic follow-up using the nearby 3.6-m Devasthal Optical Telescope (DOT), enabling accurate classification and physical characterization. In this work, I present a detailed overview of techniques developed for detecting variable stars as well as outburst events using a survey instrument like the ILMT. I also summarize some initial findings on the nature and physical properties of the variables/outbursts detected between November 2022 and May 2025.