Photometric calibration of the 4m ILMT data

Bhavya Ailawadhi; Talat Akhunov; Monalisa Dubey; Naveen Dukiya; Sara Filali; Paul Hickson; Priyanshi Kumari; Gokul Singh Mehra; Kuntal Misra; Vibhore Negi; Kumar Pranshu; Jean Surdej; Sarvesh Kumar Yadav

arXiv · 2611.04445

Photometric calibration of the 4m ILMT data

Bhavya Ailawadhi·Talat Akhunov·Monalisa Dubey·Naveen Dukiya·Sara Filali·Paul Hickson·Priyanshi Kumari·Gokul Singh Mehra·Kuntal Misra·Vibhore Negi·Kumar Pranshu·Jean Surdej·Sarvesh Kumar Yadav

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Abstract

The International Liquid Mirror Telescope (ILMT) is a 4-meter survey telescope continuously observing towards the zenith in the SDSS g', r', and i' bands. This survey telescope is designed to detect various astrophysical transients (for example, supernovae) and very faint objects like multiply-imaged quasars and low surface brightness galaxies. Ensuring accurate and stable calibration of supernova (SN) and quasar measurements is essential for studying their intrinsic variability and long-term brightness evolution. In this work, we present a dedicated calibration approach tailored for ILMT point-like object observations obtained in Time Delayed Integration (TDI) mode. Using ZTF reference sources cross-matched with the Pan-STARRS1 catalog, we derive robust photometric zero-points along the ILMT scan. This calibration procedure enables the production of consistent, high-precision SN and quasar light curves, suitable for variability studies, structure-function analysis, and future reverberation-mapping applications.

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Bhavya Ailawadhi, Talat Akhunov, Monalisa Dubey, Naveen Dukiya, Sara Filali, Paul Hickson, Priyanshi Kumari, Gokul Singh Mehra, Kuntal Misra, Vibhore Negi, Kumar Pranshu, Jean Surdej, Sarvesh Kumar Yadav. 2026-11-03. Photometric calibration of the 4m ILMT data. https://arxiv.org/abs/2611.04445

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