The zenithal 4-m International Liquid Mirror Telescope: a unique facility for supernova studies

TL;DR

The 4-m International Liquid Mirror Telescope (ILMT) at Devasthal is a unique zenith-pointing facility designed for high-cadence supernova observations, capable of detecting and monitoring new supernovae through repeated nightly scans.

Contribution

This paper introduces the ILMT as a novel liquid mirror telescope optimized for supernova detection and detailed analysis of its expected observational capabilities and supernova detection rates.

Findings

ILMT can reach magnitudes of 22.8, 22.3, and 21.4 in g', r', and i' bands.

High cadence observations enable dense multi-band supernova light curves.

Expected supernova detection rates are calculated for various cosmological scenarios.

Abstract

The 4-m International Liquid Mirror Telescope (ILMT) will soon become operational at the newly developed Devasthal observatory near Nainital (Uttarakhand, India). Coupled with a 4k $\times$ 4k pixels CCD detector and TDI optical corrector, it will reach approximately 22.8, 22.3 and 21.4 magnitude in the $g'$, $r'$ and $i'$ spectral bands, respectively in a single scan. The limiting magnitudes can be further improved by co-adding the consecutive night images in particular filters. The uniqueness to observe the same sky region by looking towards the zenith direction every night, makes the ILMT a unique instrument to detect new supernovae (SNe) by applying the image subtraction technique. High cadence ($\sim$24 hours) observations will help to construct dense sampling multi-band SNe light curves. We discuss the importance of the ILMT facility in the context of SNe studies. Considering the various plausible cosmological parameters and observational constraints, we perform detailed calculations of the expected SNe rate that can be detected with the ILMT in different spectral bands.