The newly built International Liquid Mirror Telescope (ILMT) in India has detected its first supernova, SN 2023af. The discovery was announced on the preprint server on November 8 arXivIt proves that ILMT will be able to detect hundreds of new supernovae in the coming years.

Supernovae (SNe) are powerful, bright star explosions that can help us better understand the evolution of stars and galaxies. Astronomers divide supernovae into two groups based on their atomic spectra: type I and type II. Type I SNe has no hydrogen in its spectra, while Type II SNe exhibits hydrogen spectral lines.

ILMT It is a 4-meter diameter surface-to-air telescope located at the Devasthal Observatory in Nainital, India. Designed for purely photometric/astrometric direct imaging. Astronomers hope that ILMT will help them discover many new transient objects, such as gamma-ray burst supernovae. The telescope saw first light on April 29, 2022, and is currently in the final stages of commissioning.

Now, a team of astronomers led by Brajesh Kumar of the Aryabhatta Observing Research Institute (ARIES) in India reported on March 9, 2023 that ILMT had detected its first supernova, SN 2023af, which was first discovered two months ago. The team made follow-up observations of SN 2023af with the ILMT, as well as the 3.6-meter Devasthal Optical Telescope (DOT) and the 1.3-meter Devasthal Fast Optical Telescope (DFOT).

“During the commissioning phase of ILMT, supernova (SN) 2023af was identified in the ILMT field of view. Researchers noted that SN was also monitored through ILMT and DOT.

The team obtained a light curve extending up to 110 days after the discovery of SN 2023af. Initial ILMT results show that hydrogen lines and metal lines are clearly visible in the spectrum of this supernova.

Based on the light curve and spectral characteristics of SN 2023af, the authors of the article assume that this object is a type IIP supernova. In general, Type II-Plateau supernovae (SNe IIPs) remain bright (on the plateau) for a long time after the maximum. This plateau in the standard SN IIP light curve typically lasts for about 100 days.

SNe IIPs, such as SN 2023af, are thought to originate from protostars that retained significant amounts of hydrogen (more than three solar masses) before exploding as core-collapse supernovae (CCSNe).

However, astronomers added that more observations are needed to confirm that SN 2023af is classified as type IIP. They explained that it is currently impossible to draw a definitive conclusion about the length of this supernova’s plateau due to the sparseness of data points.

In summary, the researchers stated that future ILMT observations will provide a unique opportunity to discover and study different types of supernovae each year, leading to the discovery of hundreds of new star explosions.