Rapid follow-up observations of infant supernovae with the Gran Telescopio Canarias

TL;DR

This study demonstrates the importance of rapid spectroscopic follow-up of infant supernovae using the Gran Telescopio Canarias to capture early explosion signatures, aiding in understanding supernova progenitors and explosion mechanisms.

Contribution

It presents a dedicated rapid-response spectroscopic program that successfully obtained early spectra of supernovae, highlighting the need for such efforts in conjunction with wide-field surveys.

Findings

Spectra of 10 supernova candidates were obtained, with half being thermonuclear and half core-collapse.

Most supernovae were observed within six days of explosion, including two within 48 hours.

The study emphasizes the necessity of rapid-response spectroscopy for early supernova characterization.

Abstract

The first few hours of a supernova (SN) contain significant information about the progenitor system. The most modern wide-field surveys that scan the sky repeatedly every few days can discover all kinds of transients in those early epochs. At such times, some progenitor footprints may be visible, elucidating critical explosion parameters and helping to distinguish between leading explosion models. A dedicated spectroscopic classification programme using the optical spectrograph OSIRIS mounted on the Gran Telescopio Canarias was set up to try to obtain observations of supernovae (SNe) at those early epochs. With the time awarded, we obtained spectra of 10 SN candidates, which we present here. Half of them were thermonuclear SNe, while the other half were core-collapse SNe. Most (70\%) were observed within the first six days of the estimated explosion, with two being captured within the first 48\,hr. We present a characterization of the spectra, together with other public ancillary photometry from the Zwicky Transient Facility (ZTF) and the Asteroid Terrestrial-impact Last Alert System (ATLAS). This project shows the need for an accompanying rapid-response spectroscopic programme for existing and future deep photometric wide-field surveys located at the right longitude to be able to trigger observations in a few hours after the discovery of the SN candidate.