SCAT Data Release 1: 1810 optical spectra of 1330 transients

TL;DR

The paper introduces the first data release of the SCAT survey, providing 1810 spectra of 1330 transients, along with light curves, host galaxy data, and classifications to aid real-time transient analysis.

Contribution

It presents a comprehensive dataset of transient spectra, light curves, and host galaxy information, enhancing resources for transient classification and redshift studies.

Findings

Spectra cover diverse transient classes including supernovae and nuclear transients.

Half of the host galaxies have newly measured redshifts, mostly low-luminosity dwarfs.

The dataset supports development of real-time photometric classification pipelines.

Abstract

We present the first data release (DR1) of the Spectroscopic Classification of Astronomical Transients (SCAT) survey, covering the first $\approx 5$ years of observations (March 2018 - January 2023). DR1 includes 1810 spectra of 1330 transients, which we sort into broad spectroscopic classes including supernovae (SNe), transients originating in galactic nuclei, and stellar variability. We collect multi-filter light curves from imaging surveys and fit them with phenomenological models to estimate peak brightnesses and the time of explosion/first-light. Extragalactic transients are matched to candidate host galaxies, and we compare host-galaxy luminosities and projected offsets by SN type. SNe appear to be a reliable way to augment the redshift coverage of nearby ($z\lesssim 0.1$) galaxies in tandem with dedicated redshift surveys. We present new redshifts for roughly half of the SN host galaxies, most of which are low-luminosity dwarfs similar to the Magellanic Clouds ($M_r \gtrsim -18$ mag). This set of transient spectra, light curves, luminosities, redshifts, and host galaxies offers an excellent testbed for real-time photometric/light curve classification pipelines in the modern era of deep and large-area surveys. We conclude with a brief discussion of the provided data products and status of the SCAT survey.