Deep drilling in the time domain with DECam II: characterizing the light curves of candidates in the extragalactic fields

TL;DR

This paper releases and characterizes 2,020 optical light curves from the DECam deep drilling program, identifying various transient and variable objects in extragalactic fields to aid future time domain studies.

Contribution

It provides a large, publicly available dataset of light curves with preliminary classifications and analysis, supporting future research in transient astronomy.

Findings

Identification of diverse transients including supernovae and AGN

Comparison of observed transients with initial predictions

Discussion of challenges for upcoming large-scale surveys

Abstract

In this second paper on the DECam deep drilling field (DDF) program we release 2,020 optical gri-band light curves for transients and variables in the extragalactic COSMOS and ELAIS fields based on time series observations with a 3-day cadence from semester 2021A through 2023A. In order to demonstrate the wide variety of time domain events detected by the program and encourage others to use the data set, we characterize the sample by presenting a brief analysis of the light curve parameters such as time span, amplitude, and peak brightness. We also present preliminary light curve categorizations, and identify potential stellar variables, active galactic nuclei, tidal disruption events, supernovae (such as Type Ia, Type IIP, superluminous, and gravitationally lensed supernovae), and fast transients. Where relevant, the number of identified transients is compared to the predictions of the original proposal. We also discuss the challenges of analyzing DDF data in the context of the upcoming Vera C. Rubin Observatory and its Legacy Survey of Space and Time, which will include DDFs. Images from the DECam DDF program are available without proprietary period and the light curves presented in this work are publicly available for analysis.