The Atacama Cosmology Telescope: Systematic Transient Search of Single Observation Maps

TL;DR

This paper presents a systematic search for astrophysical transients using Atacama Cosmology Telescope data from 2017-2022, detecting 34 events mostly linked to Galactic stars, and discusses implications for models of gamma-ray burst shocks.

Contribution

The paper introduces a novel pipeline for transient detection in single observation maps across multiple frequencies, expanding the search for diverse astrophysical transient phenomena.

Findings

Detected 34 transient events, mostly associated with Galactic stars.

Identified a nova and a flaring active galactic nucleus.

Did not detect reverse shock emission from gamma-ray bursts.

Abstract

We conduct a systematic search for astrophysical transients using data from the Atacama Cosmology Telescope (ACT). The data were taken from 2017 to 2022 in three frequency bands spanning 77 GHz to 277 GHz. In this paper we present a pipeline for transient detection using single observation maps where each pixel of a map contains one observation with an integration time of approximately four minutes. We detect 34 transient events at 27 unique locations. All but two of the transients are associated with Galactic stars and exhibit a wide range of properties. We also detect an event coincident with the classical nova YZ Ret and one event consistent with a flaring active galactic nucleus. We notably do not detect any reverse shock emission from gamma ray bursts, a non-detection that may be in tension with current models.