We conduct a systematic search for transients in three years of data (2017-2019) from the Atacama Cosmology Telescope (ACT). ACT covers 40 percent of the sky at three bands spanning from 77 GHz to 277 GHz. Analysis of 3-day mean-subtracted sky maps, which were match-filtered for point sources, yielded 29 transients detections. Eight of these transients are due to known asteroids, and three others were previously published. Four of these events occur in areas of with poor noise models and thus we cannot be confident they are real transients. We are left with 14 new transient events occurring at 11 unique locations. All of these events are associated with either rotationally variable stars or cool stars. Ten events have flat or falling spectra indicating radiation from synchrotron emission. One event has a rising spectrum indicating a different engine for the flare.
@article{arxiv.2303.04767,
title = {The Atacama Cosmology Telescope: Systematic Transient Search of 3-Day Maps},
author = {Yaqiong Li and Emily Biermann and Sigurd Naess and Simone Aiola and Rui An and Nicholas Battaglia and Tanay Bhandarkar and Erminia Calabrese and Steve K. Choi and Kevin T. Crowley and Mark Devlin and Cody J. Duell and Shannon M. Duff and Jo Dunkley and Rolando Dunner and Patricio A. Gallardo and Yilun Guan and Carlos Hervias-Caimapo and Adam D. Hincks and Johannes Hubmayr and Kevin M. Huffenberger and John P. Hughes and Arthur Kosowsky and Thibaut Louis and Maya Mallaby-Kay and Jeff McMahon and Federico Nati and Michael D. Niemack and John Orlowski-Scherer and Lyman Page and Cristobal Sifon and Maria Salatino and Suzanne T. Staggs and Cristian Vargas and Eve M. Vavagiakis and Yuhan Wang and Edward J. Wollack},
journal= {arXiv preprint arXiv:2303.04767},
year = {2024}
}