Detection of Millimeter-wavelength Flares from Two Accreting White Dwarf Systems in the SPT-3G Galactic Plane Survey

Year: 2026

Type: article

Abstract: Blind discoveries of millimeter-wave transient events in nontargeted surveys, as opposed to follow-up or pointed observations, have only become possible in the past decade using cosmic microwave background surveys. Here we present the first results from the SPT-3G Galactic Plane Survey—the first dedicated high-sensitivity, wide-field, time-domain, millimeter-wave survey of the Galactic Plane, conducted with the South Pole Telescope (SPT) using the SPT-3G camera. The survey field covers approximately 100 deg 2 near the Galactic center. In 2023 and 2024, this survey consisted of roughly 1500 individual 20 minute observations in three bands centered at 95, 150, and 220 GHz, with plans for more observations in the coming years. We report the detection of two transient events exceeding a 5 σ threshold in both the 95 and 150 GHz bands in the first 2 yr of SPT-3G Galactic Plane Survey data. Both events are unpolarized and exhibit durations of approximately 1 day, with peak flux densities at 150 GHz of at least 50 mJy. The peak isotropic luminosities at 150 GHz are on the order of 10 31 erg s −1 . Both events are associated with previously identified accreting white dwarfs. Magnetic reconnection in the accretion disk is a likely explanation for the observed millimeter flares. In the future, we plan to expand the transient search in the Galactic Plane by lowering the detection threshold, enabling single-band detections, analyzing lightcurves on a range of timescales, and including additional data from future observations.

Source: The Astrophysical Journal

DOI: 10.3847/1538-4357/ae2de8

Authors: Y. Wan, J. D. Vieira, P. M. Chichura, T. J. Maccarone, A. J. Anderson, B. Ansarinejad, A. Anumarlapudi, M. Archipley, L. Balkenhol, P. S. Barry, K. Benabed, A. N. Bender, B. A. Benson, F. Bianchini, L. E. Bleem, F. R. Bouchet, L. Bryant, E. Camphuis, M. G. Campitiello, J. E. Carlstrom, C. L. Chang, P. Chaubal, A. Chokshi, T.-L. Chou, A. Coerver, T. M. Crawford, C. Daley, T. de Haan, K. R. Dibert, M. A. Dobbs, M. Doohan, A. Doussot, D. Dutcher, W. Everett, C. Feng, K. R. Ferguson, K. Fichman, A. Foster, S. Galli, A. E. Gambrel, R. W. Gardner, F. Ge, N. Goeckner-Wald, R. Gualtieri, F. Guidi, S. Guns, N. W. Halverson, E. Hivon, G. P. Holder, W. L. Holzapfel, J. C. Hood, A. Hryciuk, N. Huang, D. L. Kaplan, F. Kéruzoré, A. R. Khalife, L. Knox, M. Korman, K. Kornoelje, C.-L. Kuo, K. Levy, A. E. Lowitz, C. Lu, G. P. Lynch, A. Maniyar, E. S. Martsen, F. Menanteau, M. Millea, J. Montgomery, Y. Nakato, T. Natoli, G. I. Noble, Y. Omori, A. Ouellette, Z. Pan, P. Paschos, K. A. Phadke, A. W. Pollak, K. Prabhu, W. Quan, M. Rahimi, A. Rahlin, C. L. Reichardt, M. Rouble, J. E. Ruhl, E. Schiappucci, A. Simpson, J. A. Sobrin, A. A. Stark, J. Stephen, C. Tandoi, B. Thorne, C. Trendafilova, C. Umilta, A. Vitrier, N. Whitehorn, W. L. K. Wu, M. R. Young, J. A. Zebrowski

Institutions: University of Illinois Urbana-Champaign, National Center for Supercomputing Applications, University of Chicago, Texas Tech University, Fermi National Accelerator Laboratory, The University of Melbourne, University of North Carolina at Chapel Hill, Centre National de la Recherche Scientifique, Institut d'Astrophysique de Paris, Sorbonne Université, Cardiff University, Argonne National Laboratory, SLAC National Accelerator Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, National Taiwan University, University of California, Berkeley, Université Paris Cité, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Université Paris-Saclay, Astrophysique, Instrumentation et Modélisation, High Energy Accelerator Research Organization, Canadian Institute for Advanced Research, Trottier Space Institute at McGill, McGill University, Princeton University, University of Colorado Boulder, University of California, Los Angeles, Michigan State University, University of California, Davis, Northwestern University, University of Wisconsin–Milwaukee, Case Western Reserve University, University of Toronto, NSF-Simons AI Institute for the Sky, Center for Astrophysics Harvard & Smithsonian

Language: English

Topic: Astrophysical Phenomena and Observations

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,499

Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, University of Pennsylvania, Ohio State University, California Institute of Technology, University of Chicago, University of Michigan, Science and Industry Endowment Fund, University of Portsmouth, National Centre for Supercomputing Applications, Australian Government, European Space Agency, University College London, European Commission, University of Nottingham, University of Sussex, Commonwealth Scientific and Industrial Research Organisation, Deutsche Forschungsgemeinschaft, Ministério da Ciência, Tecnologia e Inovação, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Financiadora de Estudos e Projetos, Government of Western Australia, Institut de Física d'Altes Energies, University of Illinois at Urbana-Champaign, Office of Science, Jet Propulsion Laboratory, University of California, Los Angeles, University of California, Davis, Science and Technology Facilities Council, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, High Energy Physics, Integrated Electronics Engineering Center, Binghamton University, Argonne National Laboratory, Fermilab, Lawrence Berkeley National Laboratory, SLAC National Accelerator Laboratory

OpenAlex ID: W7124871564