2026ApJ...997..133W

Query : 2026ApJ...997..133W

2026ApJ...997..133W - Astrophys. J., 997, 133 (2026/February-1)

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

WAN Y., VIEIRA J.D., CHICHURA P.M., MACCARONE T.J., ANDERSON A.J., ANSARINEJAD B., ANUMARLAPUDI A., ARCHIPLEY M., BALKENHOL L., BARRY P.S., BENABED K., BENDER A.N., BENSON B.A., BIANCHINI F., BLEEM L.E., BOUCHET F.R., BRYANT L., CAMPHUIS E., CAMPITIELLO M.G., CARLSTROM J.E., CHANG C.L., CHAUBAL P., CHOKSHI A., CHOU T.-L., COERVER A., CRAWFORD T.M., DALEY C., DE HAAN T., DIBERT K.R., DOBBS M.A., DOOHAN M., DOUSSOT A., DUTCHER D., EVERETT W., FENG C., FERGUSON K.R., FICHMAN K., FOSTER A., GALLI S., GAMBREL A.E., GARDNER R.W., GE F., GOECKNER-WALD N., GUALTIERI R., GUIDI F., GUNS S., HALVERSON N.W., HIVON E., HOLDER G.P., HOLZAPFEL W.L., HOOD J.C., HRYCIUK A., HUANG N., KAPLAN D.L., KERUZORE F., KHALIFE A.R., KNOX L., KORMAN M., KORNOELJE K., KUO C.-L., LEVY K., LOWITZ A.E., LU C., LYNCH G.P., MANIYAR A., MARTSEN E.S., MENANTEAU F., MILLEA M., MONTGOMERY J., NAKATO Y., NATOLI T., NOBLE G.I., OMORI Y., OUELLETTE A., PAN Z., PASCHOS P., PHADKE K.A., POLLAK A.W., PRABHU K., QUAN W., RAHIMI M., RAHLIN A., REICHARDT C.L., ROUBLE M., RUHL J.E., SCHIAPPUCCI E., SIMPSON A., SOBRIN J.A., STARK A.A., STEPHEN J., TANDOI C., THORNE B., TRENDAFILOVA C., UMILTA C., VITRIER A., WHITEHORN N., WU W.L.K., YOUNG M.R. and ZEBROWSKI J.A.

Abstract (from CDS):

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 deg2 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 5σ 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 1031 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.

Abstract Copyright: © 2026. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Millimeter astronomy - Surveys - Galactic center - Transient sources - White dwarf stars

Status at CDS : Large table(s) will be appraised for possible ingestion in VizieR.

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 V* AR Sco EB* 16 21 47.2831986456 -22 53 10.385689092   14.94 14.75     M5+D? 141 0
2 NGC 6334 HII 17 20 53 -36 07.9           ~ 740 0
3 NGC 6357 OpC 17 24 44 -34 12.2           ~ 303 0
4 UCAC4 303-143267 Sy* 17 35 08.3086666176 -29 29 58.074023976   13.406 11.822 11.384   K4II/IIIe 7 0
5 SPT-SV J173508.3-292956 ev 17 35 08 -29 29.9           ~ 1 0
6 2MASS J17441724-2939444 ** 17 44 17.2511073312 -29 39 44.366884128           ~ 5 0
7 SPT-SV J174417.2-293942 ev 17 44 17 -29 39.7           ~ 1 0
8 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
9 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4970 3
10 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 2443 1
11 NGC 6618 OpC 18 20 47 -16 10.3           ~ 1700 0
12 V* AE Aqr CV* 20 40 09.1598959176 -00 52 15.055595220   12.46 10.40   10.191 K3-5IV/V 705 0
13 EM* LkHA 321 Or* 21 01 55.0706162280 +49 51 36.270580320   13.58 12.34 12.01   ~ 59 0

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