SPT-210826 - South Pole Telescope Begins Public Alert System, Reports Detection of a Millimeter-Band Flaring Source

ATel #14875; Allen Foster (CWRU), Sam Guns (UC Berkeley), SPT-3G Collaboration
on 26 Aug 2021; 21:11 UT
Credential Certification: Nathan Whitehorn (nwhitehorn@physics.ucla.edu)

Tweet

The South Pole Telescope Collaboration reports: The 3rd-generation receiver on the South Pole Telescope (SPT-3G) detects a flaring millimeter point source at RA = 15.10494d, DEC = -43.95403d (estimated positional uncertainty of 15 arcseconds). Detectable emission began in the week of June 20 2021, with a global detection significance of ~6.8 sigma and continues to rise in week-long averages with a current significance of ~8.8 sigma. Peak emission is currently (as of the most recent week ending on Aug 23rd) 13.2 +/- 1.9 mJy (95 GHz), and 12.2 +/- 2.2 mJy (150 GHz). At the time of this alert, emission from this source is rising. SPT-3G will continue to monitor this source at hour- to day-long intervals. Average quiescent flux at this position in 2020 measured via SPT-3G is 5.7 +/- 0.5 mJy (95 GHz), and 5.0 +/- 0.6 mJy (150 GHz) suggesting a factor of 2 increase in millimeter-band luminosity. This source may be associated with SPT-SJ010023-4357.1, which is located at a distance of 15 arcseconds from the SPT-3G source and measured by SPT-SZ to have average flux densities 7.3 +/- 2.3 mJy (95 GHz) and 5.1 +/- 1.4 mJy (150 GHz) between Sept 2010 and October 2011. There is also a nearby (~2 arcseconds) quasar candidate source XMMSL2 J010025.1-435716/WISEA J010025.17-435713.5. All flux calibrations quoted here are preliminary and are believed to be accurate to 20%. Further information including lightcurves and an updated catalog of SPT transient detections can be found at https://pole.uchicago.edu/public/data/transients/. The South Pole Telescope is a 10-meter telescope designed for observations of the cosmic microwave background located at Amundsen-Scott South Pole Station and supported by the National Science Foundation and the US Dept. of Energy. The SPT online transient program providing data in this telegram is supported by NSF grants AST-1716965 and OPP 1852617, and observes 1500 square degrees of the southern sky at 95, 150, and 220 GHz with an average revisit cadence of 12 hours. For more details on the SPT transient program and survey strategy, please see https://arxiv.org/abs/2103.06166.

South Pole Telescope Transients Public Data