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A search for millimeter-wave transient sources in the galactic plane with SPT-3G

Event Type
Seminar/Symposium
Sponsor
Department of Astronomy
Location
134 Astronomy Building
Virtual
wifi event
Date
Feb 3, 2025   12:00 - 1:00 pm  
Speaker
Yujie Wan
Contact
Daniel Franco
E-Mail
danielf9@illinois.edu
Phone
217-300-6769
Views
4
Originating Calendar
Astronomy Journal Club

Recent cosmic microwave background (CMB) experiments have opened the millimeter-wave (mm) regime of the electromagnetic spectrum to time-domain astrophysics. While mm observations have been conducted in the past, this is the first time that transient events have been blindly discovered in non-targeted surveys, as opposed to follow-up or pointed observations. The dominant source of time variability in the mm extragalactic sky is blazars, while in the Galaxy, the mm transient signals are dominated by stellar flares, which can be $\sim 10^5$ times more energetic than flares from our own Sun. The South Pole Telescope (SPT) has recently conducted the first mm-wave time-domain survey of the Galactic plane. Currently, this survey consists of approximately 500 observations covering 98 square degrees of the Galactic plane from 2023 to 2024, with plans for more observations in the coming years. The survey measures intensity and linear polarization in three bands centered at 90, 150 and 220 GHz. In this talk, I will present the first results from this survey. We have detected two transient events above a threshold of 5$\sigma$ in both 95 and 150GHz bands. Both events are associated with white dwarf binaries. Future analysis will involve lowering the detection threshold to $3\sigma$ and improving the transient pipeline to be sensitive to timescales of minutes.

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