Non-detection of impulsive radio emission from SGR J1935+2154 coincident with a short gamma-ray burst
ATel #14770; W. Farah (SETI Institute "SI" / University of California, Berkeley "UCB"), A. W. Pollak (SI / UCB), A. P. V. Siemion (SI / UCB), F. Antonio (Qualcomm), G. Singh (SI), S. Schoultz (SI), J. Hickish (Real-time Radio Systems Ltd / SI), R. Maddalena (Green Bank Observatory), D. DeBoer (SI / UCB), C. Shumaker (SI), M. Masters (SI)
on 9 Jul 2021; 23:16 UT
Credential Certification: Wael Farah (wfarah@seti.org)
Subjects: Radio, Soft Gamma-ray Repeater, Transient, Fast Radio Burst
As part of an ongoing survey of fast radio transient sources, the Allen Telescope Array (ATA) had begun radio observations of the field of SGR J1935+2154 (RA [hours], Dec [degrees] = 19.582, 21.897) on UTC 2021-07-09-08:58:46.000 following the recent activity of the source (Ridnaia et al. 2021, GCN 30418; Cai et al., GCN 30415). The observations were conducted at a center frequency of 1500 MHz, with a total bandwidth of 720 MHz, using the incoherent sum of 10 antennas. Dual-polarization data from the antennas were split into 2880 frequency channels each 0.25 MHz wide and detected and integrated to a time resolution of 480 microseconds. The data from the 10 dual-polarization signals were then incoherently summed and processed using the GPU-accelerated dedispersion algorithm, HEIMDALL (Barsdell 2012).
The observing block fortuitously coincided with a short burst detection recorded with GECAM on 2021-07-09T11:17:55.000 (Cai et al. 2021, GCN 30430). No radio counterpart of the high-energy burst was detected with the fast radio transient search pipeline at the ATA. We thus place an early-estimate upper limit on radio fluence of 15 Jy-ms (9-sigma detection threshold, 1ms pulse).
Additional observations at the ATA are on-going.
The Allen Telescope Array is a 42-element radio interferometer located at the Hat Creek Radio Observatory in Northern California. The facility is fully operated by the SETI Institute.
