Arecibo search for radio bursts following a previous SGR-like activity from SGR 1935+2154

ATel #13726; Nipuni Palliyaguru (TTU), Kshitij Aggarwal (WVU), Devansh Agarwal (WVU)
on 11 May 2020; 04:21 UT
Credential Certification: Nipuni Palliyaguru (nipuni.palliyaguru@ttu.edu)

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We observed the position of SGR 1935+2154 with the 305-m Arecibo telescope on two epochs following the SGR-like burst on 2019-10-04 detected by Fermi/GBM, which yielded a fluence of (7.142 +/- 0.576)E-8 erg/cm^2 at 10-300 keV (GCN Circular #25975). The first observation was on 2019-10-07 23:32:43.0 UTC for 0.35 hours at 1.4 GHz and 0.31 hours at 4.5 GHz. The second observation was on 2019-10-17 21:22:38.0 UTC for 0.81 hours at 1.4 GHz, 0.75 hours at 4.5 GHz, and 0.36 hours at 327 MHz. The data were dedispersed at 10-500 pc cm^-3, searched using Heimdall and candidates were run through the GPU accelerated convolutional neural network FETCH (Agarwal et al 2019) to distinguish between RFI and astrophysical signals. We also manually looked at all the candidates around the known dispersion measure of DM=332.8 pc cm^-3 (ATel #13681, #13684, #13699). We also searched for single pulses in the data using single_pulse_search.py (Ransom 2001) within a DM range of ~85 to ~580 pc cm^-3 with a DM step of 0.5 and a more refined search around the known DM. We did not detect any radio bursts in our data above a 10 sigma fluence upper limit of 0.04 Jy ms at 1.4 GHz, 0.07 Jy ms at 4.5 GHz and 0.35 Jy ms at 327 MHz. Our observations had the sensitivity to detect bursts such as the one recently reported by FAST (ATel #13699).