TITLE: GCN CIRCULAR NUMBER: 27107 SUBJECT: GRB 200216A: Swift/BAT detection and arcminute localization from GUANO DATE: 20/02/16 21:19:11 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), and Jamie Kennea (PSU) report: Swift/BAT did not trigger on GRB 200216A. The Fermi/GBM Flight-Position notice, distributed at T0+24 seconds, from the Fermi/GBM detected GRB 200216A (GCN. 27096) triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, in prep). The GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. Upon trigger by the Fermi notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of GRB 200216A. All the requested event mode data was delivered to the ground. In a ground analysis of the data, using the normal BAT imaging technique, we detect GRB 200216A with a SNR of 7.5. With a more sophisticated maximum likelihood analysis (DeLaunay et al., 2020 in prep.) on the event-mode data we detect GRB 200216A more confidently, with a square root of the test statistic (sqrt(TS)) of 15.4. The sqrt(TS) behaves similarly to SNR. The BAT ground-calculated position is RA, Dec = 311.4378, -11.6580 deg which is RA(J2000) = 311d 26' 16.08" Dec(J2000) = -11d 39' 28.8" with an uncertainty of 3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 40%. This arcminute location is consistent with the localization region distributed by the Fermi/GBM team (GCN. 27096). No XRT or UVOT follow-up will take place due to the source's proximity to the sun (1.2 hours). We encourage follow-up from instruments capable of observing near the sun.