TITLE: GCN CIRCULAR NUMBER: 28981 SUBJECT: GRB201130A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 628407054) DATE: 20/12/02 15:41:48 GMT FROM: Shreya Anand at GROWTH Caltech Simeon Reusch (DESY), Igor Andreoni (Caltech), Harsh Kumar (IITB), Tomas Ahumada (UMD), Varun Bhalerao (IITB), Shreya Anand (Caltech), Eric Bellm (UW), Michael Coughlin (UMN), Mansi Kasliwal (Caltech), Erik Kool (OKC), Ana Sagues Carracedo (OKC), Leo Singer (NASA/GSFC), and Robert Stein (DESY) on behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: We observed the localization region of the short GRB201130A (trigger 628407054) detected by the Gamma-Ray Burst Monitor (GBM) on the Fermi satellite with the Palomar 48 inch telescope equipped with the 47 square degree Zwicky Transient Facility (ZTF) camera. We obtained a series of g-band images covering about 400 square degrees beginning at 12:28 UT on 2020 Nov 30 (about 7 hours after the burst trigger time) for two consecutive nights. This corresponds to ~75% of the probability enclosed in the region of the GRB localization map that was unocculted by the Earth for the Fermi GBM (GCN 28965). Exposures reached a g-band median depth of 20.5 mag and 20.3 mag in the first and second night. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC (Masci et al. 2019). We queried the ZTF alert stream using Kowalski (Duev et al. 2019) and AMPEL (Nordin et al. 2019). We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-matched our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018), and apply machine learning algorithms (Duev et al. 2019, Mahabal et al. 2019). We require no spatially coincident ZTF alert to be issued before the detection time of the GBM trigger. We found no candidates consistent with a potential GRB counterpart within the localization region. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019).