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GCN Circular 33784

GRB 230512A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705565670)
2023-05-12T20:21:39Z (a year ago)
Tomas Ahumada at U. of Maryland <>
Tomas Ahumada (CIT), Harsh Kumar (IITB),  Viraj Karambelkar (CIT), Robert
Stein (CIT), Theophile du Laz (CIT), Igor Andreoni (UMD), Michael Coughlin
(UMN), Mansi Kasliwal (CIT), Simeon Reusch (DESY), Jannis Necker (DESY),
Shreya Anand (CIT), report on behalf of the ZTF collaboration:

We observed the localization region of the short bright GRB 230512A
(trigger 705565670, GCN 33778) 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; Bellm et al.,
2019; Graham et al., 2019) camera. ZTF covered 597.8 square degrees
corresponding to ~86% of the probability enclosed in the localization
region (GCN 33778), beginning 2 hours after the burst trigger time.
Exposures reached a median depth of 21 mag in the g-band and 20.9 mag in
the r-band.

Two sources were found within the 95% localization region, although all are
outside the 90% credible level. These are likely unrelated as they fall
outside the LAT localization circulated on GCN 33780:

| id           | alias   |       ra |     dec | mjd        | mag
 |filter      |
| ZTF23aajfoed | AT 2023ibn  | 295.8501 | 51.5420 | 60076.4041 | 18.89±0.08
| g          |
| ZTF23aajfilx | AT 2023ibo  | 267.5692 | 40.7678 | 60076.3839 | 20.22±0.19
| g          |

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
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). GROWTH India telescope is located at the Indian
Astronomical Observatory (Hanle), operated by the Indian Institute of
Astrophysics (IIA). GROWTH-India project is supported by SERB and
administered by IUSSTF, under grant number IUSSTF/PIRE
Program/GROWTH/2015-16 and IUCAA.

Tomás Ahumada (he/him)
Ph.D. Candidate
Department of Astronomy
University of Maryland, College Park
NASA <> Goddard Space Flight Center, Code 661
B.Sc. Astronomy, Pontificia Universidad Católica de Chile

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