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GCN Circular 24223

LIGO/Virgo S190425z: ZTF pre-merger limits on PS1 candidates
2019-04-26T14:00:03Z (5 years ago)
Michael Coughlin at Caltech/LIGO <>
Authors: Michael W. Coughlin (Caltech), Shreya Anand (Caltech), Tomas
Ahumada (UMD)

On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of
Observatories Watching Transients Happen (GROWTH) collaborations

We have analyzed the list of objects reported in Smith et al. (24210),
and examined ZTF alerts for the same objects. We find that 7 of the
events listed below have recent, previous detections with ZTF prior to
the gravitational wave event trigger time and are likely unrelated to the
BNS event S190425z (The LIGO Scientific Collaboration and the Virgo
Collaboration, GCN 24168).

Name            PS Name    ZTF Name
AT2019ebu   PS19pp      ZTF19aasbgll
AT2019ebw  PS19pq      ZTF19aasazok
AT2019ecc   PS19pw      ZTF19aapwgpg
AT2019eck   PS19qe      ZTF19aapfrrw
AT2019ecl    PS19qg      ZTF19aasgwnp
AT2019ebr   PS19qj       ZTF18aaoxrvr
AT2019ebo   PS19qn     ZTF19aarpgau

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; TTU USA;
Tokyo Tech, Japan; IIT-B, India; IIA, India; LJMU, UK 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 filtering and follow-up co-ordination
is being undertaken by the GROWTH marshal system (Kasliwal et al.

Michael Coughlin

David and Ellen Lee Prize Postdoctoral Fellow
LIGO Laboratory
West Bridge, Rm. 257
California Institute of Technology
MC 100-36
Pasadena, CA 91125

phone: +1 952 836 7113
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