TITLE:   GCN CIRCULAR
NUMBER:  24306
SUBJECT: LIGO/Virgo S190425z: Pre-discovery NIR limits of the UVOT transient candidate from Gattini-IR
DATE:    19/04/27 22:02:39 GMT
FROM:    Kishalay De at Caltech, GROWTH  <kde@astro.caltech.edu>

K. De (Caltech), M. Hankins (Caltech), S. M. Adams (Caltech), M. M.
Kasliwal (Caltech), M. Coughlin (Caltech), I. Andreoni (Caltech), S.
Anand (Caltech), L. Singer (NASA GSFC), T. Ahumada (UMD),  A. Moore
(ANU), J. Soon (ANU), M. Ashley (UNSW), T. Travouillon (ANU)

report on behalf of the Palomar Gattini-IR team and the larger GROWTH
(Global Relay of Observatories Watching Transients Happen)
collaboration

The Palomar Gattini-IR survey (Moore and Kasliwal 2019) observed the
location of the Swift UVOT counterpart candidate (GCN #24296) for the
BNS gravitational wave event S190425z (GCN #24168) on UT 2019-04-26
09:59 and UT 2019-04-25 at 10:54. Forced photometry on the images show
no source at the reported location down to a limiting magnitude of
15.2 AB mag in J band. The non-detections rule out bright infrared
emission from the source prior to the Swift detection.