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GCN Circular 36248

LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
2024-04-23T08:10:26Z (3 months ago)
Viraj Karambelkar at Indian Inst of Tech,Bombay <>
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Viraj Karambelkar (Caltech), Geoffrey Mo (MIT), Robert Stein (Caltech),
Nathan Lourie (MIT),

Danielle Frostig (MIT), Tomas Ahumada (Caltech), Robert Simcoe (MIT), and
Mansi Kasliwal (Caltech)

We observed the localization region of the LVK trigger S240422ed (GCN
36236) with the 1.2 sq. degree WINTER camera on the Palomar 1-m telescope
(Lourie et al. 2021). We obtained images in the near-IR J-band of the Bilby
sky map (GCN 36240). Our observations began at 2024-04-23T03:04 UTC, ~5.5
hours after the GW event time, and lasted for ~2.5 hours.

Our observations covered ~14% of the localization probability, and achieved
a 5-sigma depth ranging between m_J = 16 - 17 mag (AB) depending on the
sensor temperature. The observations have been reported to TreasureMap
(Wyatt et al. 2020).

The images were processed through the WINTER data reduction pipeline
implemented using mirar (, We cross-matched all sources with
the alert stream from the Zwicky Transient Facility (GCN 36246). We found
153 candidates and rejected them as variable stars. Further analysis is

WINTER (Wide-field INfrared Transient ExploreR) is a partnership between
MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF
AAG, the David and Lucille Packard Foundation, and the MIT Kavli Institute
for Astrophysics and Space Research.

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