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GCN Circular 36686

GRB 240615A: J-band upper limits from WINTER
2024-06-17T15:22:28Z (a month ago)
Viraj Karambelkar at Indian Inst of Tech,Bombay <>
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Viraj Karambelkar (Caltech), Geoffrey Mo (MIT), Robert Stein (Caltech),
Danielle Frostig (MIT), Tomas Ahumada (Caltech), Nathan Lourie (MIT),
Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report:

We observed the Swift-GUANO localization region of short GRB 240615A (GCN
36671, 36672, 36673, 36676, 36680, 36682, 36683) in the near-infrared
J-band with the Palomar 1-m telescope, equipped with the 1-square degree
WINTER camera (Lourie et al. 2020).

Our observations began at 2024-06-16T06:06:34 UTC (~12 hours after the GRB
trigger) and lasted for an hour. The images were processed using the WINTER
data reduction pipeline (,, with image subtraction performed
relative to J-band images from the UKIRT Hemisphere survey (Dye et al.,

We do not detect the XRT source (reported by GCN 36683) in our stacked and
subtracted images to a depth of J~19 mag (AB). No other new sources are
identified in our subtracted images, to a depth of J~19 mag (AB).

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 Lucile Packard Foundation, and the MIT Kavli Institute
for Astrophysics and Space Research.

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