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GCN Circular 36189

EP240414a: Near-IR observations with NIRES and WINTER
2024-04-20T04:42:12Z (3 months ago)
Viraj Karambelkar at Indian Inst of Tech,Bombay <>
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Viraj Karambelkar (Caltech), Kaew Tinyanont (NARIT), Sam Rose (Caltech),
Tomas Ahumada (Caltech), Robert Stein (Caltech), Nathan Lourie (MIT),
Danielle Frostig (MIT), Geoffrey Mo (MIT), Robert Simcoe (MIT), Mansi
Kasliwal (Caltech)

We observed the location of the X-ray transient EP240414a (Lian et al., GCN
36091) in the K-prime band with the NIRES acquisition camera on the Keck II
telescope starting at UTC 2024-04-19T08:15:11. Our observations lasted for
100 seconds (25 sec, 4 coadds).

We detect the optical counterpart (GCN 36094, 36105, 36110, 36130, 36150,
36154, 36171, 36187) in the near-infrared Kp-band with m_Kp ~ 19.8 +/- 0.1
mag (AB). This suggests an r - Kp color of ~ 1 mag, based on r-band
photometry from 0.7 days earlier (reported in Wang et al. GCN #36171).

We also observed the location with the WINTER camera on the Palomar 40-inch
telescope (Lourie et al. 2021) in the J-band on UTC 2024-04-24T06:22:01 and
did not detect the source to a limit of m_J ~ 19 mag (AB).

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