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GCN Circular 37118

Subject
X-ray Transient EP240807a: PRIME near-infrared upper limits
Date
2024-08-09T20:38:31Z (2 months ago)
From
Joe Durbak at UMD <gcn.joedurbak@gmail.com>
Via
Web form
O. Guiffreda (UMD), J. Durbak (UMD), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), K. De (MIT), S. B. Cenko (NASA/GSFC), Atri, S. (U Rome)

Following the Einstein Probe detection (GCN 37088), we observed the transient field in the J filter with PRIME ~21 hours after the EP/WXT detection.  The total exposure time of the observation was 1200s.  

We report that no new near-infrared detection was discovered within the EP/FXT (GCN 37097) error radius down to ~21.5 AB mag in J band.

At the position of the fast x-ray transient, we detect no uncatalogued source in J band. Using nearby VISTA Hemispherical Survey (VHS) stars for preliminary calibration we derive the following limiting magnitudes, not corrected for Galactic extinction:  

Filter | Mag(AB)        | Total exposure time (s) 
-------|----------------|-------------------------
J      | >21.5 +/- 0.1  | 1200

PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023).

We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.
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