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GCN Circular 36413

EP240506a: TRT optical upper limit
2024-05-08T10:19:12Z (10 days ago)
S. Tinyanont at National Astronomical Research Institute of Thailand <>
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S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), S.Q. Jiang, Z.P. Zhu, X. Liu, Z. Fan, W.X. Li, N.C. Sun, Y.N. Wang, D. Xu (NAOC) report on behalf of a large collaboration:

We observed the field of EP240506a (Li et al., GCN 36405) using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Springbrook Observatory, New South Wales, Australia. Observations started at 09:53:36.57 UT on 2024-05-07, i.e., 1.20 day after the EP trigger, and 6 x 300 s R-band and 6 x 300 s I-band frames were obtained, respectively.

No uncatalogued optical transient is detected in the stacked R-band and I-band images within the 3 arcmin EP/WXT error circle (Li et al., GCN 36405), down to 3-sigma limiting magnitudes of R ~ 21.6 and I ~ 21.0, calibrated with Pan-STARRS sources in the field. Also there is no apparent brightening for the catalogued sources within the error circle.
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