TITLE: GCN CIRCULAR NUMBER: 40064 SUBJECT: EP250404a: AKO Optical Afterglow Detection DATE: 25/04/04 18:35:28 GMT FROM: Mohammad Odeh at Al Khatim Observatory M44 mshodeh@gmail.com

Mohammad Odeh (Al-Khatim Observatory, AKO, operated by the International Astronomical Center in Abu Dhabi, UAE), and Shaikha Alshamsi and Nidhal Guessoum (American University of Sharjah, UAE), report:

We observed the field of EP250404a detected by EP (Hu et al., GCN 40051), using our 0.36m f/7.7 robotic telescope. The observation session began on 04 April 2025 at 15:47 UT and continued until 16:56 UT, with a midpoint at 16:22 UT, approximately 2 hours after the trigger.

We obtained multiple 180-second exposures using the Ic filter. The optical afterglow was clearly detected at:

R.A. (J2000): 08:20:14.59

Dec. (J2000): +35:31:42.3

Our detection is consistent with the results of (Jiang et al., GCN 40052; Perez-Garcia et al., GCN 40053; Du et al., GCN 40058; Konno et al., GCN 40063).

The following observation was calculated using the Atlas catalogue as a reference:

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ObsTime (mid), Exposure (sec), Filter, Mag

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2025-04-04T16:21:38Z, 20 x 180s (stacked), Ic, 17.5 +/- 0.35

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The magnitude is not corrected for galactic extinction.

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