TITLE: GCN CIRCULAR NUMBER: 39366 SUBJECT: GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61 DATE: 25/02/18 17:28:03 GMT FROM: Remo Ruffini at ICRA ruffini@icra.it

R. Ruffini, D. Berkimbayev, G. Vereshchagin, R. F. Mohideen Malik, N. Shynggyskhan, M.T. Mirtorabi, J.A. Rueda, Y. Wang, S.S. Xue, on behalf of the ICRANet team, report:

GRB 250215A / EP250215A was detected by Fermi (GCN 39327), Einstein Probe (GCN 39329), and SVOM (GCN 39333) at a redshift of z = 4.61 (GCN 39343). The burst duration is 2.3 s in the rest frame, corresponding to T_{90} = 13.4 s in the observer's frame (GCN 39342). The isotropic energy release is 3 \times 10^{53} erg, consistent with a BdHN I classification. This event shares similarities with GRB 220101A (GCN 37964), GRB 221009A (GCN 32828), and GRB 240825A (GCN 37536). Extended follow-up multi-wavelength observations are encouraged to fully characterize the BdHN I episodes: optical data for pulsar identification, X-ray observations to track the afterglow evolution, and GeV measurements to constrain the black hole energy.

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