GCN Circular 41557
Subject
EP250827a: Gemini-South redshift z = 1.613
Event
Date
2025-08-27T09:24:15Z (8 days ago)
From
Jonathan Quirola at Radboud University <jaquirola1990@gmail.com>
Via
Web form
A. J. Levan (Radboud and Warwick), J. A. Quirola-Vasquez (Radboud), P. G. Jonker (Radboud), G. Corcoran (UCD), D. B. Malesani (DAWN/NBI and Radboud), R. A. J. Eyles-Ferris (Leicester), A. Martin-Carrillo (UCD), report on behalf of a larger collaboration:
We observed the location of the optical counterpart (Levan et al., GCN 41554) to EP250827a (Hua et al., GCN 41553) with Gemini-South and the GMOS instrument using the B480 grating and a 1 arcsec slit. Four 300 s exposures were obtained. Observations began on 2025 Aug 27 at 08:51 UT, approximately 71 min after the EP trigger time. The data was reduced using DRAGONS.
Several metallic absorption lines (due to e.g. Fe II and Mg II) at a redshift of z = 1.613 are present, suggesting the FXT lies at this redshift or beyond.
We thank the staff of Gemini, especially K. Silva, for their outstanding work in rapidly obtaining these observations.