GCN Circular 43905
Subject
EP260227a: Gemini-South optical observations
Event
Date
2026-03-03T10:58:44Z (a day ago)
From
Laura Cotter at University College Dublin <laura.cotter@ucdconnect.ie>
Via
Web form
R. A. J. Eyles-Ferris (Leicester), J. Quirola-Vasquez (Radboud), G. Corcoran (UCD), A. Martin-Carrillo (UCD), P. G. Jonker (Radboud), , A. J. Levan (Radboud), D. B. Malesani (DAWN/NBI and Radboud) report on behalf of a larger collaboration:
We observed the optical counterpart of the fast X-ray transient EP260227a (Wang et al., GCN 43869) with the Gemini-South telescope equipped with the GMOS-S instrument, obtained 12x60 s exposures in the r band starting at 2026-03-03 05:52:34 UT (t_mid = 81.9 hr).
In our stacked image, we detect a faint source coincident with the optical counterpart (Eyles-Ferris et al., GCN 43867; Li et al., GCN 43868; Fu et al, GCN 43873; Mandarakas et al., GCN 43874; Eyles-Ferris and Tanvir et al., GCN 43875; Malesani et al., GCN 43876; Eyles-Ferris et al., GCN 43877; Strausbaugh et al., GCN 43879; Bochenek et al., GCN 43880; Gassert et al., GCN 43881; Gupta et al., GCN 43884; Ma et al., GCN 43887; Eyles-Ferris et al., GCN 43888; Zhong et al., GCN 43891; Volnova et al., GCN 43894). In our preliminary photometry, we measure an AB magnitude of r = 24.80 +/- 0.33 calibrated to Pan-STARRS and not corrected for Galactic extinction. It is unclear at this stage whether this is continued transient emission or the underlying host galaxy.