GCN Circular 37930
Subject
EP241021a: Gemini-South detection of optical rebrightening
Date
2024-10-28T15:35:47Z (7 months ago)
From
Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>
Via
Web form
J. A. Quirola-Vasquez (Radboud Univ.), D. B. Malesani (DAWN/NBI & Radboud Univ.), A. J. Levan (Radboud), F. E. Bauer (PUC), P. G. Jonker (Radboud Univ.), report on behalf of a larger collaboration:
We observed the optical counterpart of EP241021a (Fu et al., GCN 37840; Gompertz et al., GCN 37835; Lipunov et al., GCN 37839; Fu et al., GCN 37842; Yang et al., GCN 37843; Li et al., GCN 37844; Li et al., GCN 37846; Zheng et al., GCN 37849; Moskvitin et al., GCN 37850; Pugliese et al., GCN 37852; Pérez-Fournon et al., GCN 37858; Bochenek et al., GCN 37869; Kumar et al., GCN 37875; Jin et al., GCN 37892), using the Gemini-South (GS) telescope equipped with the GMOS instrument.
We obtained 4x180 s exposures in the r-band, starting on 2024-10-28 at 00:21:06 UT, i.e., approximately ~6.8 days after the X-ray trigger. We detect the source at an r-band magnitude of ~21.90 AB mag, calibrated against nearby Pan-STARRS objects. Compared to both reports from the literature (e.g., Bochenek & Perley, GCN 37869; Busmann et al., GCN 37878) and our own data, this shows that the source has brightened. Such a brightening is reminiscent of that shown by EP240414a (Shubham et al. 2024, arXiv:2409.19070; van Dalen et al. 2024, arXiv:2409.19056), though occurring at a slightly later epoch.
We thank the staff of the Gemini-South for excellent support.