GCN Circular 37246
Subject
GRB 240821A: LCO optical observations
Date
2024-08-23T12:59:04Z (4 months ago)
From
luca.izzo@inaf.it
Via
Web form
L. Izzo (INAF-OACn and DARK/NBI) and D. B. Malesani (DAWN/NBI and Radboud Univ.) report:
We observed the field of GRB 240821A (Fermi GBM Team, GCN #37219; Cangemi et al., GCN #37220; He et al., GCN #37226; Murphy et al., GCN #37232; Dalessi et al., GCN #37239) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located at the Cerro Tololo Inter-American Observatory, Chile. Observations started on 2024 August 22 at 09:39 UT (15.05 hr after the GRB trigger). We obtained a series of 8x120 s images in the SDSS-i filter.
We centered the telescope at the coordinates provided by SVOM/GRM (Cangemi et al., GCN #37220), giving us the possibility to cover the entire error region recommended by the SVOM team.
Given the proximity of a bright Moon, the final stacked image is contaminated by moonlight. We did not detect any new source within the several X-rays counterparts error regions reported by EP-FXT (Turpin et al., GCN #37230) up to a limit of i = 20.7 mag. For some of the X-ray detections provided by the EP-FXT, objects are visible within the EP error circles but are consistent with archival sources.
This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 101004719.