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GCN Circular 39896

Subject

GRB 250327B: Las Cumbres optical counterpart detection

Date

2025-03-28T04:43:23Z (5 days ago)

From

Manisha Shrestha at University of Arizona <mshrestha1@arizona.edu>

Via

Web form

M. Shrestha (Univ. of Arizona), D. Sand (Univ. of Arizona), K. D. Alexander (Univ. of Arizona), J. Andrews (Gemini), J. Pearson (Univ. of Arizona), N. Smith (Univ. of Arizona), K. Bostroem (Univ. of Arizona), C. Christy (Univ. of Arizona), N. Franz (Univ. of Arizona), D. A. Howell (LCO/UCSB), C. McCully (LCO/UCSB), M. Newsome (LCO/UCSB), J. Farah (LCO/UCSB) report on behalf of a wider Global Supernova Project collaboration:

We observed the field of GRB 250327B (SVOM team, GCN 39888

) with the 1-m telescope, starting on 025-03-28T02:38:50.16 UT (60762.11 MJD, ~5.5 hours after the trigger) using the Sinistro instrument in g, r, i bands (exposure of 2×200 s). We clearly detect the optical counterpart as reported in previous circulars ( Moskvitin+ GCN , Xin+ GCN , O’Neill+ GCN , Malesani+ GCN , Lian+ GCN ). Preliminary photometric data are as follows:

g = 20.7 +-0.1 r = 19.4 +-0.1 i = 18.8 +- 0.1

These values were calculated with respect to ATLAS-REFCAT2 (Tonry et al. 2018, ApJ 867 105) catalog. They are not corrected for galactic extinction. This source is fading compared to the magnitude reported in Malesani+ GCN 39893