GCN Circular 39912
Subject
GRB 250327B: LCO optical counterpart detection
Date
2025-03-28T18:04:55Z (22 days ago)
From
Ismael Perez-Fournon at Instituto de Astrofisica de Canarias <ipf@iac.es>
Via
Web form
I. Pérez-Fournon, F. Poidevin (IAC and ULL), D. Cano-Morales, I. Correa-Plasencia, A.E. Hernández-Díaz (ULL), and A. López-Oramas (IAC and ULL)
We report Las Cumbres Observatory Global Telescope network (LCOGT) observations of GRB 250327B, detected by SVOM ECLAIRs and MXT (Bouchet et al., GCN circ. 39888) and VT (Xin et al., GCN circ. 39890) and Swift XRT (Page et al., GCN circ. 39895) at a redshift of z = 3.035 (Malesani et. al, GCN circ. 39893; Dennefeld et al., GCN circ. 39905).
We observed the field of GRB 250327B with the two LCOGT 1-m telescopes, equipped with Sinistro cameras, located at the LCOGT node at Teide Observatory (Tenerife, Spain) in the SDSS r, g, and i filters, starting at 2025-03-27 23:55:43 UT, about 2.74 hours after the SVOM trigger. An uncatalogued source is clearly detected at the position of the optical counterpart reported by Moskvitin et al., GCN circ. 39889; Xin et al., GCN circ. 39890; O’Neill et al., GCN circ. 39891; Malesani et al., GCN circ. 39893; Lian et al., GCN circ. 39894; Shrestha et al., GCN circ. 39896; Ducoin et al., GCN circ. 39897; Perley and Bochenek, GCN circ. 39902; Kumar et al., GCN circ. 39904; Dennefeld et al., GCN circ. 39905; and Pankov et al., GCN circ. 39906).
We measure the following magnitudes, calibrated against Pan-STARRS DR2 stars and not corrected for Galactic extinction:
Date | UT start | mag | error | filter | exposure time (sec)
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2025-03-27 23:55:43 18.24 0.02 r 180
2025-03-28 00:31:11 20.07 0.06 g 180
2025-03-28 00:34:41 18.19 0.04 i 180
2025-03-28 02:12:57 18.79 0.06 i 180
2025-03-28 03:04:23 19.35 0.05 r 300
2025-03-28 03:09:13 21.25 0.14 g 180
This work makes use of observations from the Las Cumbres Observatory global telescope network (LCOGT observing programme IAC2025A-009, SGLF).