GCN Circular 39385
Subject
GRB 250219A: Swift/UVOT Upper Limits
Event
Date
2025-02-20T10:56:47Z (10 months ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
Via
email
A.A. Breeveld (UCL-MSSL) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of the SVOM/ECLAIRS-detected burst GRB 250219A (Daigne et al., GCN Circ. 39376) 5.1 ks after the trigger. The afterglow reported by Kennea et al. (GCN Circ. 39379), Xin et al. (GCN Circ. 39380), Magnani et al. (GCN Circ. 39382) and Fu et al. (GCN Circ. 39383) is not detected in the U-band exposures.
Preliminary 3-sigma upper limit using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial summed exposure is:
Filter T_start(s) T_stop(s) Exp(s) Mag
u 5097 11297 330 >20.1
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.016 in the direction of the burst (Schlegel et al. 1998).