GCN Circular 35458
Subject
GRB 240101B: Swift/UVOT Upper Limits
Date
2024-01-02T12:11:38Z (a year ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
Via
email
N. P. M. Kuin (UCL-MSSL) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240101B
110 s after the BAT trigger (Cenko et al., GCN Circ. 35449).
No optical afterglow consistent with the XRT position
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 134 284 147 >21.1
u_FC 294 543 246 >20.1
white 134 1718 411 >21.8
v 110 1595 130 >19.2
b 549 1693 117 >20.5
u 294 1669 343 >20.2
w1 675 1644 117 >19.3
m2 648 1619 97 >21.0
w2 599 1741 134 >19.3
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.287 in the direction of the burst
(Schlegel et al. 1998).