GCN Circular 18698
Subject
GRB151215A: Swift/UVOT detection
Event
Date
2015-12-15T16:28:33Z (10 years ago)
From
Massimiliano de Pasquale at IASF-Palermo <m.depasquale@ucl.ac.uk>
M. De Pasquale (UCL-MSSL) and S. L. Gibson (U Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 151215A
174 s after the BAT trigger (Gibson et al., GCN Circ. 18691).
We detect the optical afterglow of GRB151215A within the XRT error
circle (Evans et al. GCN Circ. 18695), in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 06:14:20.25 = 93.58438 (deg.)
Dec (J2000) = +35:30:57.4 = 35.51595 (deg.)
with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence).
The position of this source is consistent with those given by Cenko et al.
(GCN Circ. 18692) and GROND (Wiseman et al. GCN Circ. 18694).
There is no detection in UVOT uv filters, which is congruous with
the redshift z=2.6 of the event (Xu et al., GCN circ. 18696).
Preliminary detections and 3-sigma upper limits using the UVOT
photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early
exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (Finding Chart) 174 323 147 19.05 �� 0.14
white 531 2586 362 20.59 �� 0.19
v 408 2636 253 19.67 �� 0.35
b 507 2561 233 20.85 �� 0.42
u 482 2536 233 >20.3
w1 458 2512 233 >19.9
m2 433 2651 225 >19.6
w2 384 2612 253 >19.9
The magnitudes in the table are not corrected for the substantial Galactic
extinction due to the reddening of E(B-V) = 0.39 in the direction of the
burst
(Schlegel et al. 1998).
--
Dr. Massimiliano De Pasquale
Research associate - Swift UVOT scientist
Mullard Space Science Laboratory, University College London