[vsnet-grb-info 15957] GRB 141225A: Swift/UVOT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17242
SUBJECT: GRB 141225A: Swift/UVOT refined analysis
DATE:    14/12/26 18:37:57 GMT
FROM:    Paul Kuin at MSSL  <npkuin at gmail.com>

N. P. M. Kuin (UCL-MSSL) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 141225A
428 s after the BAT trigger (D'Avanzo et al., GCN Circ. 17229). The optical
afterglow has been reported (Gorosabel et al, GCN Circ. 17230; Guidorzi et
al.,
GCN Circ. 17231; Malesani et al., GCN Circ. 17232; Kuin & D'Avanzo,
GCN.Circ.
17233; Xu et al., GCN Circ. 17236; Buckley et al., 17237; Sonbas et al.,
GCB
Circ. 17240) with a redshift of z=0.915 (Gorosabel et al., GCN Circ. 17234).

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              428          578          147         18.81 +/- 0.06
white              858         1008          147         19.76 +/- 0.10
v                  735         1406           78        >19.2
b                  660         1495           86        >19.5
u                  636         1481           97         19.19 +/- 0.19
w1                 611         1456           97        >19.0
m2                 760          780           19        >18.6
w2                6480         6680          197        >19.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).