[vsnet-grb-info 11747] GRB 120327A: Swift/UVOT further analysis
GCN Circulars
gcncirc at capella2.gsfc.nasa.gov
Tue Mar 27 21:52:37 JST 2012
TITLE: GCN CIRCULAR
NUMBER: 13138
SUBJECT: GRB 120327A: Swift/UVOT further analysis
DATE: 12/03/27 12:50:38 GMT
FROM: Paul Kuin at MSSL <npkuin at gmail.com>
N. P. M. Kuin (MSSL-UCL) and B. Sbarufatti (INAF-OAB/PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120327A
141 s after the BAT trigger (Sbarufatti et al., GCN Circ. 13123).
A source consistent with the enhanced XRT position (Osborne et al.
GCN Circ. 13135) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 16:27:27.48 = 246.864500 (deg.)
Dec (J2000) = -29:24:53.74 = -29.414928 (deg.)
with an estimated uncertainty of 0.48 arc sec. (radius, 90% confidence).
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
v 448 468 20 15.68 +/- 0.10
b 396 416 20 16.97 +/- 0.11
u 141 391 246 18.02 +/- 0.08
w1 497 1295 97 >19.0
m2 622 1271 78 >19.2
w2 424 1222 97 >19.6
The absence of detection in uvw1, uvm2, and uvw2 is consistent with the
reported redshift of 2.81 (Perley & Tanvir, GCN Circ 13133, and
Krueler et al, GCN Circ. 13134).
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.34 in the direction of the burst
(Schlegel et al. 1998).
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