[vsnet-grb-info 14949] GRB 140508A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16243
SUBJECT: GRB 140508A: Swift/UVOT Detection
DATE:    14/05/09 19:03:14 GMT
FROM:    Frank Marshall at GSFC  <femarsha at khamseen.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and A. Amarel-Rogers (U. of Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140508A
68965 s after the GBM trigger (Yu and Goldstein, GCN Circ. 16224).
A source consistent with the optical position
(Singer et al., GCN Circ. 16226) and the X-ray position
(Amarel-Rogers, GCN Circ. 16232)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  17:01:51.95 = 255.46647 (deg.)
    Dec (J2000) = +46:46:49.5  =  46.78043 (deg.)
with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence).

Preliminary detections 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                68965        69792          814         19.38 +/- 0.10
b                70632        71427          782         19.59 +/- 0.06
u                69799        70626          814         18.81 +/- 0.05

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.031 in the direction of the burst
(Schlegel et al. 1998).