[vsnet-grb-info 10628] GRB 110530A: Swift/UVOT Detection of a Fading Afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12057
SUBJECT: GRB 110530A: Swift/UVOT Detection of a Fading Afterglow
DATE:    11/05/31 14:14:04 GMT
FROM:    Frank Marshall at GSFC  <femarsha at khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) 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 110530A
438 s after the BAT trigger (D'Avanzo et al., GCN Circ. 12046).
A fading source consistent with the enhanced XRT position
(Evans et al., GCN Circ. 12055) is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  18:48:16.40 = 282.06833 (deg.)
    Dec (J2000) = +61:55:44.9  =  61.92913 (deg.)
with an estimated uncertainty of 0.65 arc sec. (radius, 90% confidence).

Preliminary detections using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the early exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag
white              438         1015          295         20.31 +/- 0.10
white             7070         8315         1042         21.52 +/- 0.21

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).