[vsnet-grb-info 13033] GRB130408A: Swift/UVOT followup observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14370
SUBJECT: GRB130408A: Swift/UVOT followup observations
DATE:    13/04/09 11:07:36 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld at ucl.ac.uk>

A. Breeveld (MSSL/UCL) and A. Y. Lien (NASA/GSFC/ORAU) report on behalf 
of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130408A 
134 s after the BAT trigger (Lien et al., GCN Circ. 14361). A bright but 
rapidly fading source is detected in the initial exposures (Siegel and 
Lien, GCN Circ. 14363) with a position consistent with detections by 
Melandri et al., (GCN Circ., 14362), Sudilovsky et al., (GCN Circ., 
14364) and Beardmore et al., (GCN Circ. 14367).

The preliminary UVOT position is:
  RA(J2000)  =    08:57:37.30 = 134.40540
  DEC(J2000) =   -32:21:38.9  = -32.36081
with a 90%-confidence error radius of about 0.5 arc sec.

Preliminary detections and 3-sigma upper limits using the UVOT 
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for 
the early and summed exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              156          305      147.4          16.80 ± 0.05
white             3708         3900      189.2          20.29 ± 0.22
white             6083        10367      924.3          21.99 ± 0.35
v                  134          145       10.1          15.75 ± 0.15
v                 4201         4400      196.7          19.61 ± 0.35
b                 3503         6078      393.2          >20.84
u                  313         5872      236.2          >20.55
uvw1              4611         4752      139.0          >19.82
uvm2              4405         4605      196.6          >19.75
uvw2              3996        21851     1748.0          >21.56

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.258 in the direction of 
the burst (Schlegel et al. 1998).