TITLE:   GCN CIRCULAR
NUMBER:  43016
SUBJECT: GRB 251205A: Swift/UVOT Detection
DATE:    25/12/06 18:47:19 GMT
FROM:    N. Klingler at NASA-GSFC/UMBC/CRESST II <noelklingler@gmail.com>

N. Klingler (NASA-GSFC / UMBC / CRESST II) and Sophia Lanava (PSU) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 251205A 149 s after the BAT trigger (Lanava et al., GCN Circ. 43005). A source consistent with the XRT position (RA, Dec = 13h 21m 05.26s, +29d 55' 44.2"; Beardmore et al., GCN Circ. 43007) is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  13:21:05.34 = 200.27223 (deg.)
    Dec (J2000) = +29:55:44.0  =  29.92890 (deg.)
with an estimated uncertainty of 0.43 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)    Mag

white      148.9     298.7     17.61 +/- 0.06      
white      586.8     606.5     16.96 +/- 0.09      
white      759.1     869.1     16.89 +/- 0.08      
white    16513.5   17308.6     17.77 +/- 0.05      

b          562.4     582.2     17.32 +/- 0.17      
b          734.9     754.7     17.29 +/- 0.18      
b        15601.3   16508.4     18.18 +/- 0.05      

u          306.8     556.6     16.65 +/- 0.06      
u          710.3     730.0     16.57 +/- 0.16      
u        22323.1   22838.7     17.51 +/- 0.06      

v          636.4     656.2     17.10 +/- 0.27      
v          808.6     828.4     16.92 +/- 0.24      
v        10660.9   11393.6     18.45 +/- 0.10      

uvw1       685.8     705.5     16.18 +/- 0.18      
uvw1     21416.9   22316.6     17.83 +/- 0.07      

uvw2      9754.6   10654.4     18.44 +/- 0.10      

The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.014 in the direction of the burst (Schlegel et al. 1998).