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).

View this GCN Circular online at https://gcn.nasa.gov/circulars/43016. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...