TITLE: GCN CIRCULAR NUMBER: 16241 SUBJECT: GRB 140509A: Swift/UVOT Detection and photo-z DATE: 14/05/09 17:42:38 GMT FROM: Frank Marshall at GSFC F. E. Marshall (NASA/GSFC) and K. L. Page (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140509A 121 s after the BAT trigger (Page et al., GCN Circ. 16230). A source consistent with the XRT position (Beardmore et al. GCN Circ. 16233) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 03:06:22.69 = 46.59456 (deg.) Dec (J2000) = -62:38:21.7 = -62.63935 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits 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 white 121 271 147 17.00 +/- 0.03 v 610 630 20 16.50 +/- 0.13 b 536 556 20 17.04 +/- 0.10 u 280 530 246 16.35 +/- 0.03 w1 659 7011 490 >20.6 m2 634 6806 490 >21.1 w2 585 6396 432 >20.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). The lack of detections in the UV filters suggests a redshift of about 2.4.