GCN Circular 17139
F. E. Marshall (NASA/GSFC) and S. B. Cenko (NASA/GSFC) report on behalf of the Swift/UVOT team: The short/hard GRB 141202A was localized to a 1439 sq. arcmin error box with the IPN (Golenetskii et al. GCN Circ. 17131), and Swift tiled the error box with 7 fields starting 93.5 ks after the trigger. No credible afterglow was detected with the Swift/XRT (Pagani et al. GCN Circ. 17134). In two exposures with the U filter starting 128 ks after the trigger, Swift/UVOT finds a bright source just outside the IPN error region that is not seen in the DSS or the SDSS. In addition, no source at this position was found with the Minor Planet Checker. There is a dim SDSS galaxy with a g' magnitude (AB) of 23.0 +/- 0.2 coincident with the UVOT source. A 3-sigma upper limit for this galaxy in the u' band is 22.4 mag. The preliminary UVOT position is: RA (J2000) = 09:32:29.78 = 143.12408 (deg.) Dec (J2000) = 55:19:44.4 = 55.32899 (deg.) with an estimated uncertainty of 0.5 arcsec. (radius, 90% confidence). There is very marginal evidence (1.8-sigma) for variability between the two UVOT observations. The preliminary AB magnitudes using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) is: Filter T_start(ks) T_stop(ks) Exp(ks) Mag (AB) u 127.9 128.6 0.69 20.43 +/- 0.09 u 129.4 130.3 0.88 20.69 +/- 0.13 No correction is made for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the source (Schlegel et al. 1998). The 3-sigma upper limit for the XRT count rate at the position of the UVOT source is 9.6e-3 counts/s in the 0.3-10 keV band. It would be very unusual for UVOT to find a bright optical afterglow for a short/hard GRB so long after the trigger, especially since XRT did not find an afterglow. The long-term increase in the optical flux by a factor of at least 6 indicates that this may nevertheless be an interesting object.