We report on further analysis of the GROND data of the optical afterglow candidate of GRB 081228 (Swift trigger 338338, Page et al., GCN 8742). The optical/NIR source inside the XRT errorcircle, previously reported in GCN 8745 by P. Afonso et al., is found to be clearly variable. The position of the afterglow is: RA(J2000): 02:37:50.94 DEC(J2000): +30:51:10.5 with uncertainties of 0.5" in...Full Text

Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of Swift GRB 081228 (trigger #338338) (Page, et al., GCN 8742). The BAT ground-calculated position is RA, Dec = 39.477, 30.833 deg which is RA(J2000) = 02h 37m 54.4s Dec(J2000) = +30d 49' 57.3" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding...Full Text

The Swift/UVOT began settled observations of the field of GRB 081228 82s after the BAT trigger (Page et al., GCN 8742). The exposure time was limited by observing constraints until about 1 hour after the trigger. We do not detect any source at the refined Swift XRT position (Page & Evans GCN 8746). UVOT magnitude 3-sigma upper limits in a 5" aperture are reported in the following table...Full Text

We have analysed the first 4.6 ks of XRT data obtained for GRB 081228 (Page et al., GCN 8742), all of which was collected in Photon Counting mode. We have further refined the position given by Goad et al. in GCN 8744, and now find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) of RA (J2000): 02 37 50.89 Dec...Full Text

P. Afonso (MPE), S. Klose (Tautenburg), T. Kruehler, (MPE), J. Greiner (MPE), A. Updike (Clemson University), A. Kupcu-Yoldas(ESO), A. Yoldas (MPE), and G. Szokoly (Eötvös Univ. Budapest) report on behalf of the GROND team: GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile) imaged the field of GRB 081228 (Swift trigger 338338...Full Text

Using 27 s of XRT Photon Counting mode data and 1 UVOT images for GRB 081228, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 39.4616, +30.8526 which is equivalent to: RA (J2000): 02h 37m 50.77s Dec (J2000): +30d 51' 09.5" with an uncertainty of 2.9 arcsec (radius, 90% confidence). This position...Full Text

We imaged the field of GRB 081228 detected by SWIFT (trigger 338338) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 24.7s after the GRB trigger (6.1s after the notice). The elevation of the field decreased from 24 degrees above horizon and weather conditions were good. The first image is trailed with a duration of 60.0s (see the description...Full Text

At 01:17:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 081228 (trigger=338338). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 39.467, +30.843 which is RA(J2000) = 02h 37m 52s Dec(J2000) = +30d 50' 33" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed...Full Text