The Swift/UVOT observed the field of GRB 100727A starting 47 s after the BAT trigger (Morris, et al., 2010, GCN 10998). Settled observations started at 65 s. We do not find any new source, relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT afterglow (Osborne, et al. 2010, GCN 11000). Preliminary 3-sigma upper limits for detecting a source in the finding charts, and in the co-added...Full Text

We have analysed 9.8 ks of XRT data for GRB 100727A (Morris et al. GCN 10998), from 48 s to 39.8 ks after the BAT trigger. The data comprise 185 s in Windowed Timing (WT) mode (the first 7 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 11000). The light curve can be modeled with...Full Text

"At 05:42:22.00 UT on 27 July 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100727A (trigger 301902143 / 100727238), which was also detected by the SWIFT-BAT (Morris et al. 2010, GCN 10998) The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 95.1 degrees. The GBM light curve consists of single peak with a duration (T90)...Full Text

Using the data set from T-240 to T+617 sec from the recent telemetry downlink, we report further analysis of BAT GRB 100727A (trigger #430094) (Morris, et al., GCN 10998). The BAT ground-calculated position is RA, Dec = 154.187, -21.417 deg which is RA(J2000) = 10h 16m 44.8s Dec(J2000) = -21d 25' 02.7" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial...Full Text

Using 4198 s of XRT Photon Counting mode data and 8 UVOT images for GRB 100727A, 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 = 154.17739, -21.39042 which is equivalent to: RA (J2000): 10h 16m 42.57s Dec (J2000): -21d 23' 25.5" with an uncertainty of 1.6 arcsec (radius, 90% confidence). This...Full Text

We searched for an optical afterglow of GRB 100727A (GCN 10998, D. C. Morris et al.) starting from 07:12:3 UT on 2010 July 27 ( 90 minutes after the burst) with the MOA-II 1.8m telescope at Mt.John observatory in New Zealand. In a single image of a 300 sec exposure with a wideband Red filter (center wavelength ~ 750nm and FWHM ~ 250nm), we did not find any object within the error circle of the...Full Text

At 05:42:17 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 100727A (trigger=430094). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 154.166, -21.364 which is RA(J2000) = 10h 16m 40s Dec(J2000) = -21d 21' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed...Full Text