The Swift/UVOT began settled observations of the field of GRB 100905A 77s after the BAT trigger (Marshall et al., GCN 11214). Data summed from the first and second orbits do not reveal a source at the enhanced position of the X-ray afterglow (Evans et al., GCN 11219). The 3-sigma upper limits for the finding chart (fc) and summed exposures are reported below: FILTER T_start(s) T_stop ...Full Text

We obtained further observations at multiple epochs of the afterglow of GRB 100901A (Immler et al., GCN 11159) with the TLS 1.34m Schmidt telescope. After another completely overcast night, we obtained data under good to excellent conditions in the third and fourth nights. For our first epoch (Kann et al., GCN 11187) we had used 5 USNO B1.0 R2 stars. Now, we compare their magnitudes with those...Full Text

K.Ivanov, O.Chuvalaev, V.Poleschuk, E.Konstantinov, V.Lenok, O.Gres, S.Yazev, N.M.Budnev, Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory Observations...Full Text

We continue observation of the Swift GRB 100814A (Immler et al. GCN 11159) with 0.45-m telescope of ISON-NM observatory on Sep. 04 (UT) 09:04:35 - 10:06:19, Sep. 05 (UT) 08:45:52 - 09:50:20 and Sep. 06 (UT) 09:36:57 - 11:14:22. The afterglow (Immler et al., GCN 11159; Guidorzi et al., GCN 11160; Ivanov et al., GCN 11161; Klunko et al., GCN 11162) is well detected on stacked images for three...Full Text

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GCN 11227) with a series of z, Y, J, H, and K filters using UKIRT. The observation started at Sept. 06, 14:23 UT or roughly 34 minutes after the BAT alert. We clearly identify an uncatalogued source in images in all the filters. The preliminary magnitude of the afterglow is J= 14.93 +- 0.02 and K=13.54 +- 0.02 (Vega), calibrated against 2MASS stars in the vicinity. ...Full Text

K.Ivanov, O.Chuvalaev, V.Poleschuk, E.Konstantinov, V.Lenok, O.Gres, S.Yazev, N.M.Budnev, Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory...Full Text

We observed the location of GRB 100906A (Markwardt et al. GCN 11227; Ivanov et al. GCN 11228; Melandri et al. GCN 11229) with the Gemini-North Telescope on Mauna Kea using the GMOS spectrograph. Observations began at 14:30 UT, approximately 40 minutes post burst. We detect strong continuum from the afterglow, and identify numerous absorption lines, including CIV (1458, 1551A), FeII (2344, 2374...Full Text

The Faulkes Telescope North automatically began observing Swift GRB 100906A (trigger = 433509, Markwardt et al., GCN 11227) on September 06,13:53:03 UT, about 3.5 minutes from the GRB trigger time. We clearly identify an uncatalogued object at the following position: RA(J2000.0): 01:54:44.09 Dec(J2000.0): +55:37:49.5 The position is consistent with UVOT candidate and the object is clearly fading...Full Text

E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M. Kornilov Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational...Full Text

At 13:49:27 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 100906A (trigger=433509). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 28.709, +55.614, which is RA(J2000) = 01h 54m 50s Dec(J2000) = +55d 36' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows...Full Text

A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok, O.Gres, O.Chuvalaev, V.Poleschuk Irkutsk State University As...Full Text

We observed the field of GRB 100905A (Marshall et al., GCN 11214) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. The observation started on 2010-09-05 18:56:36 UT (~0.16 day after the burst). We did not find any new point source within the enhanced XRT error circle (Evans et al., GCN 11219) in all the...Full Text

We observed the field of GRB 100905A (Marshall et al., GCN 11214) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2010-09-05 15:31:18 UT (~23 min after the burst). We did not find any new point source within the enhanced XRT error circle (Evans et al., GCN 11219) in all the three bands...Full Text

We have analysed 7.1 ks of XRT data for GRB 100905A (Marshall et al. GCN 11214), from 78 s to 13.6 ks after the BAT trigger. The data comprise 71 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN. Circ 11219). The light curve shows some initial flaring activity, with the flares peaking at around...Full Text

GCN 11214) in z, J, H, and K filters using UKIRT. The observation started at Sept. 05, 15:22 UT or roughly 17 minutes after the BAT alert, until the sunrise. The reduced images with non-optimal calibration frames show a "possible" very faint source within the XRT error circle (Evans et al. GCN 11219) whose significance is only 2-3 sigma in each image (2-sigma limit, J=19.8, H=19.0...Full Text

"We observed the position of the GRB 100901A afterglow at 4.9 GHz with the Westerbork Synthesis Radio Telescope at September 3 20.35 UT to September 4 08.50 UT, i.e. 2.29 - 2.79 days after the burst (GCN 11159). We detect a radio source at the position of the X-ray and UV/optical counterpart (GCN 11195) at the 4-sigma level, with a flux density of 134 +/- 33 microJy. We would like to thank the...Full Text

"We have observed the field of GRB 100905A (Marshall et al. GCN 11214) using the 1.5m telescope of the Observatorio de Sierra Nevada, in Granada (Spain). In a 7x300s combined I-band frame, with mean epoch September 5.9792 UT (8.36 hours after the burst onset), we do not detect any new source within the enhanced XRT position (Evans et al. GCN 11219) down to a 3-sigma limiting magnitude of 22.8....Full Text

Using 1956 s of XRT Photon Counting mode data and 2 UVOT images for GRB 100905A, 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 = 31.55023, +14.92941 which is equivalent to: RA (J2000): 02h 06m 12.06s Dec (J2000): +14d 55' 45.9" with an uncertainty of 1.6 arcsec (radius, 90% confidence). This...Full Text

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