NOTE: This file contains both bursts 051117A and 051117B //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4280 SUBJECT: GRB 051117: Swift detection of a bright burst DATE: 05/11/17 11:44:49 GMT FROM: Scott Barthelmy at NASA/GSFC D. Band (GSFC), S. Barthelmy (GSFC), A. Beardmore (U Leicester), D. Burrows (PSU), N. Gehrels (GSFC), M. Goad (U. Leicester) O. Godet (U. Leicester), C. Gronwall (PSU), J. Kennea (PSU), K. Page (U Leicester), E. Rol (U. Leicester) on behalf of the Swift team: At 10:51:20 UT, Swift-BAT triggered and located GRB 051117 (trigger=164268). The spacecraft slewed immediately. The BAT on-board calculated location is RA,Dec 228.405d, +30.870d {+15h 13m 37s, +30d 52' 11"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve shows a single peak with a total duration of about 20 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~3 sec after the trigger. XRT began observing at 10:53:07 UT, 107 seconds after the BAT trigger. We find a bright, rapidly fading, uncataloged source at RA 15h 13m 33.7s Dec +30d 52' 22.0" (J2000) with a positional uncertainty of 5.8 arcsec (90% containment). This is 46 arcsec from the BAT position. The approximate initial flux is 1.0e-8 erg/cm2/sec (0.2-10 keV). The XRT preliminary raw spectrum is well fit by an absorbed powerlaw with a photon index of 2.2+/- 0.1 with an excess NH of 2e21 cm^-2. UVOT began observing at UT 10:53:10, 111 seconds after the BAT trigger. In a 200 sec V image, we detect a faint source just outside the XRT error circle at an approximate position of RA=15h 13m 33.6s, Dec=30d 52' 15.2" (J2000) that is not present in the DSS. The magnitude is 19.9 mag. The extinction in this direction is A_V = 0.08. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4281 SUBJECT: GRB 051117B: Swift detection of a burst DATE: 05/11/17 13:59:44 GMT FROM: Scott Barthelmy at NASA/GSFC D. Band (PSU), S. Barthelmy (GSFC), A. Beardmore (U Leicester), D. Burrows (PSU), J. Cummings (GSFC/NRC), S.T. Holland (GSFC/USRA), M. Goad (U. Leicester), O. Godet (U. Leicester), N. Gehrels (GSFC), C. Gronwall (PSU), J. Kennea (PSU), H. Krimm (GSFC/USRA), J. Osborne (U Leicester), K. Page (U Leicester) on behalf of the Swift team: At 13:22:54 UT, Swift-BAT triggered and located GRB 051117B (trigger=164279). The BAT on-board calculated location is RA,Dec 85.225d,-19.245d {05h 40m 54s,-19d 14' 41"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve shows a multi-peak structure with a total duration of ~25 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~2 seconds after the trigger. The spacecraft slewed immediately and the XRT began observing the GRB at 13:25:09 UT, 135 sec after the BAT trigger. The on-board detection algorithm did not centroid on a source due to insufficient counts, so no prompt X-ray position is available. However, the XRT prompt light curve and raw spectrum look like a faint GRB. More information will be available around 16:30 UT, after the next Malindi ground-station pass. UVOT took a finding chart exposure of 200 sec with the V filter starting 133 sec after the BAT trigger. No afterglow candidate has been found in the initial data products. The sub-image covers 19% of the BAT error circle. No afterglow candidate is found in the list of sources generated on-board, which covers 89% of the BAT error circle. The list of sources is typically complete to about 17th mag. No correction has been made for the expected visual extinction of about 0.19 magnitudes. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4282 SUBJECT: GRB051117B: Swift XRT position DATE: 05/11/17 16:27:04 GMT FROM: Andy Beardmore at U Leicester A. Beardmore, K. Page, M. Goad (U. Leicester), J Kennea (PSU) report on behalf of the Swift XRT team: We have analysed the first orbit of XRT data from GRB051117B (Band et al, GCN4281). We find a fading, uncatalogued source located at RA(J2000) = 05h 40m 43.0s DEC(J2000) = -19d 16' 26.2" with an estimated uncertainty of 3.9" (90% containment). This includes the latest XRT boresight correction and is 3.14' from the BAT on-board position. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4283 SUBJECT: GRB 051117B: ROTSE-III Optical Limits DATE: 05/11/17 16:55:47 GMT FROM: Wiphu Rujopakarn at U Michigan/ROTSE W. Rujopakarn (U Mich), H. Swan (U Mich), B. Schaefer (Louisiana State), F. Yuan (U Mich), T. Guver (U Istanbul), report on behalf of the ROTSE collaboration: ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB 051117B (Swift trigger 164279), producing images beginning 18 s after the GCN notice time. An automated response took the first image at 13:24:11.0 UT, 75.6 s after the burst, under windy conditions. These observations were affected by proximity to the full moon yielding shallow limiting magnitudes. We took 10 5-sec, and 140 20-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 13.9-16.3; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 13:24:12.0 13:24:17.0 5 14.2 76.6 N 13:24:12.0 13:27:07.8 175 15.8 76.6 Y //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4284 SUBJECT: GRB 051117B: Optical observations DATE: 05/11/17 17:23:53 GMT FROM: Derek Fox at PSU D.B. Fox (Penn State) and R.H. McNaught (RSAA/ANU, SSO) report on behalf of a larger colloboration: "We have observed the Swift localization region for GRB 051117B (Band et al., GCN 4281) with the 40-inch telescope at Siding Spring Observatory, in a series of unfiltered exposures beginning at 14:12 UT (49 minutes after the burst). A coadded exposure at mean epoch 14:16 UT reveals no source coincident with the XRT position (Beardmore et al., GCN 4282), nor any new sources within the BAT localization region by comparison to the DSS. We estimate our limiting magnitude for this image to be R=18.8 mag by comparison to the USNO-B1.0 catalog R-band magnitudes of nearby stars." [GCN_OPS_NOTE(17nov05): per author's request the author list was added.] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4285 SUBJECT: GRB 051117B: Lulin R and I band observation DATE: 05/11/17 18:18:52 GMT FROM: Yuji Urata at RIKEN GRB 051117B: Lulin R and I band observation Y.T. Chen, K.Y. Huang, W.H. Ip (NCU), Y. Urata(RIKEN), Y. Qiu (BAO), Y.Q. Lou (THCA) on behalf of EAFON report: " We started R and I band imaging observation for GRB 051117B (Band et al., GCN 4281) with Lulin 1-m telescope at 14:11 UT (48 minutes after the burst). The stacked I-band image made from 9 x 300 s exposure shows a very faint sources at RA=05:40:43.3 Dec=-19:16:26(edge of Swift/XRT error region; Beardmore et al. GCN4282). The brightness calibrated with USNO-B1.0 catalog is about I=20.6. We could not find this source in stacked R-band image made from 3 x 300 s exposure brighter than R < 20.8 (SN=3). Further observation and analysis are in progress." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4286 SUBJECT: GRB 051117B,optical observation DATE: 05/11/17 18:46:58 GMT FROM: Eri Sonoda at U of Miyazaki/Japan E.Sonoda,S.Maeno,M.Yamauchi (University of Miyazaki) "We have observed the field covering the error circle of GRB 051117B(GCN4281;Swift-BAT Trigger time is 13:22:54 UT) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 14:03:16 on Nov.17. After co-adding a set of 7 images (14:03:16 - 14:10:31 UT) of 30 sec exposures, we have compared with the USNO A2.0 catalog. Preliminary analysis shows there is no new source brighter than 17.6 mag. in the XRT error region is reported by A.Beardmore et al.(GCN4282)." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4287 SUBJECT: GRB051117A : XRT refined analysis DATE: 05/11/17 19:32:08 GMT FROM: Michael Goad at U Leicester M. Goad, K. Page, D. Burrows (PSU), K. Hurley, (Berkeley), M. Chester (PSU) report on behalf of the Swift XRT team. From analysis of 2.3 ks of Photon Counting mode data of GRB051117A (Band et al., GCN 4280) we obtain a refined XRT position of RA: 15h 13m 33.8s, Dec:+30d 52m 13.3s (J2000) with an uncertainty of 3.4 arcsec (90% containment). This includes the latest XRT boresight correction. This refined position is 41 arcsec from the BAT on-board position and 3.4 arcsec from the UVOT position quoted in GCN 4280. We have also analysed 1.77 ks of XRT Windowed Timing mode observations starting 113 s after the BAT trigger. The XRT lightcurve displays multiple flares with a peak count rate of approximately 180 ct/s occurring 134 s after the BAT trigger. The early underlying decay slope of the XRT lightcurve is a powerlaw with slope ~1.1+/-0.1. The XRT WT mode 0.2-10 keV spectrum is well represented by an absorbed powerlaw with photon index 2.23+/-0.02 with a mean unabsorbed flux of 2.6E-09 ergs/cm2/s (between 113 s and 5.2 ks after the burst). We find evidence for excess NH above the Galactic value of 2.0e21 cm^-2. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4288 SUBJECT: GRB 051117B: Refined analysis of the Swift-BAT burst DATE: 05/11/17 20:41:10 GMT FROM: Scott Barthelmy at NASA/GSFC A. Parsons (GSFC), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), K. Hurley (Berkeley), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), J. Norris (GSFC), D. Palmer (LANL), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the full data set from the recent telemetry downlink, we report further analysis of Swift-BAT GRB 051117B (trigger #164279) (Band, et al., GCN 4281). The ground-analysis position is RA,Dec 85.187,-19.280 {05h 40m 44.9s,-19d 16' 48.5"} (J2000) with an uncertainty of 2.5 arcmin (radius, 90%, stat+sys). T90 is 8 +- 1 sec. The partial coding fraction is 73%. The lightcurve has a bump of ~10 sec in duration with a peak at T+1 sec. Fitting a simple power law over the full interval from T-0.3 to T+7.5 sec, the photon index is 1.7 +/- 0.3 with a fluence of 1.4 +/- 0.3 X 10^-7 erg/cm^2. The peak flux in a 1-sec wide window starting at T+1.4 sec is 0.46 +/- 0.15 ph/cm^2/sec. All values are in the 15-150 keV band at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4289 SUBJECT: GRB 051117A: Refined analysis of the Swift-BAT burst DATE: 05/11/17 21:52:20 GMT FROM: Scott Barthelmy at NASA/GSFC D. Palmer (LANL), L. Barbier (GSFC), S. Barthelmy (GSFC), L. Cominsky (Sonoma State U.), J. Cannizzo (GSFC-UMBC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the full data set from the recent telemetry downlink, we report further analysis of Swift-BAT GRB 051117A (trigger #164268) (Band, et al., GCN 4280). The ground-analysis position is RA,Dec 228.399,+30.870 {15h 13m 35.7s,+30d 51' 10.3"} (J2000) with an uncertainty of 1.0 arcmin (radius, 90%, stat+sys). T90 is at least 140 +- 10 sec. The partial coding fraction is 72%. The lightcurve has a long FRED-like peak at T-15 sec lasting out to at least T+190 sec. There is a hint of emission peaks at T+225 and T+350 (each ~30 sec in duration). Fitting a simple power law over the interval from T-29 to T+157 sec, the photon index is 1.83 +/- 0.07 with a fluence of at least 4.6 +/- 0.16 X 10^-6 erg/cm^2. The peak flux in a 1-sec wide window starting at T+2.47 sec is 0.93 +/- 0.17 ph/cm^2/sec. All values are in the 15-150 keV band at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4290 SUBJECT: GRB 051117b: NIR observations DATE: 05/11/18 06:55:34 GMT FROM: Edo Berger at Carnegie Obs E. Berger (Carnegie Observatories) and A. Scholz (U. of Toronto) report: "We observed the position of GRB 051117b (GCN 4281) with WIRC on the du Pont 100-inch telescope at Las Campanas Observatory starting on 2005 Nov 18.10 UT. A total of 30 min were obtained in the Ks band. No sources are detected within the XRT error circle (GCN 4282) to a 3-sigma limit of Ks>19.3 mag in comparison to two nearby 2MASS stars. A single extended source, which is also visible in the DSS, is detected about 0.8" from the eastern edge of the error circle with Ks=17.9 mag." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4291 SUBJECT: GRB 051117B: R and I observations of possible host galaxy DATE: 05/11/18 13:19:34 GMT FROM: Christina Thoene at Niels Bohr Institute,DARK Cosmo Ctr C. Thoene and C. Feron, P. Jakobsson, B.L. Jensen, J.P.U. Fynbo, J. Sollerman, H. Pedersen, D. Watson, J. Hjorth (DARK Cosmology Centre, NBI) report: We observed the field of GRB 051117B (Band et al. GCN 4281) with DFOSC at the Danish 1.54m telescope on La Silla from 18 Nov 2005 starting at 02:58 UT. Exposures of 8 x 600s in R and 18 x 600s in Gunn-i were obtained with a seeing of 1.5". We detect an extended source lying on the edge of the XRT error circle (Beardmore et al. GCN 4282) in both bands as found by Chen et al. in R (GCN 4285). The source is centered at: (RA,Dec)(J2000.0) = (05:40:43.26,-19:16:26.1). No other sources are detected in or near the XRT-circle, nor were there any appreciable brightness variations in the extended source during our observations. Using preliminary photometric zeropoints we estimate the following magnitudes for this source: 21.0 in R and 20.4 in Gunn-i and a color index of R-I=0.6. We estimate the probability to find a similar galaxy by chance in the error-circle to be 5% (based on Postman et al. ApJ 506, 33 (1998)). If the extended source is the host galaxy associated with GRB 051117B, this would be one of the brightest host galaxies of long-duration Swift GRBs. A finding chart of the field is available at: http://www.astro.ku.dk/~brian_j/grb/grb051117.558/ //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4292 SUBJECT: GRB 051117A and B: Radio Observations DATE: 05/11/18 13:26:37 GMT FROM: Dale A. Frail at NRAO Dale A. Frail (NRAO) reports on behalf of a larger collaboration: "We observed both recent bursts, GRB 051117A (GCN 4280) and GRB 051117B (GCN 4281) with the Very Large Array at 8.5 GHz centered on November 18.51 UT and 18.48, respectively. Within the XRT error circles (GCN 4282; GCN 4287) we no radio emission above 3-sigma, for an rms noise of 56 uJy (GRB 051117A), and 40 uJy (GRB 051117B). No further observations are planned. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4293 SUBJECT: GRB 051117B: MARGE Optical Limits DATE: 05/11/18 23:56:16 GMT FROM: Heather Swan at U.of Michigan/ROTSE H. Swan (U Mich), W. Rujopakarn (U Mich), and I. Smith (Rice) report on behalf of the MARGE collaboration: The AEOS Burst Camera (ABC) on the AEOS telescope, located at the Maui Space Surveillance System on Haleakala, responded to GRB051117B (Swift trigger 164279). Images with a low resolution diffraction grating were taken between 13:40 and 13:54 UT, under scattered cloud conditions. The first image was taken 14 minutes after the GCN notice time, and the exposure time was 10 seconds for each image. A preliminary analysis gives a limiting magnitude of 19.4 at 13:48 UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4300 SUBJECT: GRB 051117A: Swift/UVOT Detection of an Afterglow DATE: 05/11/22 19:02:07 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC GRB 051117A: Swift/UVOT Detection of an Afterglow S. T. Holland (GSFC/USRA), D. Band (GSFC), K. Mason (PPARC), F. Marshall (GSFC), & N. Gehrels (GSFC) on behalf of the Swift/UVOT team report: The Swift/UVOT began observing the field of GRB 051117A (BAT Trigger 163268; Band et al. 2005, GCN Circular 4280) at 2005-11-17T10:53:10, 111 seconds after the burst. We detect a fading source corresponding to the UVOT source in Band et al. (2005, GCN Circular 4280). The refined coordinates of this source are: RA(J2000) = 15:13:39.09 Dec(J2000) = +30:52:12.7 with a positional uncertainty of +/-0.5 arcsec (1-sigma). The transient has V = 20.01 +/- 0.46 (1-sigma, statistical) in a 200 s exposure starting at 110 seconds after the BAT trigger. This value supersedes the approximate magnitude given in Band, et al. (2005, GCN Circular 4280). This magnitude has not been corrected for Galactic extinction. The magnitude in the UVOT White filter is 19.19 +/- 0.16 (1-sigma, statistical) in a 50 s, exposure starting 531 s after the BAT trigger. The source has faded to a White magnitude of approximately 21.5 by 3.5 days after the burst. There is weak evidence that the source is extended, so this may represent the luminosity of the host galaxy of GRB 051117A. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4301 SUBJECT: GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction DATE: 05/11/22 21:11:22 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction S. T. Holland (GSFC/USRA), on behalf of the Swift/UVOT team report: There is an error in the coordinates for the UVOT fading source associated with GRB 051117A (Holland et al., 2005, GCN Circular 4300). The correct coordinates are RA(J2000) = 15:13:34.09 Dec(J2000) = +30:52:12.7 with a positional uncertainty of +/-0.5 arcsec (1-sigma). We apologize for this error and any inconvenience that it may have caused. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4303 SUBJECT: GRB051117b: No Swift/UVOT Detection DATE: 05/11/24 15:11:02 GMT FROM: Tracey Poole at MSSL T. S. Poole (UCL-MSSL), S. T. Holland (GSFC), D. Band (GSFC), P. Boyd (GSFC-UMBC) & J. Nousek (PSU) on behalf of the Swift/UVOT team report: The Swift-Ultra-Violet/Optical Telescope (UVOT) began observing the field of GRB 051117b (BAT Trigger=164279; Band et. al. GCN 4281) at 2005-11-17 13:22:54 UT, 133 seconds after the burst. No new source is detected within the 4 arcsec radius XRT error circle at position RA=5h 40m 43s, Dec=-19d 16' 26.2" (Beardmore et. al. GCN 4282) in any of the UVOT filters down to the following co-added 5 sigma magnitude upper limits: Filter T_range (sec) Exp (sec) 5-sigma V 133-24975 5236 20.53 B 499-1608 199 19.59 U 445-7019 311 19.66 UVW1 391-366901 1099 21.00 UVM2 277-5993 1110 21.08 UVW2 608-1713 2340 23.24 WHITE 553-982 100 19.49 Where T_range is time post-trigger, and T_exp is the exposure time of the observation. A 6 arcsec aperture was used for all filters. These values are not corrected for Galactic extinction. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4304 SUBJECT: GRB051117B: Swift XRT refined analysis DATE: 05/11/25 16:39:23 GMT FROM: Andy Beardmore at U Leicester A.P. Beardmore, K.L. Page (U. Leicester), K. Hurley (Berkeley), M. Chester (PSU) report on behalf of the Swift XRT team. We report on further analysis of the XRT observation of GRB051117B. By fitting the XRT point spread function to 8ks of PC mode data obtained from the first observation segment, we find the following revised position: RA(J2000) = 05:40:43.0 Dec(J2000) = -19:16:26.5 with an uncertainty of 3.4 arcsec (90% containment). This includes the latest XRT boresight correction. The XRT 0.2-10keV light curve shows a simple power-law decay with a slope of 1.75 +/- 0.25 out to T+12.8ks. After this time the source was no longer detected, with a 3 sigma upper limit to the count rate of 2.7e-4 count/s in an exposure of 85ks. An absorbed power-law fit to the photon counting mode spectrum from T+149s to T+12.8ks gave a photon index 1.9 +1.1/-0.6 and a column density of (0.4 +0.7/-0.2)e22 cm**2. The Galactic column in this direction is 4.5E+20 cm**2. The unabsorbed 0.2-10keV flux was 1.4e-12 ergs cm**-2 s**-1. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4308 SUBJECT: GRB051117B: optical observation DATE: 05/11/29 20:04:12 GMT FROM: Alexei Pozanenko at IKI, Moscow D. Sharapov, M. Ibrahimov (MAO), A.Pozanenko (IKI),V.Rumyantsev (CrAO) on behalf of larger GRB follow up collaboration report: We observed the error box of GRB051117b (Band et al., GCN 4281) with 1.5m telescope of Maidanak Astronomical Observatory. Set of R images were taken between Oct.17 (UT) 21:31 - 21:54. No source is detected in refined XRT error box (Beardmore et al., GCN 4304). We do not detect the extended source mentioned by Chen et al. in GCN 4285. Preliminary estimation of upper limit against of USNO A2.0 is following: Mid time, Exposure, Filter, Mag. (UT) (s) Nov.17 21:46 1080 R 21.0 (3 sigma UL) The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4396 SUBJECT: GRB051117B: optical observation DATE: 05/12/27 16:02:46 GMT FROM: Daisaku Nogami at Kyoto U D. Nogami, T. Kawamura, J. Kuriyama, K. Sugiyasu, K. Kubota (Kyoto Univ.), K. Yanagisawa (Okayama Astrophys. Obs.), S. Kouzuma, H. Yamaoka (Kyushu Univ.), and N. Kawai (Tokyo Inst. of Tech.) report: We observed the field of GRB051117B (Band et al., GCN 4281) with a 50-cm telescope (MITSuME) at the Okayama Astrophysical Observatory, using a three-color (g', Rc, and Ic) CCD imager. The observations started at 14:16:22 (UT), about 54 min after the trigger time, and ended at 16:36:46 (UT). The exposure time was 60 sec, and we obtained 110 images in each band. We could not find any afterglow candidate around the error box of GRB051117B (GCN 4281). The 3-sigma upper limits in the stacked images of each band are 19.2 mag, 19.2 mag, and 19.5 mag in the g', Rc, and Ic band, respectively. These magnitudes were calibrated with the catalogs of Tycho (VT), USNO A2.0 (R), and USNO B1.0 for g', Rc, and Ic, respectively. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5025 SUBJECT: GRB 051117A: Bright host galaxy not confirmed DATE: 06/04/28 16:16:33 GMT FROM: Alexander Kann at TLS Tautenburg D. A. Kann (TLS Tautenburg), E. Palazzi, N. Masetti & E. Maiorano (INAF/IASF - Bologna) report: We observed the location of the UVOT afterglow (Holland et al., GCN 4300, Holland, GCN 4301) of GRB 051117A (Band et al., GCN 4280) with the Tautenburg 1.34m Schmidt telescope in the R filter under clear conditions and seeing of 2.8". Observations consisted of 12 x 600 s exposures, total integration time 2 hours, centered at UT 20060406.1, 139.9 days after the burst. It was suggested by the UVOT observations that an underlying extended source might have been detected at 3.5 days after the burst at a magnitude of V about 21.5 - possibly the host galaxy. The stacked Tautenburg image reveals no source at the UVOT position. The limiting magnitude at 3 sigma confidence is R = 24.0 measured against the USNOB1.0 R2 magnitudes of several unsaturated and isolated stars. This is not corrected for the very small Galactic extinction of E(B-V) = 0.024. This field has also been imaged by the fourth release of the Sloan Digital Sky Survey (Adelman-McCarthy et al. 2006, ApJS, in press), and no source is detected at the UVOT location either (our photometry is significantly deeper than the SDSS). About 2" from the UVOT localization (outside the 3 sigma UVOT localization), there is a group of four pixels slightly above the (subtracted) background. Simply transforming the sum of the counts into a magnitude gives R = 25.3, a "detection" at about one sigma significance. We caution that this is quite probably not a real source. There are no other sources closer than 5" to the UVOT position. This message may be cited.