//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4130 SUBJECT: GRB 051022: Optical observations DATE: 05/10/22 13:44:59 GMT FROM: Ken ichi Torii at RIKEN K. Torii (Osaka U.) reports on behalf of the ART collaboration: The error region of the HETE-2 GRB 051022 (Trigger number 3950) was observed by the 14 inch Automated Response Telescope. VRcIc imaging started at 2005 October 22, 13:09:49 UT (111s after the trigger) and 60s integration was repeated. Preliminary analysis of a part of the data does not show a new object brighter than R~15.8 within the 5' diameter SXC error region (GCN alert sequence number 10). Further observations and analyses are in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4131 SUBJECT: GRB051022 (=H3590), A GRB Detected By HETE DATE: 05/10/22 14:55:35 GMT FROM: Carlo Graziani at U.Chicago J-F Olive, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on behalf of the HETE Science Team; M. Arimoto, T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, N. Ishikawa, A. Kobayashi, J. Kotoku, M. Maetou, M. Matsuoka, Y. Nakagawa, T. Sakamoto, R. Sato, T. Shimokawabe, Y. Shirasaki, S. Sugita, M. Suzuki, T. Tamagawa, K. Tanaka, and A. Yoshida, on behalf of the HETE WXM Team; N. Butler, G. Crew, J. Doty, G. Prigozhin, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; M. Boer, J-P Dezalay, and K. Hurley, on behalf of the HETE FREGATE Team; report: HETE Fregate, WXM, and SXC detected GRB 051022(=H3590) at 13:07:58 on 22 October 2005. The messages sent from the satellite in real time indicate that the burst is both valid and unusually bright. Because of a dropout of the internet connection to our ground station at Cayenne, additional no data were downlinked at the last contact: if this dropout persists, we will not have complete spectral and temporal data from GRB051022 until 19h UT. The HETE team believes that the coordinates distributed in real time are correct, and we urge that followup observations of these coordinates be made. The localization distributed in real time from the WXM was RA = 23h 55m 53s, Dec = +19d 37' 43" (J2000) with a 90% confidence error region of 14' radius. The localization distributed in real time from the SXC was RA = 23h 56m 00s, DEC = +19d 35' 51" (J2000) with a 90% confidence error radius of 2.5 arcminutes. Since the SXC coordinates cannot be independently verified until after the full data set is downlinked, we urge imaging of the full WXM error region. [GCN OPS NOTE(22oct05): Per author's request, the author list was added.] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4132 SUBJECT: GRB 051022A: ROTSE-III Optical Limits DATE: 05/10/22 15:02:53 GMT FROM: Brad Schaefer at LSU B. E. Schaefer (Louisiana State University) reports on behalf of the ROTSE collaboration: ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB 051022A (HETE trigger 3950), producing images beginning 6.3 s after the GCN notice time. An automated response took the first image at 13:08:59.8 UT, 61.3 s after the burst, under fair conditions. We took 10 5-sec, 10 20-sec and 50 60-sec eposures. 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 14.5-17.2; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 13:08:59.8 13:11:23.8 144 17.4 61.3 Y 13:39:26.5 13:49:26.5 600 17.9 1888.0 Y //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4133 SUBJECT: GRB051022,optical observation DATE: 05/10/22 15:05:04 GMT FROM: Eri Sonoda at U of Miyazaki/Japan E.Sonoda,S.Maeno,Y.Tokunaga, M.Yamauchi (University of Miyazaki) "We have observed the field covering the SXC error region of GRB051022(HETE trigger 3950; trigger time 13:07:58.49 UT) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki.The observation was started 13:09:44 UT on Oct.22.We have compared our image with the USNO A2.0 catalog. Preliminary analysis shows there is no new source brighter than 17.7 mag. in the SXC error region." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4134 SUBJECT: GRB 051022: SSO40 Optical Observations DATE: 05/10/22 15:11:40 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (Caltech), D. B. Fox (Penn State), R. McNaught and B. Peterson (RSAA/ANU) report on behalf of a larger collaboration: "We have imaged the HETE localization region for GRB 051022 (Graziani, GCN 4131) with the Siding Spring Observatory 40-inch telescope. Our observations consisted of 4 x 100 s images in R-band, taken at a mean epoch of 13:23:35 UT (~ 15.6 min after the burst). We find no new sources inside the SXC error circle when compared to the Digital Sky Survey. Our limiting magnitude, calculated with respect to several Guide Star Catalog sources in the field, is ~ R > 20.0." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4137 SUBJECT: GRB 051022 (=H3950): SXC Flight Localization is Valid DATE: 05/10/22 17:33:30 GMT FROM: George Ricker at MIT GRB 051022 (=H3950): SXC Flight Localization is Valid K. Tanaka, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on behalf of the HETE Science Team; M. Arimoto, T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, N. Ishikawa, A. Kobayashi, J. Kotoku, M. Maetou, M. Matsuoka, Y. Nakagawa, T. Sakamoto, R. Sato, T. Shimokawabe, Y. Shirasaki, S. Sugita, M. Suzuki, T. Tamagawa, and A. Yoshida, on behalf of the HETE WXM Team; N. Butler, G. Crew, J. Doty, G. Prigozhin, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE FREGATE Team; report: The HETE team, after reviewing the the real-time messages from HETE regarding GRB 051022(=H3950), believes that the SXC real-time localization of this burst is valid. As reported in GCN Notices beginning 118 seconds after the initial trigger and in GCN Circular 4131, the SXC real-time localization can be described as a circle centered at RA = 23h 56m 00s, DEC = +19d 35' 51" (J2000) with a 90% confidence error radius of 2.5 arcminutes. This SXC localization corresponds not only to the highest correlation peak in the WXM error circle, but also to the highest correlation peak in the entire SXC field-of-view. Therefore GRB 051022 was sufficiently bright in soft X-rays that the SXC position was determined independently of the WXM result. In addition, there is good reason to believe that the duration of GRB 051022 is > 2-4 minutes and that there are periods of low emission during the X-ray prompt emission. These indications, combined with the upper limit of R > 20 by Cenko et al (GCN 4134), suggest that searches at NIR and infrared wavelengths for a high redshift object in the SXC error region would be of interest. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4139 SUBJECT: IPN triangulation of GRB051022 (=H3950) DATE: 05/10/22 18:59:28 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses and Mars Odyssey GRB teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara, and R. Starr, on behalf of the GRS-Odyssey GRB team, and E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, report: Mars Odyssey and Konus-Wind observed GRB051022 (=H3950, GCN 4131 and 4137). We have triangulated it to an annulus centered at RA, Decl(J2000)=47.9138, +16.5422 degrees, whose radius is 46.4533 +/- 0.0684 degrees (3 sigma). The center line of this annulus passes 0.004 degrees from the HETE SXC position, and the annulus just encompasses the SXC error circle, without substantially reducing its area. We also confirm that this burst was exceptionally bright, and that its duration, as observed by HEND (>~50 keV), was about 200 s. More details will follow. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4141 SUBJECT: GRB051022: Swift XRT Position DATE: 05/10/22 22:28:14 GMT FROM: Judith Racusin at PSU J. Racusin, D. Burrows (PSU), N. Gehrels (GSFC) on behalf of the Swift XRT team: XRT began observing the field of HETE discovered GRB051022 (Olive et al., GCN 4131) at 16:35:54 UT, approximately 3.5 hours after the trigger. Using 2 orbits of data, we detect a bright uncatalogued fading X-ray source at the following coordinates: RA(J2000): 23 56 4.1 Dec(J2000): +19 36 25.1 with an estimated uncertainty of 4 arcseconds (90% containment), including corrections for the XRT boresight offset. This position is 67 arcseconds from the HETE position Tanaka et al. (GCN 4137). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4143 SUBJECT: GRB 051022, J & K-band observation DATE: 05/10/23 03:13:26 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. J. Castro-Tirado, A. de Ugarte Postigo (IAA-CSIC, Granada, Spain), G. Bihain (IAC, La Laguna, Spain), S. Guziy, S. B. Pandey, M. Jelinek and J. Gorosabel (IAA-CSIC, Granada, Spain), report: "We have observed the HETE-2 error box for GRB 051022 (Olive et al., GCNC 4131) with the 1.5 m Carlos Sánchez telescope at Tenerife, Spain. 30 min exposures in the J and Ks-band filters were taken starting on October 22 (01:56 UT, i.e. 12.8 hr after the GRB). Within the SWIFT X-ray error box (Racusin et al., GCNC 4141), we detect two objects, at coordinates (J2000): #A RA= 23 56 04.10 Dec= +19 36 27.9 #B RA= 23 56 04.18 Dec =+19 36 23.1 Preliminary error is 1.0". Object #A seems to be present in the DSS-2 (IR). Object #B seems much redder than #A and marginally consistent with another possible source seen in the DSS-2 (IR). Additional observations in the near-IR are requested to confirm if object #B is the nIR afterglow to GRB 051022. An ID-chart will be posted at http://www.iaa.csic.es/~deugarte/GRBs/grb051022.gif ." Alberto J. Castro-Tirado wrote: [GCN OPS NOTE(25oct05): The name on the 4131 reference was changed from Graziani to Olive (in response to the author change on 4131).] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4145 SUBJECT: GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed DATE: 05/10/23 04:04:49 GMT FROM: Don Lamb at U.Chicago GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed J. Doty, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on behalf of the HETE Science Team; M. Arimoto, T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, N. Ishikawa, A. Kobayashi, J. Kotoku, M. Maetou, M. Matsuoka, Y. Nakagawa, T. Sakamoto, R. Sato, T. Shimokawabe, Y. Shirasaki, S. Sugita, M. Suzuki, T. Tamagawa, K. Tanaka, and A. Yoshida, on behalf of the HETE WXM Team; N. Butler, G. Crew, G. Prigozhin, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE FREGATE Team; report: We have performed a spectral analysis of the WXM and FREGATE spectral data for GRB 051022. Fitting a power-law times exponential (PLE) model jointly to the WXM and FREGATE spectral data yields a chi^2 of 185 for 139 DOF, while fitting a PLE model with absorption yields a chi^2 of 131 for 138 DOF. Fitting a Band model jointly to the WXM and FREGATE spectral data also yields a chi^2 of 131 for 138 DOF. These results show that the data strongly favor a PLE model with absorption over a PLE model alone, and that a PLE model with absorption gives a satisfactory fit to the data. They also show that the data do not request a Band model with absorption. The best-fit spectral parameters for the PLE model with absorption are alpha = -1.22+/-0.02, E_peak = 306 + 31/-26 keV, and n_H = 1.7 ± 0.4 x 10^22 atoms cm^-2. The fluence is (2.2 ± 0.02) x 10^-5 erg cm^-2 in the 2-30 keV energy band and (1.4 ± 0.02) x 10^-4 erg cm^-2 in the 30-400 keV energy band. The ratio log(S_x/S_g) = -1.8, so GRB 051022 is a "classical" hard GRB. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4148 SUBJECT: GRB 051022: Magellan NIR imaging DATE: 05/10/23 08:07:53 GMT FROM: Edo Berger at Carnegie Obs E. Berger and P. Wyatt (Carnegie Observatories) report: "We observed the error circle of GRB 051022 (GCN 4131) with the PANIC near-IR camera on the Magellan/Baade telescope starting on 2005 Oct 22.105 UT (13.4 hr after the burst). We obtained a total of 18 min in the J and K bands. Within the XRT error circle (GCN 4141) we detect a single source which coincides with source B of Castro-Tirado et al. (GCN 4143). This source is clearly extended. We also detect source A of Castro-Tirado et al. but note that this source is located about 1.5" outside of the XRT error circle and it is also extended." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4149 SUBJECT: GRB051022: Optical Observations DATE: 05/10/23 08:25:30 GMT FROM: Richard J. Cool at U.of AZ/Steward Obs Richard Cool (Arizona) reports: On 23 October 2005 UT, we observed the XRT error circle or GRB051022 (Racusin et al GCN 4141) with the WIYN 0.9m telescope on Kitt Peak through a Johnson R filter. We observed the field twice for 60 minutes at mean epochs JD 2453666.6068 and 2453666.7148. Near the reported XRT position, we find three sources. An image can be found at http://mizar.as.arizona.edu/~rcool/grb/grb051022.jpg Two of these sources, A (R=20.31) and B (R=21.51) are detected in DSS images, while the third source, C (R=21.21), is not. Photometry is calibrated relative to nearby USNO stars. Our sources A and B are consistent with the positions of sources A and B from Castro-Tirado et al (GCN 4143). Object C, which does not appear in DSS images, lies 7" from the location from the Swift XRT. Source C appears point-like in our images and is located at alpha J2000 = 23:56:04.2 delta J2000 = 19:36:32.3 There is a fainter source to the SW of object B, but at R=22.1, this source is below the detection threshold of the DSS images, and thus it is unclear if the source is transient. None of the objects detected appear to fade between our observational epochs. Of the sources near the XRT position, object C is the most favorable as the afterglow from the GRB due to its absence in the DSS images, but its distance from the XRT localization makes this interpretation suspect. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4150 SUBJECT: Konus-Wind observation of GRB 051022 DATE: 05/10/23 15:19:17 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team report: The long intense GRB 051022 (HETE trigger #3590; Graziani, GCN 4131) triggered Konus-Wind at T0=47305.298 s UT (13:08:25.298) The total burst duration is ~200 sec. The time-integrated spectrum of the GRB (from T0 to T0+197.12 sec) is well fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model: dN/dE ~ E^(-alpha) * exp(-E/E0) with alpha = 1.176 +/- 0.038 and E0 = 619 (-61, +71) keV (chi^2 = 55/61 dof). The peak energy Ep = 510 (-33, +37) keV. This Ep value is significantly larger than the Ep=306 (+31, -26) keV derived by HETE (Doty et al., GCN 4145), while the alpha values are in agreement. Probably, this discrepancy in Ep is due to the limited energy range of the FREGATE. As observed by Konus-Wind the burst had a fluence 2.61(-0.11, +0.06)x10^-4 erg/cm2 and peak flux on 64-ms time scale (1.00 +/- 0.13)x10^-5 erg/cm2/sec (both in the 20 keV - 2 MeV energy range). All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4152 SUBJECT: GRB 051022: SOAR JKs Observations DATE: 05/10/23 21:41:56 GMT FROM: Melissa Nysewander at UNC,Chapel Hill M. Nysewander, E. Cypriano, A. LaCluyze, M. Bayliss, D. Reichart, A. Alvarez, P. Ugarte report on behalf of the UNC team of the FUN GRB Collaboration: We observed the XRT localization (Racusin et al., GCN 4141) of HETE GRB 051022 (Olive et al., GCN 4131) with 4.1m SOAR beginning 11.2 hours after the burst, in J and Ks. We detect both A and B of Castro-Tirado et al. (GCN 4143) and report that neither appear to be fading in Ks between 11.8 and 14.4 hours after the burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4153 SUBJECT: GRB051022: IR observations DATE: 05/10/23 23:13:38 GMT FROM: Josh Bloom at UC Berkeley J. S. Bloom (UCB) reports: "We observed the field of GRB051022 (GCN 4131; GCN 4137) with the PAIRITEL 1.3m starting at 2005-10-23 04:00:34 UTC. In a total exposure of 1836 seconds we detect in JHKs the three sources (A,B: Castro-Tirado et al. GCN 4143; C: Cool GCN 4149) near the XRT position (GCN 4141). We note that only source B is consistent with the current XRT position. An image has been posted to: http://astro.berkeley.edu/~jbloom/grb051022_ir.gif (the XRT position marked as a white circle) Further observations are planned." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4154 SUBJECT: GRB051022: Radio Counterpart DATE: 05/10/24 03:58:57 GMT FROM: Patrick B. Cameron at Caltech P. B. Cameron (Caltech) and D. A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie collaboration: "We observed the field of GRB 051022 (GCN 4131; GCN 4137) with the Very Large Array at 8.5 GHz beginning October 24.09 UT. We find a bright radio source with a flux density of 585 +/- 49 uJy at: RA(J2000) = 23 56 04.1 DEC(J2000) = +19 36 24.1 Within our current astrometric errors (of order 1 arcsec) the source is coincident with Source B (GCN 4143). We intend to refine this position with further observations. We note that there is a nearby, extended radio source whose centroid is located 15 arcsec to the northwest that is also detected in the NVSS survey (Condon et al. 1998, AJ, 115, 1693). However, the point source is clearly offset from the centroid of this extended emission and is not visible in the NVSS. We identify this point source as the likely afterglow from GRB051022. 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: 4155 SUBJECT: GRB 051022: Swift/UVOT Upper Limits DATE: 05/10/24 07:06:22 GMT FROM: Stefan Immler at NASA/GSFC S. Immler (GSFC), A. Retter (PSU), J. Racusin (PSU), L. Cominsky (Sonoma State U), J. Norris (GSFC) on behalf of the Swift/UVOT team report: The Swift-UVOT began observing the field of GRB 051022 (HETE Trigger H3950; Olive et al. GCN 4131) at 2005-10-22 16:34:11, about 3.5 hours after the burst. Based on comparisons with the DSS catalog, we detect no source inside the XRT error circle at RA, Dec 23:56:4.1, +19:36:25.1 (J2000) with an uncertainty of 4 arcsec (Racusin et al. GCN 4141) in any of the 5 filters or in summed V-band exposures down to the following 5-sigma magnitude upper limits: Filter T_range(hours) Exp(sec) 5sigUL V 3.47-3.72 900 19.5 B 5.63-5.65 63 18.9 U 5.38-5.63 900 20.1 W1 3.98-4.36 900 19.3 M2 3.73-3.98 900 20.4 V 6.78-13.48 7914 20.7 where T_range is the time post HETE trigger. The magnitudes have not been corrected for extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4156 SUBJECT: GRB051022: host galaxy redshift DATE: 05/10/24 07:56:02 GMT FROM: Avishay Gal-Yam at Caltech A. Gal-Yam (Caltech), E. Berger (OCIW), D. B. Fox (Penn State), A. M. Soderberg, S. B. Cenko, P. B. Cameron (Caltech) and D. A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie collaboration: "We observed galaxy "B" (GCN 4143), located within the XRT error circle of the HETE GRB 051022 (GCN 4131; 4137; 4141) and coincident with the radio afterglow detected by Cameron et al. (GCN 4154), using the double spectrograph mounted on the 200" Hale telescope at Palomar Observatory. Preliminary reduction of a 3600s-long red spectrum of this galaxy reveals a strong line at observed wavelength 6736 Angstrom which we identify as OII 3727 at z=0.8. This identification is supported by weaker detections of OIII 5007 and 4959, as well as Hbeta and Hgamma. We conclude that the likely host of GRB 051022 is at z=0.8. Further analysis is underway." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4157 SUBJECT: GRB 051022, mm counterpart DATE: 05/10/24 12:56:28 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia M. Bremer (IRAM, Grenoble), A. J. Castro-Tirado (IAA-CSIC, Granada) and R. Neri (IRAM), on behalf of a large collaboration, report: "On Oct 23.9 UT we have undertaken millimetre observations (3 mm) with the Plateau de Bure Interferometer of source "B" (Castro-Tirado et al., GCNC 4143), related to the HETE-2 GRB 051022 (Olive et al., GCNC 4131). We found a ~1 mJy source (4 sigma) at coordinates: AR(2000) = 23:56:04.14 Dec(2000) = +19:36:25.4 The astrometrical error is 0.5" (1-sigma), consistent with the position of source B and the VLA radio counterpart detected on Oct 24.1 (Cameron et al. GCNC 4154). We will continue to monitor the source. " [GCN OPS NOTE(25oct05): The name on the 4131 reference was changed from Graziani to Olive (in response to the author change on 4131).] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4158 SUBJECT: GRB 051022: WSRT Radio Detection DATE: 05/10/24 13:38:25 GMT FROM: Alexander van der Horst at U of Amsterdam A.J. van der Horst (University of Amsterdam), E. Rol (University of Leicester) and R.A.M.J. Wijers (University of Amsterdam) report on behalf of a larger collaboration: "We observed the HETE GRB 051022 (GCN 4131) at 4.9 GHz with the Westerbork Synthesis Radio Telescope on October 23 from 15.34 to 20.34 UT, i.e. 1.09 - 1.30 days after the burst. We detect a radio source with a flux density of 270 +/- 30 microJy at the position of the bright radio source at 8.5 GHz (GCN 4154). This source is within the Swift XRT error box (GCN 4141), and coincides with the sources A and B (GCN 4143) within our positional errors. We also detect the bright nearby NVSS source northwest of the likely GRB051022 afterglow (GCN 4154), with a flux density of 1382 +/- 30 microJy. Further observations are planned." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4161 SUBJECT: GRB 051022 Chandra Observations scheduled DATE: 05/10/25 15:58:26 GMT FROM: Chryssa Kouveliotou at MSFC C. Kouveliotou, S. Patel (NASA/MSFC), E. Rol (University of Leicester) report on behalf of a larger team: We have triggered our accepted Chandra Guest Investigation on dark Gamma Ray Bursts for GRB051022. A CXO observation of 20 ks will commence today at 21:44:42 UT. We plan to analyze the data by the end of the day and send out a first source location with at least an aspect solution uncertainty (0.7"). A more accurate location using astrometry will be reported as soon as the complete data set is available. We urge follow up observations of the source in radio and IR. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4163 SUBJECT: Chandra Observations of GRB 051022 DATE: 05/10/26 02:56:00 GMT FROM: Sandeep K. Patel at NSSTC-NASA/MSFC S. Patel, C. Kouveliotou (NASA/MSFC), E. Rol (University of Leicester) report on behalf of a larger team: We processed the initial 700 s (on source) of our ongoing Chandra ACIS-S observation of GRB 051022, which started on October 25, 21:14:20 UT. We detect an X-ray source consistent with the VLA source location (Cameron & Frail, GCN # 4154) with a count rate of 0.026 c/s in the entire Chandra band. The Chandra source location is centered at RA=23h56m4.1s and DEC= +19deg 36' 23.9". We estimate an error of 0.7" dominated by the uncertainty in the Chandra aspect solution. A more accurate position based on astrometry may be possible after the complete observation of 20 ks is available. We are grateful to the Chandra Data Center for the rapid data processing, in particular Drs Joy Nichols and Craig Anderson. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4164 SUBJECT: GRB 051022, refined optical astrometry DATE: 05/10/26 11:32:28 GMT FROM: Sergei Guziy at IAA A. de Ugarte Postigo, F. J. Aceituno and S. Guziy (IAA-CSIC Granada, Spain), on behalf of a large collaboration, report: "We have performed new astrometric measurements of the host galaxy of GRB 051022 (Olive et al. GCNC 4131, Castro-Tirado et al. GCNC 4143) using a deep V-band image taken with the 1.5 m telescope at Observatorio de Sierra Nevada on Oct 24.9 UT. Coordinates yield (J2000): AR: 23:56:04.10 Dec:+19:36:24.2 with 0".5 error (based on USNO-A2.0). This is consistent, within errors, with the positions earlier reported in nIR (GCNC 4143), radio (Cameron et al. GCN 4154), mm (Bremer et al. GCNC 4157) and X-rays (Patel et al. GCNC 4163)." [GCN OPS NOTE(26oct05): Per author's request, "in optical (GCNC 4143)" was changed to "in nIR (GCNC 4143)" and "Patel et al. GCNC 4146" was changed to "Patel et al. GCNC 4163.] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4165 SUBJECT: GRB 051022: XRT Refined Spectral and Temporal Analysis DATE: 05/10/26 13:51:17 GMT FROM: George Ricker at MIT N. R. Butler (UC-Berkeley), G. R. Ricker (MIT), D. Q. Lamb (U.Chicago), D. N. Burrows (PSU), J. Racusin (PSU), and N. Gehrels (GSFC) report: We have performed spectral and temporal analyses of the first three Swift XRT ToO follow-up observations of the HETE-2--localized burst GRB 051022 (Olive et al., GCN 4131; Tanaka et al. 4137; Doty et al. 4145). Localization of the X-ray afterglow of the burst was reported by Racusin et al. (GCN 4141) based on the first two orbits of XRT data. The PC mode data that we have analyzed have an effective exposure of 14.2 ksec for the time period of 12.5 to 182.3 ksec after the burst. Modeling the count rate decay in the 0.5-10 keV band as a power-law in time, the best-fit decay index is alpha = 1.33 +/- 0.07. There is no evidence for a jet break in the XRT data that we have analyzed. The 0.2-10 keV spectrum is well-fit (Chi2/nu = 189/172) by a power-law model with absorption. We find n_H = (0.84 +/- 0.07) x 10^22 cm^-2, roughly consistent with the value derived from the HETE-2 WXM and FREGATE data (Doty et al., GCN 4145) and greater than the Galactic value in the direction of the burst at the 30-sigma significance level, using the Likelihood Ratio test (Delta Chi2 = 890 for one additional degree freedom). The photon index is gamma = 2.0 +/- 0.1 and the mean unabsorbed flux is (1.9 +/- 0.1) x 10^-11 erg cm^-2 s^-1. The spectral parameters do not appear to evolve in time during the observation. Assuming the relationship A_V = 0.56 N_H[10^21 cm^-2] + 0.23 found by Predehl and Schmitt (1995; A&A, 293, 889); the expression for the extinction curve given by Cardelli, Clayton, and Mathis (1989; ApJ, 345, 245); R_V = 3.1; and a redshift for the burst of z = 0.8 (Gal-Yam et al., GCN 4156), based on the positional coincidence between the galaxy at this redshift and the IR/optical (Castro-Tirado et al., GCN 4143; de Ugarte Postigo et al., GCN 4164) and radio (Cameron and Frail, GCN 4154; van der Horst, Rol, and Wijers, GCN 4158) and X-ray afterglow (Patel, Kouveliotou, and Rol, GCN 4163) of the burst, we derive the following values for the extinction in magnitudes in the observer frame: A_V = 8.6 +/- 0.7, A_R = 7.7 +/- 0.6, A_I = 6.5 +/- 0.5, A_J = 3.8 +/- 0.3, A_H = 2.3 +/- 0.2, and A_Ks = 1.5 +/- 0.1. [GCN OPS NOTE(26oct05): This is a reissue of GCN Circ 4165 with the binary-conversion characters removed and the line-break formating fixed.] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4169 SUBJECT: GRB051022: Swift XRT measurement of jet break DATE: 05/10/27 17:10:41 GMT FROM: Judith Racusin at PSU J. Racusin, J. Kennea, D. Fox, D. Burrows, N. Cucchiara (PSU), P. Schady (MSSL), A. Wells (U. Leicester), N. Gehrels, T. Sakamoto (GSFC), C. Kouveliotou (MSFC), S. Patel (MSFC) on behalf of the Swift XRT team: We have analyzed the observations of the X-ray afterglow (Racusin et al., GCN 4141, Butler et al, GCN4165) of GRB 051022 (Olive et al., GCN 4131) beginning approximately 3.5 hours after its discovery by HETE on October 22 and continuing for 4.8 days. We find the early decay slope of 1.33 +/- 0.07 (Butler et al, GCN 4165) extends to 2.9 +/- 0.2 days after the burst, after which it steepens to a late time decay slope of 3.6 +/- 0.4. Further observations are planned. Given the redshift of 0.8 (Gal-Yam et al., GCN 4156) and the different measured fluences and Epeak by Konus-Wind (Golenetskii et al., GCN 4150) and HETE (Doty et al, GCN 4145), assuming n=0.1 cm^-3 and our jet break time, we calculate the following Eiso, Egamma, and jet opening angles: HETE: alpha=-1.2, beta=-10.0, Epeak=306 keV, 2-400 keV fluence=1.6e-4 erg cm-2 Eiso = 3.8e53 erg Jet opening angle = 4.3 degrees Egamma = 1.1e51 erg Konus-Wind: alpha=-1.2, beta=-10.0, Epeak=510 keV, 20 keV-2 MeV fluence=2.6e-4 erg cm-2 Eiso = 3.1e53 erg Jet opening angle = 4.4 degrees Egamma = 9.1e50 erg //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4170 SUBJECT: GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction DATE: 05/10/28 01:19:53 GMT FROM: George Ricker at MIT GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction N. R. Butler (UC-Berkeley), G. R. Ricker (MIT), D. Q. Lamb(U. Chicago), D. N. Burrows (PSU), J. Racusin (PSU), and N. Gehrels (GSFC) report: In our calculation (Butler et al. GCN 4165) of the extinction of the optical and NIR afterglow of GRB 051022 in the observer frame implied by the best-fit value of the absorption of the X-ray afterglow measured by the Swift XRT, we did not take into account the transformation between the absorption of the X-ray spectrum as measured in the observer frame and that measured in the rest frame of the host galaxy. Taking this transformation into account, and using the same method as that described in Butler et al. (GCN 4165), we derive the following values for the extinction in magnitudes in the observer frame: A_V = 41.1 +/- 3.4, A_R = 36.7 +/- 3.0, A_I = 30.9 +/- 2.5, A_J = 17.6 +/- 1.5, A_H = 10.8 +/- 0.9, and A_Ks = 6.8 +/- 0.6. These values for the extinction are large enough to account for the failure to detect the afterglow of GRB 051022 in either the optical (Torii GCN 4130; Schaefer GCN 4132; Sonoda et al., GCN 4133; Cenko et al., GCN 4134; Cool GCN 4149; Immler et al., GCN 4155) or the NIR (Castro-Tirado et al., GCN 4143; Berger and Wyatt, GCN 4148: Nysewander et al., GCN 4152; Bloom GCN 4153), provided that most of the dust is not destroyed by the burst and/or its afterglow. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4181 SUBJECT: GRB 051022: RTT150 optical observations DATE: 05/10/30 06:44:16 GMT FROM: Rodion Burenin at IKI, Moscow R. Burenin, D. Denisenko, M. Pavlinsky, R. Sunyaev (IKI), I. Khamitov, Z. Aslan (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.), I. Bikmaev, N. Sakhibullin (KSU/AST) report: The error box of GRB 051022 (Olive et al., 4131; Tanaka et al., 4137) was observed with Russian-Turkish 1.5-m telescope (RTT150, Bakyrlytepe, TUBITAK National Observatory, Turkey) in R, starting at Oct. 22, 16:16 UT, i.e. 3.15 hours after the burst. The galaxy, where X-ray afterglow was detected with XRT (Racusin et al., GCN 4141) and later with Chandra (Patel et al., GCN 4163), appears in our images as clearly extended source. Its optical flux is stable within 0.1mag during our observations, i.e. till 20:00 UT, therefore we detected no variable source superimposed on this galaxy. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4184 SUBJECT: Recent GRB UBVRcIc field photometry DATE: 05/10/31 16:31:02 GMT FROM: Arne A. Henden at AAVSO A. Henden (AAVSO/USNO) reports on behalf of the USNO GRB Team: We have acquired UBVRcIc all-sky photometry for 23x23arcmin fields centered on the coordinates of recent GRB localizations with the USNOFS 1.0-m telescope on 1 or 2 photometric nights. We are using a new CCD, and so place an additional zeropoint error of about 0.03mag that should be added in quadrature to the errors reported in the files listed below. Stars brighter than V=13.0 are saturated and should be used with care. We have placed the photometric data on our anonymous ftp site: ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050505.dat ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb051021.dat ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb051022.dat ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb051028.dat Since these bursts had identified optical afterglows, we may improve the photometric calibration on subsequent observing runs. As always, you should check the dates on the .dat file prior to final publication to get the latest photometry. There is a README file on the ftp directory to give you information about the procedures used to calibrate these fields.