//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15464 SUBJECT: GRB 131108A: Fermi-LAT onboard detection of a burst DATE: 13/11/08 21:39:17 GMT FROM: Judith Racusin at GSFC J. L. Racusin (NASA/GSFC), S. Zhu (NASA/GSFC/UMD), D. Kocevski (NASA/GSFC/ORAU), M. Ohno (Hiroshima), N. Omodei (Stanford), E. Troja (NASA/GSFC/CRESST) and G. Vianello (Stanford), report on behalf of the Fermi LAT team: At 20:41:55.76 UTC on November 8, 2013, Fermi LAT triggered onboard on high energy emission from GRB 131108A. The burst was also detected by GBM (trigger 131108863/405636118), and triggered an autonomous repoint of the spacecraft. This is the first onboard trigger since 2009, indicating a potentially rare and exciting event. The onboard location is R.A., Dec. 156.47, +9.90 (J2000) with an approximate error radius of 0.5 deg, seeded by the GBM detected position. This was 27 deg from the LAT boresight at the time of the trigger. We anticipate providing a refined location within the next 12-15 hours when the LAT science data for this burst is downlinked and processed. The Fermi LAT point of contact for this burst is Masanori Ohno (ohno@hep01.hepl.hiroshima-u.ac.jp). A Swift TOO request has been approved. The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15465 SUBJECT: GRB 131108A Tiled Swift observations DATE: 13/11/08 21:49:51 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the Fermi/LAT GRB 131108A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00021 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the Fermi/LAT event is high: any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; and 2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15466 SUBJECT: IPN triangulation of GRB 131108A DATE: 13/11/08 22:58:31 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team, S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, and A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report: GRB 131108A (GCN 15464) has been observed by MESSENGER and INTEGRAL (SPI-ACS) so far. We have triangulated it to a preliminary annulus centered at RA(2000)=211.006 degrees, Dec(2000)=-10.955 degrees, with radius 57.980 +/- 0.055 degrees (3 sigma). This annulus intersects the LAT error circle, reducing its area by about a factor of 7, and forming an error box whose area is approximately 390 sq. arcmin., and whose corners are RA(2000) Dec(2000) 156.363 o=10 h 25 m 27 s 9.411 o= 9 o 24 ' 40 " 156.702 o=10 h 26 m 48 s 10.345 o= 10 o 20 ' 42 " 156.477 o=10 h 25 m 54 s 9.400 o= 9 o 24 ' 00 " 156.797 o=10 h 27 m 11 s 10.283 o= 10 o 16 ' 57 " A map has been posted at ssl.berkeley.edu/ipn3/130811A. This error box can be improved. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15467 SUBJECT: IPN triangulation of GRB 131108A - correction DATE: 13/11/08 23:20:38 GMT FROM: Kevin Hurley at UCBerkeley/SSL The URL given in GCN 15466 was incorrect. The correct URL is ssl.berkeley.edu/ipn3/131108A. I apologize for the confusion and thank those of you who quickly pointed this out. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15468 SUBJECT: GRB 131108A: Swift detection of a possible X-ray afterglow DATE: 13/11/09 03:31:55 GMT FROM: Michael Stroh at PSU/Swift M. C. Stroh and J. A. Kennea (PSU) report on behalf of the Swift/XRT team: Swift-XRT has observed the error circle of the Fermi/LAT GRB 131108A (Racusin et al., GCN #15464, Evans, GCN #15465) in a series of observations tiled on the sky. In 621 s of data, beginning 3.9 ks after the Fermi/LAT trigger, we detect a bright, fading, uncatalogued X-ray source at RA, Dec = 156.50066, 9.66232 which is equivalent to: RA (J2000.0) = 10h 26m 0.16s Dec (J2000.0) = +09d 39' 44.4" with an uncertainty of 3.6 arcsec (radius, 90% confidence). We note that this position lies 14.4' from the center of the Fermi/LAT error circle (GCN #15464), consistant with that position, and inside the IPN error box (GCN #15466). This previously uncatalogued source is significantly brighter than the RASS limit and fading, and we thus consider it the likely GRB afterglow. The source was detected in 2 overlapping fields, with target IDs: 00020321, 00020322. The results of the automated XRT processing of the source in these fields are available at: http://www.swift.ac.uk/xrt_products/TILED_GRB00021/00020321 http://www.swift.ac.uk/xrt_products/TILED_GRB00021/00020322 This circular is an official product of the Swift-XRT team.//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15469 SUBJECT: GRB 131108A: 1.23m CAHA optical candidate DATE: 13/11/09 03:59:02 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (IAA-CSIC/UPV-EHU), S. Mottola (DLR), A. de Ugarte Postigo (IAA-CSIC/DARK-NBI), S. Hellmich (DLR), G. Proffe (DLR), report on behalf of a large collaboration: We imaged the field of GRB 131108A (Racusin et al. GCNC 15464) with the 1.23m CAHA telescope. The observations were carried out in the V-band starting at 03:28:33 UT. A bright V~18.5 object not present on the DSS is detected consistent with the possible X-ray afterglow position (Stroh & Kennea, GCNC 15468). Further observations are in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15470 SUBJECT: GRB 131108A: Redshift from 10.4m GTC DATE: 13/11/09 05:35:00 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC), J. Gorosabel (IAA-CSIC), R. Sanchez-Ramirez (IAA-CSIC), J.P.U. Fynbo (DARK/NBI), N.R. Tanvir (U. Leicester), A. Cabrera-Lavers (ULL/IAC) and A. Garcia (ULL/IAC) report on behalf of a larger collaboration: We have observed the afterglow of the Fermi-LAT GRB 131108A (Racusin et al. GCN 15464, Hurley et al. GCN 15466, Stroh et al. GCN 15468, Gorosabel et al. GCN 15469) with the 10.4m GTC telescope at Roque de los Muchachos Observatory (La Palma, Spain) starting at 04:50 UT (8.13 hr after the burst). The observation consisted of 3x600 s and was performed with the R1000B grism, that covers the range from 3700 to 7500 A at a resolution of ~1000. Observations were performed with a poor seeing of ~2.2". The afterglow is detected in the acquisition frame with at a magnitude of r=18.9, as compared with the SDSS. A preliminary reduction of the spectrum shows a strong trace and is characterised by a strong Ly-alpha absorption as well as absorption features which include SII, SiII, SiII*, OI, CII, SiIV, CIV and AlII at a common redshift of z=2.40, which we identify as the redshift of the GRB. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15471 SUBJECT: GRB 131108A: NOT optical observations DATE: 13/11/09 06:11:42 GMT FROM: Dong Xu at DARK/NBI D. Xu, D. Malesani (DARK/NBI), T. Pursimo (NOT) report on behalf of a larger collaboration: We observed the Swift/XRT field of Fermi-detected GRB 131108A (Racusin et al., GCN 15464; Stroh & Kennea, GCN 15468) using the 2.5m Nordic Optical Telescope (NOT) equipped with the MOSCA camera. We obtained SDSS ugriz frames, starting at 04:46:48 UT on 2013-11-09 (i.e., 8.081 hr after the Fermi/LAT trigger). The optical afterglow is detected at the border of the XRT error circle reported in Stroh & Kennea (GCN 15468) at coordinates R.A. (J2000) = 10:26:00.48 Dec. (J2000) = +09:39:44.05 Error Radius: ~0.5 arcsec thus being consistent with the XRT position, as reported in Gorosabel et al. (GCN 15469). In particular, the ugriz SED shows a clear drop at the wavelength range corresponding to the spectroscopic redshift of z=2.40 in de Ugarte Postigo et al. (GCN 15470). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15472 SUBJECT: GRB 131108A: Fermi-LAT refined analysis DATE: 13/11/09 11:04:27 GMT FROM: Giacomo Vianello at SLAC G. Vianello (Stanford), N.Omodei (Stanford), J.Racusin (NASA/GSFC) and M. Ohno (Hiroshima) report on behalf of the Fermi LAT team: We have analyzed 1.5 ks of data for GRB 131108A which triggered onboard Fermi/LAT (Racusin et al, GCN 15464) as well as Fermi/GBM. We confirm the detection of the GRB in our standard analysis at the position of the afterglow candidate (Stroh and Kennea, GCN 15468; Gorosabel et al., GCN 15469; de Ugarte Postigo et al., GCN 15470), with a very large significance (>> 10 sigma). As seen by Fermi/LAT the burst is bright, but relatively soft. In this preliminary analysis the light curve appears well correlated with the emission at lower energy, as seen by Fermi/GBM. More than 118 photons above 100 MeV and more than 3 photons above 1 GeV are observed within 1500 seconds. The highest energy photon is a 1.5 GeV event which is observed 66 seconds after the GBM trigger, which at redshift 2.4 (GCN 15470) corresponds to 5 GeV rest-frame. The time-integrated spectrum in the same time interval can be well described by a power law with photon index -2.66 +/- 0.12, with a mean flux of 1.0e-08 +/- 1.3e-09 erg/cm2/s (100 MeV - 100 GeV). Fermi-LAT pointed observations are ongoing. The Fermi LAT point of contact for this burst is Masanori Ohno ( ohno@hep01.hepl.hiroshima-u.ac.jp). The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15473 SUBJECT: GRB 131108A: TAROT-Calern optical observation DATE: 13/11/09 11:51:06 GMT FROM: Bruce Gendre at ASDC Klotz A., Turpin D. (IRAP-CNRS-OMP), Pelassa V. (UAH), Gendre B., Boer M., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 131108A detected by Fermi-LAT and Fermi-GBM (Racusin et al., GCN 15646) with the TAROT robotic telescope (D=25cm) located at the Calern Observatory, France. The observations started about 22700s after the GRB trigger (3:00 UT on 2013-11-09), when the object started to be visible. The weather conditions were poor, with only one sequence of 6 images being not cloudy. We detect the afterglow reported by Stroh et al. (GCN 15468) and Gorosabel et al. (GCN 15469), with a magnitude of R = 17.8 +/- 0.2. Magnitudes were estimated with the nearby NOMAD1 stars and are not corrected for galactic dust extinction. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15474 SUBJECT: GRB 131108A: Swift-XRT observations DATE: 13/11/09 15:26:33 GMT FROM: Michael Stroh at PSU/Swift M. C. Stroh and J. A. Kennea (PSU) report on behalf of the Swift-XRT team: We have analysed 7.9 ks of XRT data for the Fermi/LAT-detected burst: GRB 131108A, from 25.9 ks to 49.8 ks after the Fermi/LAT trigger. The data are entirely in Photon Counting (PC) mode. An X-ray source is detected within the Fermi/LAT error circle. Using 4560 s of PC mode data and 6 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 156.50178, +9.66248 which is equivalent to: RA (J2000): 10h 26m 00.43s Dec(J2000): +09d 39' 44.9" with an uncertainty of 1.6 arcsec (radius, 90% confidence). This position is 14.4 arcmin from the center of the Fermi/LAT error circle (GCN #15464), consistant with that position, and inside the IPN error box (GCN #15466). The light curve can be modelled with a power-law decay with a decay index of alpha=1.9 (+0.7, -0.6). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.2 (+0.4, -0.3). The best-fitting absorption column is 9.9 (+7.6, -6.5) x 10^20 cm^-2, in excess of the Galactic value of 3.2 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.2 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 9.9 (+7.6, -6.5) x 10^20 cm^-2 Galactic foreground: 3.2 x 10^20 cm^-2 Excess significance: 1.7 sigma Photon index: 2.2 (+0.4, -0.3) If the light curve continues to decay with a power-law decay index of 1.9, the count rate at T+24 hours will be 5.2 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x 10^-13 (2.4 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020326. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15475 SUBJECT: GRB 131108A: RATIR Optical and NIR Observations DATE: 13/11/09 16:32:22 GMT FROM: Eleonora Troja at GSFC Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of the LAT GRB 131108A (Racusin, et al., GCN 15464, Vianello et al., GCN 15472) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2013/11 9.41 to 2013/11 9.53 UTC (13.06 to 16.11 hours after the LAT trigger), obtaining a total of 2.11 hours exposure in the r and i bands and 0.76 hours exposure in the Z, Y, J, and H bands. For a source within the enhanced XRT error circle (Stroh & Kennea, GCN 15474) , in comparison with the SDSS DR9 and 2MASS, we obtain the following detections: r 19.91 ± 0.02 i 19.70 ± 0.02 Z 19.57 ± 0.04 Y 19.23 ± 0.05 J 19.34 ± 0.07 H 19.09 ± 0.08 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We can confirm that this source fades during our observations with a power-law decay index of approximately -2. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15476 SUBJECT: GRB 131108A: Swift/UVOT Detection DATE: 13/11/09 16:54:16 GMT FROM: Margaret Chester at PSU M.M. Chester and M. C. Stroh (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of the Fermi/LAT-detected GRB 131108A 25920 s after the LAT trigger (Racusin et al., GCN Circ. 15464). A source consistent with the XRT position (Stroh and Kennea GCN Circ. 15474) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 10:26:00.45 = 156.50187 (deg.) Dec (J2000) = +09:39:44.1 = 9.66225 (deg.) with an estimated uncertainty of 0.58 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 27746 28046 295 19.70 +/- 0.10 b 26833 27133 295 19.67 +/- 0.16 u 25920 26220 295 19.10 +/- 0.14 w1 31699 32599 886 20.96 +/- 0.33 m2 37465 37914 442 >20.6 w2 45446 49794 1069 >21.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.028 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15477 SUBJECT: GRB 131108A: Fermi GBM observation DATE: 13/11/09 17:50:57 GMT FROM: George A. Younes at USRA/NASA/MSFC G. Younes (USRA/NASA-MSFC) reports on behalf of the Fermi GBM Team: At 20:41:55.76 UT on 08 November 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 131108A (trigger 405636118/131108862), which also triggered onboard the Fermi/LAT (Racusin et al, GCN 15464). The GBM on-ground location is consistent with the Swift/XRT location of the candidate afterglow (M. C. Stroh and J. A. Kennea, GCN 15468). The burst was bright enough that it also resulted in an Autonomous Repoint Request (ARR). The GBM light curve consists of a multiple-peak structure with a duration (T90) of about 19 s (50-300 keV). The time-averaged spectrum from T0 to T0+21 s is adequately fit by a Band function with Epeak = 373 +/- 14 keV, alpha = -0.91 +/- 0.02, and beta = -2.6 +/- 0.1. The event fluence (10-1000 keV) in this time interval is (3.65 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.1 s in the 10-1000 keV band is 19.8 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15478 SUBJECT: GRB 131108A: CARMA 3mm detection DATE: 13/11/09 19:27:44 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech) reports on behalf of a larger collaboration: We observed the position of Fermi GRB 131108A (Racusin et al., GCN 15464) with the Combined Array for Research in Millimeter Astronomy at a frequency of 93 GHz (3mm) starting at 13:26 UT on 2013-11-09, 16.7 hours after the burst. Observations continued until 14:55 UT (midpoint t=17.5 hours.) A source is detected at a position consistent with the location of X-ray (Stroh & Kennea, GCN 15468) and optical (Xu et al., GCN 15471) afterglows at a flux of approximately ~2 mJy. Follow-up observations are planned. We thank the CARMA staff for their support in executing these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15479 SUBJECT: GRB 131108A: AGILE/GRID observation DATE: 13/11/09 21:41:41 GMT FROM: Andrea Giuliani at IASF/INAF A. Giuliani (INAF/IASF-Mi), F. Longo (University of Trieste and INFN Trieste), F. Verrecchia, C. Pittori (ASDC and INAF/OAR), M. Marisaldi, F. Fuschino (INAF/IASF-Bo), F. Lucarelli (ASDC and INAF/OAR), E. Del Monte, F. Lazzarotto, I. Donnarumma, Y. Evangelista, M. Feroci, L. Pacciani, P. Soffitta, E. Costa, I. Lapshov, M. Rapisarda (INAF/IAPS Rome), G. Barbiellini, (INFN Trieste), A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, V. Fioretti, M. Galli (INAF/IASF-Bo), A. Chen, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF-Mi), M. Cardillo, E. Striani, M. Tavani (INAF/IAPS Rome, and Univ. Roma Tor Vergata), A. Argan, G. Piano, S. Sabatini, V. Vittorini (INAF/IAPS Rome), G. Pucella (ENEA Frascati), A. Pellizzoni, A. Trois (INAF/OA Cagliari), M. Pilia (ASTRON), S. Vercellone (INAF/IASF-Pa), P. W. Cattaneo, A. Rappoldi (INFN Pavia), A. Morselli, P. Picozza (INFN Roma-2), M. Prest, E. Vallazza (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), P. Giommi (ASI), and G. Valentini (ASI), on behalf of the AGILE Team, report: GRB 131108A (GCN 15464) transited in the field of view of AGILE approximately between t0-20 and t0+150 sec (with t0 = 08:41:55 UT). A preliminary analysis of the Gamma-Ray Imaging Detector (GRID) data in temporal and spatial coincidence with the GRB shows a significant excess of gamma-ray events above 30 MeV at the location of the event. During the first 80 seconds after t0 the GRID instrument detected 66 photons compatible with the GRB, most of which below 100 MeV, corresponding to a fluence of 2.56 +- 0.32 1e-5 erg / cm^2 in the energy band 30 MeV - 1 GeV. The energy distribution of photons in the same energy band is compatible with a power-law of index -2.35 +-0.2 . An analysis of the AGILE/MCAL data is also in progress. More observations of this interesting burst are strongly encouraged. This message may be cited. [GCN OPS NOTE(09nov13): This was delayed by ~1 hour because the submitor's new account had to added to the Circulars list.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15480 SUBJECT: Konus-Wind observation of GRB 131108A DATE: 13/11/10 12:05:37 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long-duration, bright, hard-spectrum GRB 131108A (Fermi-LAT detection: Racusin, et al., GCN 15464; Vianello, et al., GCN 15472; IPN triangulation: Hurley at al., GCN 15466; Fermi-GBM observation: Younes, GCN 15477; AGILE/GRID observation: Giuliani, et al., GCN 15479) triggered Konus-Wind at T0=74512.947 s UT (20:41:52.947). The light curve shows a mult-peaked structure from ~T0 to ~T0+20 s. The emission is seen up to ~12 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB131108_T74512/ As observed by Konus-Wind, the burst had a fluence of (4.15 ± 0.25)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0, of (2.10 ± 0.15)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum (measured from T0 to T0+23.04 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -1.11 ± 0.05, the high energy photon index beta = -2.72 ± 0.06, the peak energy Ep = 340 ± 11 keV, chi2 = 69.2/95 dof. The spectrum of the brightest initial spike (measured from T0 to T0+0.256 s) is best fit in the 50 keV - 15 MeV range by the cutoff power law with the following model parameters: the photon index alpha = -1.21 ± 0.11, and the peak energy Ep = 1326 ± 382 keV, chi2 = 52.9/70 dof. Assuming the redshift z=2.40 (de Ugarte Postigo, et al., GCN 15470; Xu, et al., GCN 15471), and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, and Omega_Lambda = 0.73, we estimate the following rest-frame parameters: the isotropic energy release E_iso is (5.8 ± 0.4)x10^53 erg, the peak luminosity L_iso is (1.0 ± 0.07)x10^54 erg/s, and the rest-frame peak energy Ep,i = (1160 ± 40) keV All the quoted results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15482 SUBJECT: GRB 131108A: Continued RATIR Optical and NIR Observations DATE: 13/11/11 18:15:07 GMT FROM: Eleonora Troja at GSFC Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of GRB 131108A (Racusin et al., GCN 15464, Vianello et al., GCN 15472 ) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2013/11 11.40 to 2013/11 11.53 UTC (61.01 to 64.03 hours after the LAT trigger), obtaining a total of 2.04 hours exposure in the r and i bands and 0.89 hours exposure in the Z, Y, J, and H bands. We continue to detect the previously reported source (Troja et al., GCN 15475). In comparison with the SDSS DR9 and 2MASS, we obtain the following detections and upper limits (3-sigma): r 22.4 ± 0.12 i 22.03 ± 0.11 Z 21.95 ± 0.22 Y 21.6 ± 0.3 J > 21.5 H > 21.0 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. A comparison with our earlier observations suggests a decay index of approximately -1.6 between our observations of 2013 Nov 9 and these observations. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15484 SUBJECT: GRB 131108A: optical observations DATE: 13/11/14 06:19:25 GMT FROM: Alina Volnova at SAI MSU A. Volnova (IKI), Yu. Krugly (IA KhNU), R. Inasaridze (AAO), I. Slyusarev (IA KhNU), G. Inasaridze (AAO), V. Zhuzhunadze (AAO), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of Swift GRB 131108A (Racusin et al., GCN 15464, Hurley et al. GCN 15466) with AZT-8 telescope of Institute of Astronomy, Kharkiv National University and with AS-32 telescope of Abastumani Observatory. We obtained several images in R-filter and also non-fileterd images. Within the enhanced XRT circle (Stroth & Kennea, GCN 15474) we detect the optical counterpart reported by Gorosabel et al. (GCN 15469). The details of preliminary photometry are following: UT start t-T0 Filter Exp. OT (mid, days) (s) 2013-11-10T02:00:12 1.24560 R 15x300 20.92 +/- 0.12 2013-11-11T00:44:00 2.21609 None 36x120 21.20 +/- 0.11 The photometry is based the SDSS stars, R magnitude (gri -> R transformations by Lupton 2005): SDSS id R J102559.54+093904.1 16.928 +/- 0.014 J102609.18+093958.8 17.999 +/- 0.021 J102610.10+093859.6 17.339 +/- 0.014 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15485 SUBJECT: GRB 131108A: ISON Blagoveshensk upper limit DATE: 13/11/14 06:21:44 GMT FROM: Alina Volnova at SAI MSU A. Volnova (IKI), D. Varda (ISON), E. Sinyakov (ISON), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 131108A (Racusin et al., GCN 15464, Hurley et al., GCN 15466) with ORI-25 telescope of ISON-Blagoveshensk observatory starting Nov., 9 (UT) 16:40:45. We took several unfiltered images with exposures of 30 seconds. In the combined images in the enhanced XRT circle (Stroth & Kennea, GCN 15474) we do not detect the OT reported by Gorosabel et al. (GCN 15469). The details of the photometry are the following: UT start t-T0 Filter Exp. OT UL (3sigma) (mid, days) (s) 16:40:45 0.85072 None 95x30 n/d 17.1 The photometry is based on a nearby bright SDSS star, R (gri -> R transformations by Lupton 2005): SDSS id R J102613.43+094109.5 13.318 +/- 0.013 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15502 SUBJECT: GRB 131108A: VLA Observations DATE: 13/11/19 04:01:15 GMT FROM: S. Bradley Cenko at Caltech A. Corsi (GWU), S. B. Cenko (NASA/GSFC), and D. A. Perley (Caltech) report on behalf of a larger collaboration: We imaged the position of the Fermi-LAT GRB 131108A (Racusin et al., GCN 15464) with the Very Large Array in the 18.7-24.9 GHz frequency range, starting at about 2.6 days after the burst. A provisional reduction shows a source consistent with the location of the X-ray (Stroh and Kennea, GCN 15468) and optical (e.g., Xu et al., GCN 15471) afterglow. At this time, we estimate a preliminary flux of about 200 uJy at 19 GHz. Further observations are planned. We thank the VLA staff for their support.