//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15446 SUBJECT: GRB 131105A: Swift detection of a burst DATE: 13/11/05 02:17:27 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), A. Y. Lien (NASA/GSFC/ORAU), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 02:04:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 131105A (trigger=576738). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 71.011, -62.981 which is RA(J2000) = 04h 44m 03s Dec(J2000) = -62d 58' 52" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multple peaks with a total duration of about 120 sec. The peak count rate was ~1100 counts/sec (15-350 keV), at ~44 sec after the trigger. The XRT began observing the field at 02:09:35.6 UT, 290.9 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 70.96452, -62.99394 which is equivalent to: RA(J2000) = 04h 43m 51.48s Dec(J2000) = -62d 59' 38.2" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 89 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (2.91 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 2.2 (+2.11/-1.84) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 294 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 5% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15447 SUBJECT: GRB 131105A: VLT/X-shooter optical afterglow candidate DATE: 13/11/05 04:20:01 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), D. Malesani (DARK/NBI), N. R. Tanvir (U. Leicester), T. Kruehler (ESO), report on behalf of a larger collaboration: We observed the field of GRB 131105A (Cummings et al., GCN 15446) with the acquisition camera of the X-shooter spectrograph at the VLT. The observation was taken around 03:24 UT on November 5, that is 1.3 hr after the GRB. Inside the current XRT error circle (2.0" radius; see http://www.swift.ac.uk/xrt_positions/), we detect a single source at coordinates (J2000): RA = 04:43:52.27 Dec = -62:59:43.7 with an uncertainty of <0.5". Its magnitude is R = 22.4 +- 0.1, compared to three nearby bright USNO stars. At the moment we cannot conclude whether this source is variable or associated to the GRB, but we propose it as a candidate counterpart. We acknowledge excellent support from the ESO staff in Paranal, in particular Dimitri Gadotti and Roger Wesson. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15448 SUBJECT: GRB 131105A: Enhanced Swift-XRT position DATE: 13/11/05 07:15:56 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 704 s of XRT Photon Counting mode data and 1 UVOT images for GRB 131105A, 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 = 70.96782, -62.99505 which is equivalent to: RA (J2000): 04h 43m 52.28s Dec (J2000): -62d 59' 42.2" with an uncertainty of 1.8 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15449 SUBJECT: GRB 131105A: TAROT La Silla observatory optical observations DATE: 13/11/05 07:32:49 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A., Turpin D. (IRAP-CNRS-OMP), 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 131105A detected by SWIFT (trigger 576738) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 231s after the GRB trigger (14s after the notice). The elevation of the field increased from 37 degrees above horizon and weather conditions were good. A first series of 30.0s exposure images was acquired in tracking mode. We do not detect the afterglow candidate of Xu et al. (GCNC 15447) with limiting magnitudes of: t0+231s to t0+261s : Rlim = 18.3 t0+311s to t0+341s : Rlim = 18.3 t0+351s to t0+381s : Rlim = 18.3 t0+391s to t0+421s : Rlim = 18.3 t0+432s to t0+462s : Rlim = 18.3 Next series were co added by drizzling to increase the detectivity. t0+ 472s to t0+1131s : Rlim = 19.0 t0+1141s to t0+1658s : Rlim = 19.0 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: 15450 SUBJECT: GRB 131105A: VLT/X-shooter redshift DATE: 13/11/05 09:48:07 GMT FROM: Nial Tanvir at U.Leicester D. Xu, D. Malesani (DARK/NBI), N. Tanvir (U. Leicester), T. Kruehler (ESO), J. Fynbo (DARK/NBI) report on behalf of the X-shooter GRB collaboration: We have obtained spectroscopic observations of the afterglow of GRB 131105A (Cummings et al., GCN 15446; Xu et al., GCN 15447), beginning at 03:46 UT, approximately 102 minutes post-trigger. We used the ESO VLT equipped with the X-shooter spectrograph, covering the wavelength range 3000-20000 AA. The exposure time was 8x600 s. In the NIR arm, we detect two emission lines, interpreted as [O III] (5007) and H-alpha at a common redshift z = 1.686. In the spectrum we also detect absorption lines at the same redshift, albeit at low signal-to-noise ratio. Furthermore, we measure significant fading of the source between two sets of acquisition images, confirming that we are seeing afterglow and host light. Hence, we consider z = 1.686 the likely redshift of GRB 131105A. The afterglow appears to be red presumably due to dust extinction. We acknowledge excellent support from the observing staff at Paranal, in particular Dimitri Gadotti, Roger Wesson, and Claudia Reyes. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15452 SUBJECT: Konus-Wind observation of GRB 131105A DATE: 13/11/05 11:18:56 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 GRB 131105A (Swift-BAT trigger 576738: Cummings et al., GCN 15446) triggered Konus-Wind at T0=7527.233 s UT (02:05:27.233). The burst light curve shows multiple peaks in the time interval from ~T0-35 s till ~T0+90 s. The emission is seen up to ~3 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB131105_T07527/ As observed by Konus-Wind, the burst had a fluence of (2.3 ± 0.2)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.600 s, of (2.0 ± 0.2)x10-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum (measured from T0 to T0+90.368 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 = -0.88 ± 0.38, the high energy photon index beta = -2.33 ± 0.33, the peak energy Ep = 156 ± 38 keV, chi2 = 97/96 dof. The spectrum near the maximum count rate (measured from T0 to T0+8.448 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 = -1.04 ± 0.27, the high energy photon index beta = -2.64 ± 0.76, the peak energy Ep = 174 ± 41 keV, chi2 = 87.9/97 dof. Assuming the redshift z=1.686 (Xu, et al., GCN 15450) 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 (1.7 ± 0.1)x10^53 erg, the peak luminosity L_iso is (4.0 ± 0.4)x10^52 erg/s, and the rest-frame peak energy Ep,i = (420 ± 100) keV All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15454 SUBJECT: GRB 131105A: Swift/UVOT Upper Limits DATE: 13/11/05 11:40:36 GMT FROM: Massimiliano de Pasquale at MSSL-UCL M. De Pasquale (UCL-MSSL) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 131105A 295 s after the BAT trigger (Cummings et al., GCN Circ. 15446). No optical afterglow consistent with the optical position (Xu et al. GCN Circ. 15447) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 295 444 147 >21.5 white 295 1544 353 >22.0 v 774 1594 97 >19.3 b 1152 1520 58 >19.9 u 848 1495 78 >19.8 w1 823 1471 78 >19.4 m2 798 1619 39 >18.4 w2 750 1570 78 >19.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15455 SUBJECT: GRB 131105A: Fermi GBM observation DATE: 13/11/05 16:18:25 GMT FROM: Gerard Fitzpatrick at UCD G. Fitzpatrick (UCD) and P. Jenke (UAH) report on behalf of the Fermi GBM Team: At 02:04:53.49 UT on 05 November 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 131105A (trigger 405309896/131105087), which was also detected by Swift (Cummings et al., GCN 15446) and Konus-Wind (Golenetskii et al, GCN 15452). The GBM on-ground location is consistent with the Swift/XRT position (Osborne et al., GCN 15448). The angle from the Fermi LAT boresight is 37 degrees. The GBM light curve consists of a multiple-peak structure with a duration (T90) of about 112 s (50-300 keV). The time-averaged spectrum from T0-3 s to T0+121 s is adequately fit by a Band function with Epeak = 203.9 +/- 31.1 keV, alpha = -1.2 +/- 0.1, and beta = -1.8 +/- 0.1. The event fluence (10-1000 keV) in this time interval is (2.9 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+108 s in the 10-1000 keV band is 8.4 +/- 0.3 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: 15458 SUBJECT: GRB 131105A: Swift-XRT refined Analysis DATE: 13/11/05 17:17:04 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), V. Mangano (PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), M.C. Stroh (PSU) and J.R. Cummings report on behalf of the Swift-XRT team: We have analysed 8.3 ks of XRT data for GRB 131105A (Cummings et al. GCN Circ. 15446), from 276 s to 36.2 ks after the BAT trigger. The data comprise 7 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 15448). The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=8.0 (+0.0, -1.5). At T+353 s the decay flattens to an alpha of 0.62 (+/-0.04) before breaking again at T+21.4 ks to a final decay with index alpha=2.3 (+0.9, -0.8). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.22 (+0.16, -0.15). The best-fitting absorption column is 2.2 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 2.9 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 3.5 x 10^-11 (5.9 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.2 (+0.5, -0.4) x 10^21 cm^-2 Galactic foreground: 2.9 x 10^20 cm^-2 Excess significance: 7.5 sigma Photon index: 2.22 (+0.16, -0.15) If the light curve continues to decay with a power-law decay index of 2.3, the count rate at T+24 hours will be 3.4 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-13 (2.0 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/00576738. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15459 SUBJECT: GRB 131105A, Swift-BAT refined analysis DATE: 13/11/06 03:02:25 GMT FROM: Amy Lien at GSFC W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), F. E. Marshall (NASA/GSFC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 131105A (trigger #576738) (Cummings, et al., GCN Circ. 15446). The BAT ground-calculated position is RA, Dec = 70.973, -63.005 deg which is RA(J2000) = 04h 43m 53.5s Dec(J2000) = -63d 00' 17.7" with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 7%. The mask-weighted light curve shows a multi-peak structure starts at ~T+0 sec and ends at ~T+126 sec. The light curve consists of ~ 5 obvious peaks. T90 (15-350 keV) is 112.3 +- 4.1 sec (estimated error including systematics). The time-averaged spectrum from T+6.8 to T+125.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.45 +- 0.11. The fluence in the 15-150 keV band is 7.1 +- 0.5 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+116.64 sec in the 15-150 keV band is 3.5 +- 0.6 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/576738/BA/