//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18398 SUBJECT: GRB 151006A: Swift detection of a burst DATE: 15/10/06 10:05:37 GMT FROM: Scott Barthelmy at NASA/GSFC D. Kocevski (NASA/GSFC/ORAU), S. D. Barthelmy (GSFC), P. A. Evans (U Leicester), K. L. Page (U Leicester) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 09:55:01 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 151006A (trigger=657750). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 147.451, +70.509, which is RA(J2000) = 09h 49m 48s Dec(J2000) = +70d 30' 31" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single FRED-like peak structure with a duration of about 40 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 09:55:50.4 UT, 48.6 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 147.4256, 70.5036 which is equivalent to: RA(J2000) = +09h 49m 42.14s Dec(J2000) = +70d 30' 13.0" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 36 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 150 seconds with the White filter starting 58 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 100% of the XRT 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 XRT 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 0.24. Burst Advocate for this burst is D. Kocevski (dankocevski AT gmail.com). 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: 18399 SUBJECT: GRB 151006A: Prompt enhanced Swift-XRT position DATE: 15/10/06 10:23:24 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Using promptly downlinked XRT event data for GRB 151006A, we find an enhanced XRT position of the afterglow: RA, Dec: 147.4260, 70.5027 which is equivalent to: RA (J2000) = 09 49 42.25 Dec (J2000) = +70 30 09.7 with an uncertainty of 2.3 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/657750. Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18400 SUBJECT: GRB 151006A: Kanata/HOWPol optical imaging polarimetry DATE: 15/10/06 11:05:12 GMT FROM: Koji Kawabata at HASC,Hiroshima U K. S. Kawabata, R. Itoh, M. Kawabata, T. Nakaoka, H. Mori, K. Takaki (Hiroshima Univ.), and R. Shimotani (Kagawa Univ.) report on behalf of Kanata team: We performed a series of optical imaging-polarimetry for the optical afterglow of GRB151006A (Kocevski et al., GCN 18398) from 73 sec after the Swift/BAT trigger with HOWPol attached to the 1.5-m Kanata telescope at Higashi-Hiroshima Observatory, Japan. We could not detect any afterglow within the XRT error circle reported in the GCN 18398. We obtained the following preliminary upper limits in our first image (mid-time 88 sec after the trigger) calibrated with UCAC4: Rc > 17.7 Further analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18402 SUBJECT: GRB 151006A: MITSuME Okayama upper limits DATE: 15/10/06 11:52:48 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME and OISTER collaboration: We observed the field of GRB 151006A (Kocevski et al., GCNC 18398) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2015-10-06 09:56:35 UT (~93 sec after the burst). We did not find any new point source within the enhanced XRT error circle (Evans, GCNC 18399) in all the three bands. Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.00707 10:05:12 540.0 >18.6 >18.6 >18.0 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18403 SUBJECT: GRB 151006A: Enhanced Swift-XRT position DATE: 15/10/06 14:08:27 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 2266 s of XRT Photon Counting mode data and 5 UVOT images for GRB 151006A, 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 = 147.42592, +70.50299 which is equivalent to: RA (J2000): 09h 49m 42.22s Dec (J2000): +70d 30' 10.8" with an uncertainty of 1.7 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: 18404 SUBJECT: GRB 151006A: Fermi GBM detection DATE: 15/10/06 16:02:36 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) and C.Meegan (UAH) report on behalf of the Fermi GBM Team: "At 09:54:57.83 UT on 06 October 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 151006A (trigger 465818101/151006413), which was also detected by Swift BAT and XRT (Kocevski et al. 2015, GCN 18398). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time using the Swift position is 30 degrees. The GBM light curve consists of a FRED-like peak with a duration (T90) of about 84 s (50-300 keV). The time-averaged spectrum from T0+0 s to T0+83.7 s is best fit by a Band function with Epeak = 227 +/- 53 keV, alpha = -1.17 +/- 0.07, and beta = -1.68 +/- 0.04 The event fluence (10-1000 keV) in this time interval is (1.15 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+5.24 s in the 10-1000 keV band is 4.9 +/- 0.2 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: 18405 SUBJECT: GRB 151006A: Swift/UVOT Upper Limits DATE: 15/10/06 19:03:04 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and D. Kocevski (NASA/GSFC/ORAU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 151006A 36 s after the BAT trigger (Kocevski et al., GCN Circ. 18398). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 18403) 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 58 208 147 >20.7 u_FC 271 521 246 >19.9 white 58 6351 520 >21.4 v 36 6754 437 >19.8 b 527 6146 236 >20.3 u 271 5941 442 >20.3 w1 5537 5736 197 >19.8 m2 625 5531 235 >19.7 w2 577 6557 432 >20.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.24 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18406 SUBJECT: GRB 151006A: Fermi-LAT detection DATE: 15/10/06 21:13:33 GMT FROM: Daniel Kocevski at GSFC M. Ohno (Hiroshima U.), E. Bissaldi (INFN Bari), G. Vianello (Stanford University), D. Kocevski (NASA/GSFC) and F. Longo (University & INFN Trieste) report on behalf of the Fermi-LAT team: At 09:54:57.83 on October 06, 2015, Fermi-LAT detected high-energy emission from GRB 151006A, which was also detected by Fermi-GBM (trigger 465818101; Roberts et al. GCN 18404) and Swift-BAT (Kocevski et al. GCN 18398). The GBM location was initially inside the LAT field of view at an angle of ~30 degrees to the LAT boresight. Using the LAT Low Energy (LLE) data selection, over 400 counts above background were detected within a 30 s interval coinciding with the time of the GBM emission. This data selection has insufficient spatial resolution to provide a reliable LAT localization. Processing and analysis of standard data is 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: 18407 SUBJECT: GRB 151006A: Swift-XRT refined Analysis DATE: 15/10/06 22:05:02 GMT FROM: Phil Evans at U of Leicester L.M. McCauley (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU) and D. Kocevski report on behalf of the Swift-XRT team: We have analysed 11 ks of XRT data for GRB 151006A (Kocevski et al. GCN Circ. 18398), from 40 s to 29.1 ks after the BAT trigger. The data comprise 552 s in Windowed Timing (WT) mode (the first 7 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 18399). The light curve can be modelled with an initial power-law decay with an index of alpha=0.3 (+0.7, -1.6), followed by a break at T+64.1 s to an alpha of 1.377 (+0.020, -0.019). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.45 (+0.06, -0.05). The best-fitting absorption column is 4.9 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 7.7 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.08 (+0.17, -0.16) and a best-fitting absorption column of 4.3 (+0.9, -0.8) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (6.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 4.3 (+0.9, -0.8) x 10^21 cm^-2 Galactic foreground: 7.7 x 10^20 cm^-2 Excess significance: 7.1 sigma Photon index: 2.08 (+0.17, -0.16) If the light curve continues to decay with a power-law decay index of 1.377, the count rate at T+24 hours will be 4.7 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x 10^-13 (2.9 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/00657750. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18408 SUBJECT: GRB 151006A: MITSuME Okayama Ks-band upper-limit DATE: 15/10/07 02:58:46 GMT FROM: Kenshi Yanagisawa at OAO/NAOJ Kenshi Yanagisawa, Daisuke Kuroda, Yasuhiro Shimizu, Hideyuki Izumiura(OAO/NAOJ), Michitoshi Yoshida (Hiroshima-U), Kouji Ohta(Kyoto-U) and Nobuyuki Kawai(Tokyo Tech.) report on behalf of the MITSuME collaboration: We observed the field of GRB151006A (Kocevski et al., GCN 18398) in Ks-band with a wide-field near infrared imager at Okayama Astrophysical Observatory (Japan). The imager has effective aperture of 0.91 m. Observations started from 17:22 UT on 6th October, 7.4h after the BAT trigger, to 18:17 UT. The total exposure of 26.5 min was successfully obtained. In our co-add image, we did not find any new point source within the enhanced XRT error circle (Goad et al., GCN 18403) down to limiting magnitude of Ks=15.2 (Vega, S/N=10). The photometric calibration was made against 2MASS field stars. T0+[sec] MID-UT T-EXP[sec] Ks --------------------------------------------------- +26,819 17:49 1,590 >15.2 --------------------------------------------------- T0+ : Elapsed time after the burt [sec] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18409 SUBJECT: GRB 151006A: Swift-BAT refined analysis DATE: 15/10/07 15:19:37 GMT FROM: Amy Lien at GSFC J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), N. Gehrels (GSFC), D. Kocevski (NASA/GSFC/ORAU), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+800 sec from the recent telemetry downlink, we report further analysis of BAT GRB 151006A (trigger #657750) (Kocevski, et al., GCN Circ. 18398). The BAT ground-calculated position is RA, Dec = 147.426, 70.508 deg which is RA(J2000) = 09h 49m 42.3s Dec(J2000) = +70d 30' 30.2" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a FRED-like structure that starts at ~T-5 s, peaks at ~ T+1 s, and ends at ~ T+310 s. T90 (15-350 keV) is 203.9 +- 41.6 sec (estimated error including systematics). The time-averaged spectrum from T-4.9 to T+311.2 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.56 +- 0.06. The fluence in the 15-150 keV band is 6.9 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+1.49 sec in the 15-150 keV band is 2.6 +- 0.2 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/657750/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18410 SUBJECT: GRB 151006A: Swift-BAT refined analysis DATE: 15/10/07 15:40:03 GMT FROM: Amy Lien at GSFC J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), N. Gehrels (GSFC), D. Kocevski (NASA/GSFC/ORAU), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+800 sec from the recent telemetry downlink, we report further analysis of BAT GRB 151006A (trigger #657750) (Kocevski, et al., GCN Circ. 18398). The BAT ground-calculated position is RA, Dec = 147.426, 70.508 deg which is RA(J2000) = 09h 49m 42.3s Dec(J2000) = +70d 30' 30.2" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a FRED-like structure that starts at ~T-5 s, peaks at ~ T+1 s, and ends at ~ T+310 s. T90 (15-350 keV) is 203.9 +- 41.6 sec (estimated error including systematics). The time-averaged spectrum from T-4.9 to T+311.2 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.56 +- 0.06. The fluence in the 15-150 keV band is 6.9 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+1.49 sec in the 15-150 keV band is 2.6 +- 0.2 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/657750/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18411 SUBJECT: GRB 151006A: OSN optical upper limit DATE: 15/10/07 17:43:58 GMT FROM: Samantha Oates at MSSL S. R. Oates (IAA-CSIC), S. Jeong (IAA-CSIC/SKKU), A. Sota, J. C. Tello (IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC/UMA), S. B. Pandey (ARIES Nainital) report on behalf of a larger collaboration: We observed the field of GRB 151006A (Kocevski et al., GCN Circ. 18398) with the 1.5m OSN telescope at Observatorio de Sierra Nevada (Spain). The observations were carried out in the I band on Oct 7.13159-7.17369 (17.24 - 18.25 hours post bust). We do not detect any new optical source within the enhanced XRT error circle (Goad et al., GCN Circ. 18403) down to a limiting magnitude of I ~21mag. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18413 SUBJECT: Konus-Wind observation of GRB 151006A DATE: 15/10/08 11:04:52 GMT FROM: Anastasia Tsvetkova at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, A. Kozlova and T. Cline on behalf of the Konus-Wind team, report: The long-duration, hard-spectrum GRB 151006A (Swift-BAT trigger #657750: Kocevski et al., GCN 18398; Cummings et al., GCN 18409; Fermi GBM detection: Roberts & Meegan, GCN 18404) triggered Konus-Wind at T0=35697.746 s UT (09:54:57.746). The burst light curve shows a single FRED-like pulse with a total duration of ~114 s. The emission is seen up to ~10 MeV. As observed by Konus-Wind, the burst had a fluence of 5.30(-0.87,+0.92)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0+2.928 s, of 5.60(-2.26,+2.23)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+73.984 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -1.26(-0.23,+0.42), the high energy photon index beta = -1.73(-0.13,+0.09), the peak energy Ep = 223(-132,+514) keV, chi2 = 85/97 dof. The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.40(-0.06,+0.07), and Ep = 2600(-1200,+2900) keV (chi2 = 71/98 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -1.7 (chi2 = 71/97 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB151006_T35697/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18415 SUBJECT: GRB 151006A: MITSuME Akeno optical upper limits DATE: 15/10/09 13:37:39 GMT FROM: Taketoshi Yoshii at Tokyo Tech S.Harita, T.Fujiwara, T. Yoshii, Y. Saito, Y. Tachibana, H. Ohuchi, Y. Yano, S. Kurita, Y.Ono, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We searched for the optical counterpart of GRB 151006A (D. Kocevski et al. GCN Circular #18398) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2015-10-06 15:20:15 UT (~4.4 h after the burst). We did not find any new point source within XRT circle in all three bands. We obtained following limits for the magnitudes. T0+[sec] MID-UT T-EXP[sec] g' Rc Ic --------------------------------------------------------------------------------------- 19514 17:24:12.2 9240 >21.3 >20.8 > 19.9 --------------------------------------------------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18416 SUBJECT: GRB 151006A: Mondy optical upper limit DATE: 15/10/11 10:03:30 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of Swift GRB 151006A (Kocevski et al., GCN 18398) with AZT-33IK telescope of Sayan observatory (Mondy) starting on Oct. 18 (UT) 16:50:47. We obtained several images in R-filter of 120 s exposure. Within XRT error circle (Goad et al., GCN 18403) we do not detect any optical source. Upper limit is following Date UT start t-T0 Filter Exp. UL (3 sigma) (mid, days) (s) 2015-10-06 16:50:47 0.31306 R 35*120 22.4 Photometry is based on USNO-B1.0 stars: USNO-B1.0_id R2 1604-0085829 18.23 1604-0085812 16.90 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18422 SUBJECT: GRB 151006A: Astrosat CZTI detection DATE: 15/10/16 11:28:09 GMT FROM: Varun Bhalerao at IUCAA V. Bhalerao (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration: Analysis of Astrosat commissioning data showed the presence of GRB 151006A (Kocevski et al. 2015, GCN 18398) in the Cadmium Zinc Telluride Imager. The source was located 60.7 degrees away from the pointing direction and was detected at energies above 60 keV. Modelling the profile as a fast rise and exponential decay, we measure T90 of 65s, 75s, and 50s in 60-80 keV, 80-100 keV and 100-250 keV bands respectively. In addition, the GRB is clearly detected in a lightcurve created from double events satisfying Compton scattering criteria (Vadawale et al., 2015, A&A, 578, 73). This demonstrates the feasibility of measuring polarisation for brighter GRBs with CZTI. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18475 SUBJECT: GRB 151006A: CALET Gamma-Ray Burst Monitor detection DATE: 15/10/27 00:49:24 GMT FROM: Takanori Sakamoto at AGU A. Yoshida, T. Sakamoto, I. Takahashi, Y. Kawakubo, K. Senuma, M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), M. L. Cherry (LSU), S. Ricciarini (U of Florence) and the CALET collaboration: The long-duration GRB 151006A (Kocevski et al., GCN Circ. 18398; Cummings et al., GCN Circ. 18409; Roberts & Meegan, GCN Circ. 18404; Golenetskii et al., GCN Circ. 18413; Bhalerao et al., GCN Circ. 18422) triggered the CALET Gamma-Ray Burst Monitor (CGBM) at 09:54:59.97 UT on 6 October 2015. The clear burst signal was detected by the Soft Gamma-ray Monitor (SGM; 30 keV - 20 MeV) which is a scintillation detector utilized a BGO crystal. Due to a large incident angle of the event, no signal was detected by the Hard X-ray Monitor (HXM; 7 keV - 1 MeV) which is a scintillation detector composed of a LaBr3(Ce) crystal. The SGM light curve shows two spikes peaking at T0-2s and T0+2s, and the emission ending around T0+~60s. The T90 duration measured by the SGM data is 63 +- 5 s (30 - 1000 keV). Currently, CALET is in the commissioning phase. Further information about CALET and CGBM can be found at http://calet.jp/en/ and http://www.en.yoshida-agu.net/research/calet-gbm