//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21976 SUBJECT: GRB 171007A: Swift detection of a burst DATE: 17/10/07 12:14:34 GMT FROM: Kim Page at U.of Leicester J. K. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 11:57:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 171007A (trigger=777215). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 135.544, +42.849, which is RA(J2000) = 09h 02m 10s Dec(J2000) = +42d 50' 57" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several peaks with a total duration of about 25 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 11:58:47.2 UT, 68.9 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 135.6006, 42.8195 which is equivalent to: RA(J2000) = 09h 02m 24.15s Dec(J2000) = +42d 49' 10.3" with an uncertainty of 2.3 arcseconds (radius, 90% containment). This location is 183 arcseconds from the BAT onboard position, at the edge of 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 consistent with the Galactic value of 2.05 x 10^20 cm^-2 (Willingale et al. 2013). The initial flux in the 2.5 s image was 6.22e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 77 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 0.02. Burst Advocate for this burst is J. K. Cannizzo (cannizzo 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: 21977 SUBJECT: GRB 171007A: RATIR Optical and NIR Observations DATE: 17/10/07 14:39:05 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 171007A (Cannizzo, et al., GCN 21976) 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 2017/10 7.50 to 2017/10 7.52 UTC (3 minutes to 0.57 hours after the BAT trigger), obtaining a total of 0.31 hours exposure in the r and i bands and 0.14 hours exposure in the Z, Y, J, and H bands. For a source within the Swift-XRT error circle, in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following upper limits (3-sigma): r > 22.05 i > 21.94 Z > 21.24 Y > 21.02 J > 20.65 H > 20.34 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21978 SUBJECT: GRB 171007A: Swift-XRT refined Analysis DATE: 17/10/07 17:55:02 GMT FROM: Phil Evans at U of Leicester V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester) and J.K. Cannizzo report on behalf of the Swift-XRT team: We have analysed 6.1 ks of XRT data for GRB 171007A (Cannizzo et al. GCN Circ. 21976), from 62 s to 12.7 ks after the BAT trigger. The data comprise 107 s in Windowed Timing (WT) mode (the first 5 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The best available XRT position (using the promptly downlinked event data, the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) is RA, Dec = 135.6008, 42.8193 which is equivalent to: RA (J2000): 09 02 24.19 Dec(J2000): +42 49 09.5 with an uncertainty of 2.3 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=3.56 (+0.21, -0.18). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.38 (+0.19, -0.18). The best-fitting absorption column is 1.2 (+0.9, -0.7) x 10^21 cm^-2, in excess of the Galactic value of 2.1 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.7 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 1.2 (+0.9, -0.7) x 10^21 cm^-2 Galactic foreground: 2.1 x 10^20 cm^-2 Excess significance: 2.4 sigma Photon index: 1.38 (+0.19, -0.18) If the light curve continues to decay with a power-law decay index of 3.56, the count rate at T+24 hours will be 1.1 x 10^-10 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.2 x 10^-21 (5.7 x 10^-21) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00777215. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21979 SUBJECT: GRB 171007A: Enhanced Swift-XRT position DATE: 17/10/07 18:09:49 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 1637 s of XRT Photon Counting mode data and 2 UVOT images for GRB 171007A, 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 = 135.60048, +42.81920 which is equivalent to: RA (J2000): 09h 02m 24.11s Dec (J2000): +42d 49' 09.1" with an uncertainty of 2.0 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: 21980 SUBJECT: GRB 171007A: Fermi GBM observation DATE: 17/10/07 22:45:12 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP Elisabetta Bissaldi (Politecnico & INFN Bari) reports on behalf of the Fermi GBM Team: "At 11:57:39.90 UT on 07 October 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 171007A (trigger 529070264 / 171007498), which was also detected by the Swift-BAT (Cannizzo et al. 2017, GCN 21976). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 50 degrees. The GBM light curve consists of single peak with a duration (T90) of about 3.5 s (50-300 keV). The time-averaged spectrum from T0-1.4 s to T0+2.1 s is adequately fit by a simple power law function with index -1.31 +/- 0.07. The event fluence (10-1000 keV) in this time interval is (6.1 +/- 0.7)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-1 s in the 10-1000 keV band is 1.5 +/- 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: 21981 SUBJECT: GRB 171007A: Swift-BAT refined analysis DATE: 17/10/08 16:57:32 GMT FROM: Amy Lien at GSFC S. D. Barthelmy (GSFC), J. K. Cannizzo (NASA/UMBC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), J. P. Norris (BSU), 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+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 171007A (trigger #777215) (Cannizzo et al., GCN Circ. 21976). The BAT ground-calculated position is RA, Dec = 135.635, 42.930 deg which is RA(J2000) = 09h 02m 32.5s Dec(J2000) = +42d 55' 47.4" with an uncertainty of 3.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a short spike that start at ~ T-0.1 s and ends at ~ T+2.9 s. There is some weak emission lasting till ~T+80 s. T90 (15-350 keV) is 105 +- 45 sec (estimated error including systematics). The time-averaged spectrum from T-0.08 to T+107.92 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.38 +- 0.52. The fluence in the 15-150 keV band is 2.9 +- 1.1 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.92 sec in the 15-150 keV band is 0.4 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. Although the burst is weak and the short spike is ~ 3 s, the structure of the burst shows similarity to those of short GRBs with extended emission. We thus perform further analysis on the short spike and the tail emission. The spectrum of the short spike from T-0.08 to T+2.92 sec is best fit by a simple power-law model, with power-law index of 0.83 +- 0.35 and fluence (15-150 keV) of 1.0 +- 0.2 x 10^-7 erg/cm2. The spectrum of the tail emission from T+2.92 to T+107.92 sec is best fit by a simple power-law model, with power-law index of 1.67 +- 0.73 and fluence (15-150 keV) of 1.8 +- 1.0 x 10^-7 erg/cm2. These values are consistent with those of short GRBs with extended emission (Lien & Sakamoto et al. 2016). The lag analysis is unconstrained due to the weakness of this burst. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/777215/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21984 SUBJECT: GRB 171007A: Swift/UVOT Upper Limits DATE: 17/10/10 16:42:31 GMT FROM: Frank Marshall at GSFC F. E. Marshall (NASA/GSFC) and J. K. Cannizzo (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 171007A 77 s after the BAT trigger (Cannizzo et al., GCN Circ. 21976). No optical afterglow consistent with the enhanced XRT position (Beardmore et al. GCN Circ. 21979) 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 77 227 147 >20.7 u_FC 291 540 246 >20.4 white 77 6966 805 >21.7 v 620 7377 529 >19.5 b 546 6761 510 >20.8 u 291 6556 559 >20.7 w1 669 6351 333 >20.3 m2 644 7572 480 >19.9 w2 596 7172 529 >20.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).