//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16819 SUBJECT: GRB 140916A: Swift detection of a burst DATE: 14/09/16 10:58:29 GMT FROM: Judith Racusin at GSFC J. L. Racusin (NASA/GSFC), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), D. Malesani (DARK/NBI) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 10:43:47 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140916A (trigger=612804). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 40.405, -39.711 which is RA(J2000) = 02h 41m 37s Dec(J2000) = -39d 42' 38" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is an image trigger so details of the lightcurve can not yet be determined. The XRT began observing the field at 10:46:18.3 UT, 150.8 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 40.39910, -39.68686 which is equivalent to: RA(J2000) = 02h 41m 35.78s Dec(J2000) = -39d 41' 12.7" with an uncertainty of 3.8 arcseconds (radius, 90% containment). This location is 87 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. No spectrum from the promptly downlinked event data is yet available to determine the column density. The initial flux in the 2.5 s image was 1.26e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 160 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 0.01. Burst Advocate for this burst is J. L. Racusin (judith.racusin AT 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: 16820 SUBJECT: GRB 140916A: Prompt enhanced Swift-XRT position DATE: 14/09/16 11:25:31 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 140916A, we find an enhanced XRT position of the afterglow: RA, Dec: 40.3999, -39.6865 which is equivalent to: RA (J2000) = 02 41 35.98 Dec (J2000) = -39 41 11.4 with an uncertainty of 2.0 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/612804. 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: 16821 SUBJECT: GRB 140916A: FTS observations DATE: 14/09/16 16:06:06 GMT FROM: Simone Dichiara at Ferrara U/Italy S. Dichiara, C. Guidorzi (U. Ferrara), J. Japelj (U. Ljubljana) on behalf of a large collaboration report: The 2-m Faulkes Telescope South in Siding Spring (Australia) began observing Swift GRB 140916A (Racusin et al. GCN Circ 16819) on September 16 at 11:52:12 UT, i.e. ~1.14 hours after the BAT trigger, with the r' and i' filters. Within the enhanced XRT error circle (Evans et al. GCN Circ. 16820) we find no optical counterpart to the following limiting magnitude: Mid time from Total Exp Filter Magnitude trigger (hr) (s) ------------------------------------------------- 1.26 60x7 r' > 20.4 1.44 60x5 i' > 18.7 ------------------------------------------------- Magnitudes are calibrated against nearby USNO-B1 stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16823 SUBJECT: GRB 140916A: MITSuME Okayama upper limits DATE: 14/09/16 19:38:44 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 140916A (Racusin et al., GCNC 16819) 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 2014-09-16 17:07:26 UT, (~6.4 h after the burst). We did not find any new point source within the enhanced XRT circle (Evans, GCNC 16820) 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 ----------------------------------------------------- 0.30614 18:04:37 3840.0 >18.9 >19.5 >18.7 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16824 SUBJECT: GRB 140916A: Enhanced Swift-XRT position DATE: 14/09/16 22:39:06 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 8554 s of XRT Photon Counting mode data and 10 UVOT images for GRB 140916A, 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 = 40.39949, -39.68645 which is equivalent to: RA (J2000): 02h 41m 35.88s Dec (J2000): -39d 41' 11.2" with an uncertainty of 1.4 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: 16825 SUBJECT: GRB 140916A: Swift-XRT refined Analysis DATE: 14/09/16 22:58:06 GMT FROM: Phil Evans at U of Leicester B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), V. Mangano (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and J.L. Racusin report on behalf of the Swift-XRT team: We have analysed 13 ks of XRT data for GRB 140916A (Racusin et al. GCN Circ. 16819), from 141 s to 30.7 ks after the BAT trigger. The data comprise 218 s in Windowed Timing (WT) mode (the first 8 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 Osborne et al. (GCN Circ. 16820). The late-time light curve (from T0+5.3 ks) is consistent with a constant source of mean count rate 5.4e-01 ct/sec. A power-law fit gives an index of -0.04 (+/-0.08). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.70 (+/-0.11). The best-fitting absorption column is 1.51 (+0.24, -0.23) x 10^21 cm^-2, in excess of the Galactic value of 1.7 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.05 (+/-0.09) and a best-fitting absorption column of 1.34 (+0.26, -0.25) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.34 (+0.26, -0.25) x 10^21 cm^-2 Galactic foreground: 1.7 x 10^20 cm^-2 Excess significance: 7.8 sigma Photon index: 2.05 (+/-0.09) If the light curve continues to decay with a power-law decay index of -0.04, the count rate at T+24 hours will be 0.23 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.6 x 10^-12 (9.9 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00612804. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16826 SUBJECT: GRB 140916A: UKIRT J-band observations DATE: 14/09/16 23:19:37 GMT FROM: Wen-fai Fong at U of Arizona W. Fong, P. Milne, N. Smith and J. Andrews (U. Arizona) report on behalf of the Arizona Transient Exploration and Characterization (AZTEC) collaboration: "We observed the field of the Swift-detected GRB 140916A (Racusin et al., GCN 16819) with UFTI mounted on the 3.8-m United Kingdom Infrared Telescope (UKIRT) on Mauna Kea beginning on 2014 Sep 16.561 UT (2.7 hr post-burst). In 36-min of J-band imaging, we do not detect any near-IR source in or around the enhanced XRT position (Evans et al., GCN 16820; Osborne et al., GCN 16824). Calibrated to 2MASS, we therefore place a 3-sigma limit of J(VEGA)>21 mag on the near-IR afterglow of GRB 140916A at 2.7 hr post-burst. We thank T. Carroll for assistance with these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16827 SUBJECT: GRB 140916A: Swift-BAT refined analysis DATE: 14/09/17 00:23:32 GMT FROM: Takanori Sakamoto at AGU M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC), T. Sakamoto (AGU), J. Tueller (GSFC), 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 140916A (trigger #612804) (Racusin, et al., GCN Circ. 16819). The BAT ground-calculated position is RA, Dec = 40.384, -39.688 deg which is RA(J2000) = 02h 41m 32.2s Dec(J2000) = -39d 41' 18.6" with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 16%. The mask-weighted light curve shows a single peak starting at T-3 sec, peaking at T+3 sec and ending at T+100 sec. T90 (15-350 keV) is 80.1 +- 15.6 sec (estimated error including systematics). The time-averaged spectrum from T-6.6 to T+89.5 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.15 +- 0.27. The fluence in the 15-150 keV band is 1.7 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+1.80 sec in the 15-150 keV band is 1.3 +- 0.4 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/612804/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16828 SUBJECT: GRB 140916A: Swift/UVOT Upper Limits DATE: 14/09/17 00:26:30 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140916A 160 s after the BAT trigger (Racusin et al., GCN Circ. 16819). No optical afterglow consistent with the XRT position (Evans GCN Circ. 16820) 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 160 310 147 >21.5 u_FC 318 568 246 >20.7 white 160 6731 608 >22.3 v 648 12894 1415 >21.2 b 574 19208 857 >20.8 u 318 24969 2113 >21.4 w1 697 30730 2826 >21.9 m2 844 30169 2742 >21.7 w2 796 29263 2203 >22.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).