//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19014 SUBJECT: GRB 160216A: Swift detection of a burst DATE: 16/02/16 19:23:21 GMT FROM: Scott Barthelmy at NASA/GSFC E. Troja (NASA/GSFC/UMCP), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), S. B. Cenko (GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), L. M. McCauley (PSU), T. G. R. Roegiers (PSU), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 19:10:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160216A (trigger=673978). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 311.706, -71.555 which is RA(J2000) = 20h 46m 49s Dec(J2000) = -71d 33' 17" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several bright peaks with a duration of about 30 sec. The peak count rate was ~7000 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 19:12:05.3 UT, 93.9 seconds after the BAT trigger. The position determined from promptly downlinked data differs significantly from the on-board position, suggesting that the XRT may have centroided on a cosmic ray; the initial XRT position notice should be treated with caution. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 311.68630, -71.54787 which is equivalent to: RA(J2000) = 20h 46m 44.71s Dec(J2000) = -71d 32' 52.3" with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 34 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 (4.50 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 1.1 (+0.67/-0.50) x 10^22 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 100 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 0.05. Burst Advocate for this burst is E. Troja (eleonora.troja 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: 19015 SUBJECT: GRB 160216A: Enhanced Swift-XRT position DATE: 16/02/16 23:22:45 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 400 s of XRT Photon Counting mode data and 1 UVOT images for GRB 160216A, 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 = 311.68414, -71.54837 which is equivalent to: RA (J2000): 20h 46m 44.19s Dec (J2000): -71d 32' 54.1" 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: 19016 SUBJECT: GRB 160216A: Swift/UVOT Upper Limits DATE: 16/02/17 00:04:06 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160216A 101 s after the BAT trigger (Troja et al., GCN Circ. 19014). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 19015) has been 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 101 251 147 >19.8 u_FC 314 564 246 >19.1 white 101 5921 541 >20.6 v 4695 6301 364 >19.0 b 4079 5716 393 >19.9 u 314 5510 442 >19.3 w1 5105 5305 197 >19.4 m2 4900 5099 197 >19.7 w2 4490 6126 393 >20.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19018 SUBJECT: GRB 160216A: Swift-XRT refined Analysis DATE: 16/02/17 08:31:13 GMT FROM: Phil Evans at U of Leicester A. D'Ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester) and E. Troja report on behalf of the Swift-XRT team: We have analysed 7.5 ks of XRT data for GRB 160216A (Troja et al. GCN Circ. 19014), from 81 s to 34.6 ks after the BAT trigger. The data comprise 36 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 Beardmore et al. (GCN Circ. 19015). The light curve can be modelled with a power-law decay with a decay index of alpha=0.996 (+0.026, -0.025). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.90 (+0.18, -0.17). The best-fitting absorption column is 5.4 (+1.2, -1.0) x 10^21 cm^-2, in excess of the Galactic value of 4.5 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 4.4 x 10^-11 (6.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 5.4 (+1.2, -1.0) x 10^21 cm^-2 Galactic foreground: 4.5 x 10^20 cm^-2 Excess significance: 7.8 sigma Photon index: 1.90 (+0.18, -0.17) If the light curve continues to decay with a power-law decay index of 0.996, the count rate at T+24 hours will be 0.010 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.4 x 10^-13 (6.9 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/00673978. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19019 SUBJECT: Konus-Wind observation of GRB 160216A (and GRB 160216B) DATE: 16/02/17 13:51:14 GMT FROM: Anna Kozlova at Ioffe Institute A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 160216A (Swift-BAT trigger #673978: Troja et al., GCN Circ. 19014) triggered Konus-Wind at T0=69030.129 s UT (19:10:30.129). The burst light curve shows a double-peaked structure started at ~T0-0.3 s with a total duration (80-1400 keV) of ~3.6 s. The emission is seen up to ~4 MeV. As observed by Konus-Wind, the burst had a fluence of 3.05(-0.35,+0.39)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+2.864 s, of 2.62(-0.70,+0.71)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.66 (-0.31,+0.36) and Ep = 140 (-18,+25) keV (chi2 = 91/87 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.0 (chi2 = 91/86 dof) The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB160216_T69030/ Another long-duration GRB 160216B was detected by Konus-Wind in the same trigger record at ~T0+150 s. This second burst was also detected by Fermi-GBM, trigger #477342778.The KW ecliptic latitude response for GRB 160216B is consistent with the GBM localization and inconsistent with the BAT localization of GRB 160216A. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19020 SUBJECT: GRB 160216A: Swift-BAT refined analysis DATE: 16/02/17 14:12:17 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), 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), T. Sakamoto (AGU), M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP), 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 downlinks, we report further analysis of BAT GRB 160216A (trigger #673978) (Troja, et al., GCN Circ. 19014). The BAT ground-calculated position is RA, Dec = 311.679, -71.550 deg, which is RA(J2000) = 20h 46m 43.0s Dec(J2000) = -71d 33' 01.0" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 48%. The mask-weighted light curve shows a small peak starting at ~T-0.3 sec, then two large peaks at ~T+0.6 s and ~T+3.2 sec, and ending at ~T+20 sec. T90 (15-350 keV) is 11.0 +- 1.0 sec (estimated error including systematics). The time-averaged spectrum from T-0.30 to T+11.70 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.48 +- 0.08. The fluence in the 15-150 keV band is 2.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.70 sec in the 15-150 keV band is 7.3 +- 0.5 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/673978/BA/