//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20616 SUBJECT: GRB 170206A: Fermi GBM observation DATE: 17/02/06 18:04:50 GMT FROM: Oliver J Roberts at USRA/NASA A. von Kienlin (MPE) and O.J. Roberts (USRA/NASA-MSFC) report on behalf of the Fermi GBM Team: "At 10:51:57.70 UT on February 6th 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170206A (trigger 508071122 /170206453). The on-ground calculated location, using the GBM trigger data, is RA = 211.80, DEC = +13.06, (J2000 degrees, equivalent to J2000 14h 07m, +/- 13d 03') with an uncertainty of 1.14 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg. error and a small tail suffering a larger than 10 deg. systematic error. [Connaughton et al. 2015, ApJS, 216, 32]). The trigger resulted in an Autonomous Repoint Request (ARR) by the GBM Flight Software owing to the high peak flux of the GRB. This ARR was accepted and the spacecraft slewed to the GBM in-flight location. The initial angle from the Fermi-LAT boresight to the GBM ground location is 67 degrees. The GBM light curve shows a short, bright burst with a duration (T90) of about 1.2 s (50-300 keV). The time-averaged spectrum from T0+0.1s to T0+1.3 s is best fit by a BAND function, with alpha= -0.28 +/- 0.04, beta= -2.55 +/- 0.12 and Epeak, is 341 +/- 13 keV. The event fluence (10-1000 keV) in this time interval is (1.34 +/- 0.02) E-05 erg/cm^2. The 64 ms peak photon flux measured starting from T0+0.6 s in the 10-1000 keV band is 57.0 +/- 2.1 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: 20617 SUBJECT: GRB 170206A: Fermi-LAT detection DATE: 17/02/06 20:02:31 GMT FROM: Donggeun Tak at UMCP/GSFC GRB 170206A: Fermi-LAT detection F. Fana Dirirsa (U. Johannesburg ), D.Tak (UMD/NASA-GSFC), G. Vianello (Stanford Univ.), J. Racusin (NASA/GSFC), D. Kocevski (NASA/MSFC) report on behalf of the Fermi-LAT team: At 10:51:57.70 on February, 06, 2017 Fermi-LAT detected high-energy emission from GRB 170206A which was also detected by Fermi-GBM starting at 10:51:57.70 UT (trigger 508071122 /170206453; Oliver J Roberts et al. GCN 20616). The best LAT on-ground location is found to be RA, Dec = 212.79, 14.48 (J2000) with an error radius of 0.85 deg (90 % containment, statistical error only). This was 67 deg from the LAT boresight at the time of the trigger. The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the trigger with high significance. The highest-energy photon is a 811 MeV event which is observed 5.17 seconds after the GBM trigger. The Fermi-LAT point of contact for this burst is Feraol Fana Dirirsa (fdirirsa@uj.ac.za ). 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: 20618 SUBJECT: GRB 170206B: Swift detection of a burst DATE: 17/02/06 22:29:11 GMT FROM: Scott Barthelmy at NASA/GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), A. Cholden-Brown (PSU), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), B. Mingo (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team: At 21:57:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170206B (trigger=737125). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 271.786, +11.223, which is RA(J2000) = 18h 07m 09s Dec(J2000) = +11d 13' 23" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Due to a processing outage, the real-time light curve is not available at this time. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 271.7708, 11.1943 which is equivalent to: RA(J2000) = 18h 07m 04.98s Dec(J2000) = +11d 11' 39.4" with an uncertainty of 2.2 arcseconds (radius, 90% containment). 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 (1.13 x 10^21 cm^-2, Willingale et al. 2013), with an excess column of 2.8 (+2.82/-2.42) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 250 seconds with the U filter. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. 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 18.0 mag. No correction has been made for the expected extinction of E(B-V) = 0.146. Burst Advocate for this burst is A. Y. Lien (amy.y.lien 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: 20619 SUBJECT: GRB 170206B: Enhanced Swift-XRT position DATE: 17/02/07 08:35:07 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Using 1338 s of XRT Photon Counting mode data and 1 UVOT image, 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 = 271.77061, 11.19366 which is equivalent to: RA (J2000): 18 07 04.95 Dec (J2000): +11 11 37.2 with an uncertainty of 1.9 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 is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20620 SUBJECT: GRB 170206B: Swift-XRT refined Analysis DATE: 17/02/07 09:46:41 GMT FROM: Phil Evans at U of Leicester S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and A.Y. Lien report on behalf of the Swift-XRT team: We have analysed 7.4 ks of XRT data for GRB 170206B (Lien et al. GCN Circ. 20618), from 88 s to 24.5 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. Using 2057 s of PC mode data and 3 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 271.77062, +11.19383 which is equivalent to: RA (J2000): 18h 07m 04.95s Dec(J2000): +11d 11' 37.8" with an uncertainty of 1.6 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=2.48 (+0.19, -0.20). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.46 (+0.18, -0.17). The best-fitting absorption column is 4.9 (+0.8, -0.7) x 10^21 cm^-2, in excess of the Galactic value of 1.1 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.1 x 10^-11 (6.9 x 10^-11) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 4.9 (+0.8, -0.7) x 10^21 cm^-2 Galactic foreground: 1.1 x 10^21 cm^-2 Excess significance: 8.5 sigma Photon index: 2.46 (+0.18, -0.17) If the light curve continues to decay with a power-law decay index of 2.48, the count rate at T+24 hours will be 2.5 x 10^-7 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.8 x 10^-18 (1.8 x 10^-17) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00737125. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20622 SUBJECT: GRB 170206B: Swift-BAT refined analysis DATE: 17/02/07 13:47:54 GMT FROM: Amy Lien at GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (NSF/USRA), 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+359 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170206B (trigger #737125) (Lien et al., GCN Circ. 20618). The BAT ground-calculated position is RA, Dec = 271.784, 11.175 deg which is RA(J2000) = 18h 07m 08.2s Dec(J2000) = +11d 10' 28.3" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 78%. The mask-weighted light curve shows a weak pulse that starts at ~T0 and ends at ~T+15 s. T90 (15-350 keV) is 13.36 +- 2.67 sec (estimated error including systematics). The time-averaged spectrum from T-0.33 to T+15.53 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.42 +- 0.27. The fluence in the 15-150 keV band is 3.2 +- 0.6 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.32 sec in the 15-150 keV band is 0.4 +- 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/737125/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20623 SUBJECT: IPN Triangulation of GRB 170206A (short/hard) DATE: 17/02/07 21:01:15 GMT FROM: Dmitry Svinkin at Ioffe Institute K. Hurley, on behalf of the IPN, I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report: The short-duration, hard-spectrum GRB 170206A (Fermi-GBM detection: von Kienlin and Roberts, GCN Circ. 20616; Fermi-LAT detection: Fana Dirirsa et al., GCN Circ. 20617) was detected by Fermi (GBM), Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND) at about 39118 s UT (10:51:58). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 212.633 (14h 10m 32s) +14.238 (+14d 14' 17") Corners: 212.341 (14h 09m 22s) +14.997 (+14d 59' 50") 212.901 (14h 11m 36s) +14.095 (+14d 05' 41") 212.915 (14h 11m 40s) +13.455 (+13d 27' 20") 212.365 (14h 09m 28s) +14.378 (+14d 22' 41") --------------------------------------------- The error box area is 1156 sq. arcmin, and its maximum dimension is 1.64 deg (the minimum one is 18.2 arcmin). The Sun distance was 110 deg. This box may be improved. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB170206_T39121/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20624 SUBJECT: GRB 170206A: POLAR observation DATE: 17/02/07 21:13:46 GMT FROM: Yuanhao Wang at IHEP/CAS Yuanhao Wang (IHEP), Shaolin Xiong (IHEP), Yi Zhao (IHEP) report on behalf of the POLAR collaboration: At 2017-02-06T10:51:57.70 UT (T0), during a routine on-ground search of data, POLAR detected the GRB 170206A, which was also detected by Fermi/GBM (trigger 508071122/170206453; A. von Kienlin et al. GCN 20616), Fermi/LAT(F. Fana Dirirsa et al. GCN 20617) and INTEGRAL/SPIACS(trigger_num 7680). The POLAR light curve consists of multiple peaks, with a duration (T90) of 1.194 s measured from T0+0.147 s. The 0.1s peak rate measured from T0+0.4s is 16145.2 cnts/s. The total counts is about 12918 cnts. LC_URL: http://polar.ihep.ac.cn/grb/2017/02/GRB170206A/lc/POLAR_lc_grb170206A.png The above result is not dead time corrected. The above measurements are in the energy range of about 20-500 keV. Using the best location from the Fermi/LAT, which is (J2000): RA: 212.79 [deg] Dec: +14.48 [deg] Err: 0.85  [deg] (90% containment, statistical error only) the incident angle in POLAR coordinate at T0 is: theta: 19.5 [deg] phi: 148.70 [deg] The Minimum Detectable Polarization(MDP) for this burst is estimated to be ~5.7% [1-sigma, statistical only]. Follow-up observations are strongly encouraged. All analysis results presented above are preliminary. POLAR is a dedicated Gamma-Ray Burst polarimeter (50-500 keV) on-board the Chinese space laboratory Tiangong-2 launched on Sep 15,2016. More information about POLAR can be found at http://polar.ihep.ac.cn/en/ , http://isdc.unige.ch/polar/ and http://polar.psi.ch/pub/ . //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20625 SUBJECT: Konus-Wind observation of GRB 170206A DATE: 17/02/07 21:17:17 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report: The short-duration, hard-spectrum, bright GRB 170206A (Fermi-GBM detection: von Kienlin and Roberts, GCN Circ. 20616; Fermi-LAT detection: Fana Dirirsa et al., GCN Circ. 20617; IPN triangulation: Hurley et al., GCN Circ. 20623) triggered Konus-Wind at T0=39121.226 s UT (10:52:01.226). The burst light curve shows a multipeaked structure started at ~T0-0.2 s with a total duration of ~1.5 s. The emission is seen up to ~15 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB170206_T39121/ As observed by Konus-Wind, the burst had a fluence of 1.49(-0.15,+0.16)x10^-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.306 s, of 3.30(-0.64,+0.66)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+1.280 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 = 0.00(-0.20,+0.24), the high energy photon index beta = -2.28(-0.18,+0.13), the peak energy Ep = 260(-29,+33) keV (chi2 = 58/61 dof) All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20626 SUBJECT: GRB 170206B: Swift/UVOT Upper Limits DATE: 17/02/07 21:35:31 GMT FROM: Sam Emery at MSSL-UCL S.W.K. Emery (UCL-MSSL) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 170206B 106 s after the BAT trigger (Lien et al., GCN Circ. 20618). No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 20619) 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 106 255 147 >20.3 u_FC 264 513 246 >19.6 white 106 1534 392 >20.7 v 594 1411 97 >18.2 b 519 1510 97 >19.1 u 226 1484 343 >19.7 w1 643 1460 97 >18.6 w2 569 1386 97 >19.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.146 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20639 SUBJECT: GRB 170206C: POLAR Observation DATE: 17/02/09 13:49:21 GMT FROM: Radek Marcinkowski at PSI/POLAR R. Marcinkowski (PSI), H. Xiao (PSI) and W. Hajdas (PSI) report on behalf of the POLAR collaboration: At 2017-02-06 11:40:10 UT(T0), during a routine on-ground search of data, POLAR detected GRB 170206C, which was also marginally observed by Integral/SPIACS (trigger 2017-02-06T11:40:10). The POLAR light curve consists of 2 peaks with duration (T90) of 16.0 +/- 0.5 s measured from T0. The 0.5 s peak flux at T0 + 3.2 s is equal to 1400 +/- 100 counts/sec. POLAR recorded about 9700 events from the burst. Above measurements are in the energy range of about 20 - 500 keV, presented light curve is not deadtime corrected. LC_URL: http://polar.psi.ch/triggers/GRB_170206C_raw.png or http://polar.psi.ch/pub/lc.php?event=GRB+170206C The analysis results presented above are preliminary. Calibration of the instrument is ongoing. POLAR is a dedicated Gamma-Ray Burst polarimeter which was launched on-board the Chinese space laboratory Tiangong-2 (TG-2) on Sep 15, 2016. The energy detection range of POLAR is ~ 50-500 keV. More information about POLAR can be found at http://polar.psi.ch/pub , http://polar.ihep.ac.cn/en/ and http://isdc.unige.ch/polar/ . This message is quotable in publications. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20787 SUBJECT: GRB 170206B: 15 GHz upper limits from AMI DATE: 17/03/01 16:43:13 GMT FROM: Kunal Mooley at Oxford U K. P. Mooley (Hintze Fellow, Oxford), T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester) The AMI Large Array observed the Swift GRB 170206B (Lien et al., GCN 20618) as part of the 4pisky program; follow up observations were obtained up to 10 days post-burst. Our observations at 15 GHz on 2016 Feb 08.37, Feb 09.38, Feb 14.43 and Feb 15.46 (UT) do not reveal any radio source at the XRT location (Evans et al., GCN 20619), with 3sigma upper limits of 123 uJy, 108 uJy, 108 uJy and 108 uJy respectively. We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.