//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20722 SUBJECT: IPN Triangulation of GRB 170222A (short/hard) DATE: 17/02/22 13:52:53 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, S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT 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 170222A has been detected by Fermi (GBM trigger 509432464), Konus-Wind, INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), Swift (BAT), and CALET (GBM), so far, at about 18059 s UT (05:00:59). The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 292.956 (19h 31m 49s) +28.211 (+28d 12' 40") Corners: 292.896 (19h 31m 35s) +27.812 (+27d 48' 44") 292.864 (19h 31m 27s) +28.266 (+28d 15' 59") 293.017 (19h 32m 04s) +28.608 (+28d 36' 28") 293.048 (19h 32m 12s) +28.156 (+28d 09' 22") --------------------------------------------- The error box area is 254 sq. arcmin, and its maximum dimension is 0.8 deg (the minimum one is 9.36 arcmin). The Sun distance was 56 deg. This box may be improved. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB170222_T18056/IPN/ A Swift ToO request has been approved. The time history and spectrum will be given in forthcoming GCN Circulars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20725 SUBJECT: GRB 170222A: Swift ToO observations DATE: 17/02/22 14:32:19 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the IPN GRB 170222A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020741 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the IPN event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20726 SUBJECT: GRB 170222A: Tiled Swift observations DATE: 17/02/22 15:27:14 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the IPN GRB 170222A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00064 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the IPN event is high: any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20728 SUBJECT: GRB 170222A: Fermi GBM observation DATE: 17/02/22 22:52:42 GMT FROM: Rachel Hamburg at UAH R. Hamburg (UAH), E. Bissaldi (Politecnico & INFN Bari), and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 05:00:59.08 UT on 22 February 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170222A (trigger 509432464 / 170222209), which was also reported by IPN (Hurley et al. 2017, GCN 20722). The on-ground calculated location, using the GBM trigger data, is RA = 312.10, DEC = +12.45 (J2000 degrees, equivalent to 20h 48m, 12d 27'), with an uncertainty of 3.6 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] ). Although the GBM localization is not consistent within 3 sigma of the IPN localization, the GBM localization places this event in the same part of the sky and is the same event as that reported by IPN. The angle from the Fermi LAT boresight at the GBM trigger time using the IPN position is 120 degrees. The GBM light curve shows a single multi-peaked emission episode with a duration (T90) of about 1.7 s (50-300 keV). The time-averaged spectrum from T0-0.64 s to T0+2.43 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.70 +/- 0.08 and the cutoff energy, parameterized as Epeak, is 862 +/- 118 keV. The event fluence (10-1000 keV) in this time interval is (5.31 +/- 0.19)E-06 erg/cm^2. The 0.64-sec peak photon flux measured starting from T0+1.15 s in the 10-1000 keV band is 17.4 +/- 1.9 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: 20729 SUBJECT: GRB 170222A: Swift-XRT observations DATE: 17/02/23 16:51:35 GMT FROM: Antonino D'Ai at IASF-PA A. D'Ai (IASF-PA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the IPN-detected burst GRB 170222A in a series of observations tiled on the sky and covering the entire IPN error box. The total exposure time is 5.3 ks, distributed over 3 tiles; the maximum exposure at a single sky location was 3.2 ks. The data were collected between T0+33.8 ks and T0+38.9 ks, and are entirely in Photon Counting (PC) mode. Three uncatalogued X-ray sources are detected: Source 1: RA (J2000.0): 292.95293 = 19h 31m 48.70s Dec (J2000.0): 28.04614 = +28:02:46.1 Error: 5.0 arcsec Count-rate: 1.01 (+0.21, -0.20) × 10-2 ct/s Source 2: RA (J2000.0): 292.68930 = 19h 30m 45.43s Dec (J2000.0): 27.96842 = +27:58:06.3 Error: 5.7 arcsec Count-rate: 2.4 (+0.9, -0.7) × 10-2 ct/s Source 3: RA (J2000.0): 293.02439 = 19h 32m 05.85s Dec (J2000.0): 28.26746 = +28:16:02.9 Error: 3.1 arcsec Count-rate: 8.0 (+2.8, -2.3) ×10-3 ct/s However, none of these is a credible afterglow candidate. Source 2 is outside the IPN errorbox, while sources 1 and 3 match Simbad sources NVSS J193148+280248 and CCDM J19321+2816BC. Sources 2 and 3 are affected by optical loading and might be spurious detections. The Swift XRT observations did not cover the Fermi GBM error circle reported by Hamburg et al. (GCN #20728). The results of the full analysis of the tiled XRT observations are available at http://www.swift.ac.uk/xrt_products/TILED_GRB00064. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20731 SUBJECT: Konus-Wind observation of GRB 170222A DATE: 17/02/24 12:52:25 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 short-duration GRB 170222A (IPN triangulation: Hurley et al., GCN 20722; Fermi GBM observation: Hamburg et al., GCN 20728) triggered Konus-Wind at T0=18056.528 s UT (05:00:56.528). The burst light curve shows a multi-peaked structure which starts at ~T0-0.1 s and has a total duration of ~1.9 s. The emission is seen up to ~10 MeV. As observed by Konus-Wind, the burst had a fluence of 9.10(-2.43,+3.61)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+1.104 s, of 1.23(-0.46,+0.76)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+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 = -0.72(-0.26,+0.36) and Ep = 1210(-418,+830) keV (chi2 = 73/88 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.28 (chi2 = 73/87 dof) The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB170222_T18056/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20749 SUBJECT: GRB 170222A: CALET Gamma-Ray Burst Monitor detection DATE: 17/02/26 10:06:52 GMT FROM: Takanori Sakamoto at AGU S. Ricciarini (U of Florence), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), P. S. Marrocchesi (U of Siena) and the CALET collaboration: The short-duration GRB 170222A (Hamburg et al., GCN Circ. 20728; Kozlova et al., GCN Circ. 20731; INTEGRAL-SPI/ACS trigger #7705) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 05:00:58.48 on 22 February 2017. The burst signal was only seen by the SGM instruments. The light curve of the SGM shows several peaks. The entire burst episode starts at T0+0.5 sec, peaks at T0+0.8 sec and ends at T0+2 sec. The T90 duration measured by the SGM data is 1.2 +- 0.1 sec (40-1000 keV). The light curve is available at http://cgbm.calet.jp/cgbm_trigger/flight/1171774567/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.