//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18793 SUBJECT: GRB 160101A: MAXI/GSC detection DATE: 16/01/01 02:40:46 GMT FROM: H. Negoro at Nihon U. D. Itoh (Miyazaki U.), H. Negoro (Nihon U.), H. Tomida, S. Nakahira, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, M. Arimoto, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R.Imatani (Osaka U.), M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori, A. Tanimoto (Kyoto U.), Y. Tsuboi, S. Kanetou, Y. Nakamura, R. Sasaki (Chuo U.), M. Yamauchi, K. Furuya (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Morii (ISM) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 00:43:52 UT on 2016 January 1. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (219.733 deg, -13.823 deg) = (14 38 55, -13 49 22) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.10 deg and 0.09 deg, respectively. The roll angle of long axis from the north direction is 150.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 1543 +- 100 mCrab (4-10keV, 1 sigma error). Without assumptions on the source constancy,we obtain a rectangular error box for the transient source with the following corners: (R.A., Dec) = (219.635 deg, -14.100 deg) = (14 38 32, -14 05 59) (J2000) (R.A., Dec) = (219.486 deg, -13.957 deg) = (14 37 56, -13 57 24) (J2000) (R.A., Dec) = (220.532 deg, -12.732 deg) = (14 42 07, -12 43 54) (J2000) (R.A., Dec) = (220.677 deg, -12.878 deg) = (14 42 42, -12 52 39) (J2000) There was no significant excess flux in the previous transit at 23:11 UT on 2015 December 31 with an upper limit of 20 mCrab for each. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18794 SUBJECT: GRB 160101A: Tiled Swift observations DATE: 16/01/01 04:32:17 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 MAXI GRB 160101A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00051 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 MAXI 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: 18795 SUBJECT: GRB 160101A: Swift-XRT afterglow detection DATE: 16/01/01 15:30:06 GMT FROM: Valerio D'Elia at ASDC L. Izzo (URoma/ICRA), V. D'Elia (ASDC), P. D'Avanzo (INAF-OAB), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), S.L. Gibson (U. Leicester), A. D'Ai (INAF-IASFPA) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 160101A (Itoh et al. GCN Circ. 18793) in a series of observations tiled on the sky. The total exposure time is 1.7 ks, distributed over 7 tiles; the maximum exposure at a single sky location was 512 s. The data were collected between T0+13.2 ks and T0+19.6 ks, and are entirely in Photon Counting (PC) mode. An uncatalogued X-ray source is detected and is above the RASS limit, and is therefore likely the GRB afterglow. The position of this source is RA, Dec=219.6506, -13.8154 which is equivalent to: RA (J2000): 14:38:36.14 Dec(J2000): -13:48:55.5 with an uncertainty of 3.7 arcsec (radius, 90% confidence). This position is 4.8 arcmin from the MAXI position. The source has a mean count rate of 3.9e-01 ct/sec; we cannot determine at the present time whether it is fading. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.5 (+0.5, -0.3). The best-fitting absorption column is 1.20 (+2.17, -0.29) x 10^21 cm^-2, consistent with the Galactic value of 9.1 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 4.6 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.20 (+2.17, -0.29) x 10^21 cm^-2 Galactic foreground: 9.1 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.5 (+0.5, -0.3) The results of the XRT-team automatic analysis of the likely afterglow are at http://www.swift.ac.uk/xrt_products/TILED_GRB00051/index_1.php. The results of the full analysis of the tiled XRT observations are available at http://www.swift.ac.uk/xrt_products/TILED_GRB00051. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18796 SUBJECT: GRB 160101A: Fermi GBM observation DATE: 16/01/01 15:45:16 GMT FROM: Peter Veres at UAH P Veres (UAH) reports on behalf of the Fermi GBM Team: "At 00:43:53.61 UT on 01 January 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160101A (trigger 473301837 / 160101030) which was also detected by MAXI/GSC (Itoh et al., GCN 18793) and Swift/XRT (Izzo et al., GCN 18795). The GBM on-ground location is consistent with the MAXI and Swift positions. The angle from the Fermi LAT boresight at the GBM trigger time is 93 degrees. The GBM light curve consists of a single pulse with a duration (T90) of about 4.7 s (50-300 keV). The time-averaged spectrum from T0 to T0+7.3 s is best fit by a Band function with Epeak = 135.0 +/- 5.2 keV, alpha = -0.78 +/- 0.03, and beta = -2.26 +/- 0.05. The event fluence (10-1000 keV) in this time interval is (1.682 +/- 0.024)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.9 s in the 10-1000 keV band is 35.7 +/- 0.9 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: 18797 SUBJECT: GRB 160101A: Swift/UVOT Detection DATE: 16/01/01 15:52:34 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and V. D'Elia (ASDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began tiled observations of the field of the MAXI-detected burst GRB 160101A (Itoh et al. GCN Circ. 18793) 13.2 ks after the burst. A fading optical source consistent with position of the XRT source reported by Izzo et al. (GCN Circ. 18795) is detected in the initial UVOT exposures in the u filter. The preliminary UVOT position is: RA (J2000) = 14:38:36.12 = 219.65051 (deg.) Dec (J2000) = -13:48:55.4 = -13.81539 (deg.) with an estimated uncertainty of 0.58 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag u 13195 13397 198 17.55+-0.10 u 19592 19652 59 18.32+-0.32 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.09 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18805 SUBJECT: GRB 160101A: MITSuME Akeno optical upper limits DATE: 16/01/02 17:14:36 GMT FROM: Taketoshi Yoshii at Tokyo Tech T.Fujiwara, Y.Saito,T.Yoshii, Y.Tachibana, Y.Yano, Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 160101A (D.Itoh et al., GCN Circular #18793) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2016-01-01 18:33:56 UT (~17.8 h after the burst). We cound not detect any optical point source in the error circle of the previously reported afterglow detected by Swift-XRT (L.Izzo et al., GCN Circular #18795) in all three bands. Three sigma upper limits are listed below. T0+[hour] MID-UT T-EXP[sec] g' Rc Ic --------------------------------------------------------------------------------------- 18.9839 20:18:08 780 > 18.5 > 18.2 > 17.4 --------------------------------------------------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18814 SUBJECT: GRB 160101A: CALET Gamma-Ray Burst Monitor detection DATE: 16/01/04 07:54:40 GMT FROM: Takanori Sakamoto at AGU Y. Yamada, A. Yoshida, T. Sakamoto, I. Takahashi, Y. Kawakubo, K. Senuma, M. Moriyama (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena) and the CALET collaboration: The long-duration GRB 160101A (Itoh et al. GCN Circ. 18793; Veres et al. GCN Circ. 18796) triggered the CALET Gamma-Ray Burst Monitor (CGBM) at 00:43:54.04 UT on 1 January 2016. The clear burst signal was detected by all instruments. The light curve of the HXM shows a multiple peak structure starting at T0-2 sec and ending at T0+8 sec. The T90 duration measured by the HXM1 data is 7.2 +- 1.3 sec (7-100 keV). The CGBM data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18838 SUBJECT: Konus-Wind observation of GRB 160101A DATE: 16/01/07 19:54:28 GMT FROM: Dmitry Svinkin at Ioffe Institute 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, intense GRB 160101A (MAXI detection: Itoh et al., GCN Circ. 18793; Fermi GBM detection: Veres, GCN Circ. 18796) triggered Konus-Wind at T0=2631.931 s UT (00:43:51.931). The burst light curve shows a single pulse with a total duration of ~4.6 s. The emission is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB160101_T02631/ As observed by Konus-Wind, the burst had a fluence of 1.47(-0.17,+0.21)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+0.214 s, of 1.18(-0.30,+0.35)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 the GRB (Band) model with the following parameters: the low-energy photon index alpha = -1.19(-0.19,+0.25), the high energy photon index beta = -2.86(-7.14,+0.38), the peak energy 143(-19,+20) keV (chi2 = 103/83 dof). The spectrum near the maximum count rate (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.06(-0.23,+0.27) and Ep = 612(-175,+321) keV (chi2 = 26/41 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta <-2.0 (chi2 = 26/40 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.