//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18818 SUBJECT: GRB 160104B: MAXI/GSC detection DATE: 16/01/04 12:54:30 GMT FROM: H. Negoro at Nihon U. Y. Kawakubo (AGU), M. Nakajima, H. Negoro (Nihon U.), M. Serino (RIKEN), S. Ueno, H. Tomida, S. Nakahira, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, 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, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), 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, D. Itoh, 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 10:13:03 UT on on 2016 January 4. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (108.879 deg, 54.865 deg) = (07 15 30, +54 51 54) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.32 deg and 0.29 deg, respectively. The roll angle of long axis from the north direction is 72.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 123 +- 24 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) = (109.823 deg, 54.028 deg) = (07 19 17, +54 01 40) (J2000) (R.A., Dec) = (108.777 deg, 53.855 deg) = (07 15 06, +53 51 17) (J2000) (R.A., Dec) = (107.662 deg, 55.997 deg) = (07 10 38, +55 59 47) (J2000) (R.A., Dec) = (108.739 deg, 56.218 deg) = (07 14 57, +56 13 04) (J2000) There was no significant excess flux in the previous transit at UT 08:40 UT on 2016 January 4 with an upper limit of 20 mCrab for each. For more information: http://maxi.riken.jp/alert/novae/7391314067/7391314067.htm //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18869 SUBJECT: Konus-Wind observation of GRB 160104B DATE: 16/01/15 09:48:49 GMT FROM: Anna Kozlova at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline, on behalf of the Konus-Wind team, report: GRB 160104B, localized by MAXI/GSC (Kawakubo et al., GCN 18818) was detected by Konus-Wind in the waiting mode. The K-W light curve shows two distinct emission episodes. The first one, from ~T0(MAXI)-25.9 s to ~T0(MAXI)+6.5 s, corresponds to the MAXI trigger(T0(MAXI)=10:13:06.662 UT). The second episode is separated from the first one by ~500 s and lasts for ~165 s, from ~T0(MAXI)+515.8 s to ~T0(MAXI)+680.7 s. The K-W ecliptic latitude response in both episodes is consistent with the position of GRB 160104B. Taking this into account, we suggest that both episodes observed by K-W belong to GRB 160104B and the total duration of the burst is ~710 s. The K-W light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB160104B/ As observed by Konus-Wind, the first episode had a fluence of 6.64(-0.81,+0.87)x10^-6 erg/cm2 and a 2.944-s peak flux, measured from ~T0(MAXI)-22.915 s, of 5.23(-0.88,+0.92)x10^-7 erg/cm2/s (both in the 20 - 1200 keV energy range). The second episode had a fluence of 1.36(-0.17,+0.17)x10^-5 erg/cm2 and a 2.944-s peak flux, measured from ~T0(MAXI)+615.933 s, of 3.59(-0.75,+0.75)x10^-7 erg/cm2/s (both estimated in the same energy range). Fitting the K-W 3-channel time-integrated spectrum of the first episode (from ~T0(MAXI)-25.9 s to ~T0(MAXI)+6.5 s) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -0.8(-0.2,+0.3) and Ep = 489 (-114,+195) keV. Fitting the K-W 3-channel time-integrated spectrum of the second episode (from ~T0(MAXI)+515.8 s to ~T0(MAXI)+680.7 s) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.4(-0.2,+0.2) and Ep = 481 (-175,+580) keV. All the quoted errors are estimated at the 1 sigma confidence level. All the presented results are preliminary.