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.