TITLE: GCN CIRCULAR NUMBER: 22588 SUBJECT: Konus-Wind observation of GRB 180402A DATE: 18/04/03 16:59:32 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report: The short-duration, hard-spectrum GRB 180402A (Swift-BAT detection: Lien et al., GCN Circ. 22580; Fermi-GBM detection: Malacaria, GCN Circ. 22585) triggered Konus-Wind at T0=35100.353 s UT (09:45:00.353). The burst light curve shows bright, multi-peaked emission episode, which starts at T0-64 ms and has a total duration of ~180 ms, preceded by a weaker pulse at ~T0-340 ms. As observed by Konus-Wind, the burst had a fluence of 2.14(-0.33,+0.53)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.086 s, of 2.03(-0.45,+0.60)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). Since the most intense part of the burst was detected before the trigger, the spectral analysis was performed using the KW 3-channel light curve data. Modeling the KW 3-channel spectrum of the main episode (from T0-0.064 s to T0+0.116 s) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -0.01(-0.43,+0.64), and Ep = 703(-161,+276) keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180402_T35100 All the quoted errors are at the 68% confidence level. All the quoted values are preliminary.