//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20556 SUBJECT: GRB 170124A: CALET Gamma-Ray Burst Monitor detection DATE: 17/01/28 04:30:56 GMT FROM: Takanori Sakamoto at AGU W. Ishizaki (ICRR), 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), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena) and the CALET collaboration: The long-duration GRB 170124A (Fermi-GBM trigger #506984291; Konus-Wind trigger time on 20:58:06.428 UT) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 20:58:04.58 on 24 January 2017. The burst signal was seen by all CGBM instruments. The light curve of the SGM shows two peaks. The first peak starts at T0, peaks at T+8 sec and ends at T+15 sec. The second peak starts at T+15 sec, peaks at T+23 sec and ends at T+30 sec. The T90 duration measured by the SGM data is 20.9 +- 1.3 sec (40-1000 keV). The light curve is available at http://cgbm.calet.jp/cgbm_trigger/flight//1169326441/index.html The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20559 SUBJECT: GRB 170124A: POLAR Observation DATE: 17/01/28 12:40:29 GMT FROM: Zhao Yi at POLAR Yi Zhao (IHEP), R. Marcinkowski (PSI), Xing Wen (IHEP), H. Xiao (PSI), Minzi Feng (IHEP) and W. Hajdas (PSI) report on behalf of the POLAR collaboration: At 2017-01-24T20:58:06.00 UT (T0), during a routine on-ground search of data, POLAR detected the GRB 170124A, which was also detected by the Fermi/GBM (trigger 506984291/170124873), Konus-Wind and the CALET Gamma-ray BurstMonitor (Circ 20556). The POLAR light curve consists of multiple peaks, with a duration (T90) of 22.38 s measured from T0+2.26 s. The 1-s peak rate measured from T0+8.00 s is 514.8 cnts/s. The total counts is about 7657 cnts. The above measurements are in the energy range of about 80-500 keV. LC_URL: http://polar.ihep.ac.cn/grb/2017/01/GRB170124A/lc/POLAR_lc_grb170124A.png Using the best location from the Fermi/GBM, which is (J2000): RA: 282.040 [deg] Dec: -75.510 [deg] Err: 1.00 [deg] the incident angle in POLAR coordinate at T0 is: theta: 111.4 [deg] phi: -143.2 [deg] All analysis results presented above are preliminary. POLAR is a dedicated Gamma-Ray Burst polarimeter (50-500 keV) on-board the Chinese space laboratory Tiangong-2 launched on Sep 15,2016. More information about POLAR can be found at http://polar.ihep.ac.cn/en/ , http://isdc.unige.ch/polar/ and http://polar.psi.ch/pub/.