{
  "bibcode": "2025GCN.39021....1S",
  "circularId": 39021,
  "eventId": "GRB 250121A",
  "subject": "GRB 250121A: CALET Gamma-Ray Burst Monitor detection",
  "createdOn": 1737729802698,
  "submittedHow": "web",
  "format": "text/plain",
  "body": "T. Sakamoto, A. Yoshida, S. Sugita, Y. Kawakubo (AGU),\nK. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii,\nY. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),\nN. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence),\nP. S. Marrocchesi (U of Siena),\nand the CALET collaboration:\n\nThe long GRB 250121A (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 39006;\nFermi-LAT detection: Holzmann Airasca et al., GCN Circ. 39010;\nINTEGRAL/SPI-ACS detection: Barria et al., GCN Circ. 39011;\nFermi GBM Observation: Godwin et al., GCN Circ. 39018;\n) was detected in the ground analysis of the CALET Gamma-ray \nBurst Monitor (CGBM) data around 23:36:05.78 on 21 January 2025 (referenced\nto the Fermi-GBM Observation: GCN Circ. 39018).\n(https://cgbm.calet.jp/cgbm_trigger/flight/1421537655/index.html).\nThe burst signal was seen by only the SGM detector. \n\nThe burst light curve shows a double-peaked structure that starts\nat T+0.1 sec, peaks at T+0.7 sec, and ends at T+5.4 sec.\nThe T90 and T50 durations measured by the SGM data are 4.7 +/- 0.2 sec\nand 2.6 +/- 0.4 sec (40-1000 keV), respectively.\n\nThe ground-processed light curve is available at\n\nhttps://cgbm.calet.jp/cgbm_trigger/ground/1421537655/\n\nThe CALET data used in this analysis are provided by\nthe Waseda CALET Operation Center located at Waseda University.",
  "submitter": "Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>"
}