{
  "subject": "GRB 231205A: joint location of multiple instruments by ETJASMIN ",
  "submittedHow": "web",
  "body": "Yanting Zhang, Shaolin Xiong, Yue Huang, Shuo Xiao, Xiaoyun Zhao, Ping Wang, \nreport on behalf of the GECAM team:\n\nThe short burst, GRB 231205A, has been detected by GECAM-B (Tan et al., GCN 35266), Fermi/GBM (Fermi/GBM team, GCN 35263) and INTEGRAL/SPI-ACS. With the ETJASMIN pipeline (Energetic Transients joint analysis system for Multi-INstrument, Xiao et al., MNRAS, 514, 2397, 2022) and the realtime data of GECAM-B, INTEGRAL/SPI-ACS and Fermi/GBM, we did a low-latency joint location for this burst.\n\nFirstly, we applied the Li-CCF method (Xiao et al., ApJ, 920, 43, 2021) to the realtime high temporal resolution (~1 ms) light curve of GECAM-B and the low-latency public 50 ms light curve of INTEGRAL/SPI-ACS, and derived the triangulation location as the following annuli:\n\n--------------------------------------------------------------------------------------------------\nAnnulus                 Ra (deg)      Dec (deg)     Radius (deg)      Radius-Error (deg, 3sigma)\nGECAM-B + SPI-ACS       209.519       59.889        40.961            1.272\n--------------------------------------------------------------------------------------------------\n\nThen, we combined this annulus location, the stand-alone locations provided by GECAM-B (Tan et al., GCN 35266) and Fermi/GBM (Fermi/GBM team, GCN 35263), as well as the Earth occultation of these instruments, and derived a refined location, which is much smaller than stand-alone ones. \n\nThis refined location (~3 sigma region) could be approximately described by a polygon region,\nwhose center and corners are:\n\n--------------------------------------\n            Ra (deg)      Dec (deg)\nCenter      205.313\t  19.155   \nCorner1     215.859       19.155\nCorner2     209.883       18.724\nCorner3     202.148       18.871\nCorner4     194.766       20.427\nCorner5     205.313       19.524\n--------------------------------------\n\nFor this refined location, the sky map and probability data could be found at:\nSky map: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/GRB231205A-jointLoc-skymap-v01.png\nData file: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/GRB231205A-jointLoc-healpix-v01.fits\n\n\nETJASMIN is developed for joint observation of high energy transients by the GECAM team.\nWe acknowledge the public data of Fermi/GBM and INTEGRAL/SPI-ACS. ",
  "submitter": "yqzhang_cl@163.com",
  "bibcode": "2023GCN.35268....1Z",
  "circularId": 35268,
  "createdOn": 1701794010620,
  "eventId": "GRB 231205A"
}