TITLE: GCN CIRCULAR NUMBER: 35268 SUBJECT: GRB 231205A: joint location of multiple instruments by ETJASMIN DATE: 23/12/05 16:33:30 GMT FROM: yqzhang_cl@163.com Yanting Zhang, Shaolin Xiong, Yue Huang, Shuo Xiao, Xiaoyun Zhao, Ping Wang, report on behalf of the GECAM team: The 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. Firstly, 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: -------------------------------------------------------------------------------------------------- Annulus Ra (deg) Dec (deg) Radius (deg) Radius-Error (deg, 3sigma) GECAM-B + SPI-ACS 209.519 59.889 40.961 1.272 -------------------------------------------------------------------------------------------------- Then, 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. This refined location (~3 sigma region) could be approximately described by a polygon region, whose center and corners are: -------------------------------------- Ra (deg) Dec (deg) Center 205.313 19.155 Corner1 215.859 19.155 Corner2 209.883 18.724 Corner3 202.148 18.871 Corner4 194.766 20.427 Corner5 205.313 19.524 -------------------------------------- For this refined location, the sky map and probability data could be found at: Sky map: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/GRB231205A-jointLoc-skymap-v01.png Data file: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/GRB231205A-jointLoc-healpix-v01.fi... ETJASMIN is developed for joint observation of high energy transients by the GECAM team. We acknowledge the public data of Fermi/GBM and INTEGRAL/SPI-ACS. View this GCN Circular online at https://gcn.nasa.gov/circulars/35268. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...