TITLE: GCN CIRCULAR NUMBER: 31756 SUBJECT: IPN triangulation of GRB 220310A DATE: 22/03/14 21:25:39 GMT FROM: Anna Ridnaia at Ioffe Institute A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars-Odyssey team, A. Ridnaia, D. Frederiks, D. Svinkin, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 220310A (MAXI/GSC detection: Negoro et al., GCN Circ. 31725; CALET-CGBM detection: Yoshida et al., GCN Circ. 31730; Konus-Wind detection: Svinkin et al., GCN Circ. 31748) was detected by MAXI(GSC), CALET (GBM), Konus-Wind, and Mars-Odyssey (HEND) at about 1702 s UT (00:28:22). We have triangulated it to a Konus-HEND annulus centered at RA(2000)=124.878 deg (08h 19m 31s) Dec(2000)=+20.557 deg (+20d 33' 25"), whose radius is 40.183 +/- 0.041 deg (3 sigma). The MAXI/GSC localization is consistent with the annulus. The position of the optical transient J111302.33+231508.0 (Lipunov et al., GCN Circ. 31732) is inside the annulus at 0.7 arcmin from its center line. The positional and temporal coincidence of this burst with the OT supports the conclusion that the OT is the GRB counterpart. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB220310_T01702/IPN