TITLE: GCN CIRCULAR NUMBER: 20406 SUBJECT: LIGO/Virgo G268556: IPN Triangulation of GRB 170105A (association with ATLAS17aeu) DATE: 17/01/09 16:38:27 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Tsvetkova, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, and A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report: The long-duration, soft-spectrum GRB 170105A was detected by POLAR (Marcinkowski et al., GCN Circ. 20387), AstroSat (CZTI; Sharma et al., GCN Circ. 20389), Konus-Wind, and INTEGRAL (SPI-ACS) at about 22447 s UT (06:14:07). We have triangulated this GRB to a Konus-INTEGRAL annulus centered at RA(2000)=129.749 deg (08h 38m 60s) Dec(2000)=+27.904 deg (+27d 54' 14"), whose radius is 34.255(-14.832,+1.812) deg (3 sigma). This localization may be improved. The distance between the annulus center line and the ATLAS17aeu optical transient reported by Tonry et al. (LVC Circ. 20382) is 0.57 degrees, strengthening the association of the transient with the GRB initially suggested by Kasliwal et al. (LVC Circ. 20393). A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB170105_T22450/IPN/. As observed by Konus-Wind, the burst had a fluence of 2.56(-0.13,+0.18)x10^-6 erg/cm2, and a 64-ms peak energy flux, measured from T0-0.204 s, of 2.47(-0.30,+0.58)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB170105_T22450/.