TITLE: GCN CIRCULAR NUMBER: 45134 SUBJECT: IceCube-260708A: Observations with the Vera C. Rubin Observatory DATE: 26/07/10 19:24:52 GMT FROM: Robert David Stein at JSI <rdstein@umd.edu> Robert Stein (UMD/NASA GSFC/JSI), Sean MacBride (University of Zürich), Tiago Ribeiro, Lynne Jones, Angelo Fausti, Marina Pavlovic, Kris Mortensen, Jacqueline Seron Navarrete, Carlos Morales, Leanne Guy, Brian Stalder, Bob Blum (NSF-DOE Vera C Rubin Observatory), Erin Howard, Eric Bellm (University of Washington), Igor Andreoni (UNC Chapel Hill), Michael Coughlin (University of Minnesota), Antonella Palmese (Carnegie Mellon), Yousuke Utsumi (National Astronomical Observatory of Japan), Bruno Sanchez (CPPM - IN2P3), and Robert Lupton (Princeton), report on behalf of NSF-DOE Vera C Rubin Observatory: We observed the localization region of the high-energy neutrino event IceCube-260708A (Zegarelli et. al, GCN 45120) with the 9.6 square degree field of view LSST Camera mounted on the 8.4-m Simonyi Survey Telescope at the Vera C. Rubin Observatory [1]. The neutrino event met the pre-approved trigger criteria for neutrino follow-up with Rubin [2], and observations were conducted following the community-designed plan. The first night of observations consisted of exposures in u (30s), g (4x30s), r (30s) and z (30s). We started observations at 2026-07-10 02:48:12 UTC, approximately 33.5 hours after event time. These observations achieved the following single-visit median depths: u: 20.5 g: 22.8 (across four visits) r: 23.5 z: 22.1 Though the Legacy Survey of Space and Time (LSST) survey has now begun, template images are not yet available for most filters in this region of the sky. For the images acquired on the night of July 9, 2026, approximately 5000 alerts were generated from our z-band observations. While our automated alert system relies on production-quality templates to function autonomously, we have mobilized a specialized team of Rubin staff to process these images offline using lower quality templates that have been acquired in the region, but do not yet meet the standards for deployment to alert production. Any candidates will be reported to the community via GCN, and reported to TNS. Observations of the neutrino will continue as part of the community observing plan. We thank everyone in the Rubin Project and the wider Rubin Science Community who contributed to the success of these observations. This material is based upon work supported in part by the National Science Foundation through Cooperative Agreements AST-1258333 and AST-2241526 and Cooperative Support Agreements AST-1202910 and 2211468 managed by the Association of Universities for Research in Astronomy (AURA), and the Department of Energy under Contract No. DE-AC02-76SF00515 with the SLAC National Accelerator Laboratory managed by Stanford University. Additional Rubin Observatory funding comes from private donations, grants to universities, and in-kind support from LSST-DA Institutional Members. [1] Ivezić et al. (2019), https://arxiv.org/abs/0805.2366 [2] Andreoni et al. (2024), https://arxiv.org/abs/2411.04793 View this GCN Circular online at https://gcn.nasa.gov/circulars/45134. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...