TITLE: GCN CIRCULAR NUMBER: 28465 SUBJECT: IceCube-200916A - ZTF20acaapwk/SN2020tno classified as SN Ia DATE: 20/09/21 14:30:23 GMT FROM: Simeon Reusch at DESY Simeon Reusch, Robert Stein, Anna Franckowiak (DESY), Steve Schulze (WIS) and Jesper Sollerman (Stockholm University) report: We observed ZTF candidate ZTF20acaapwk/SN2020tno (Reusch et al., GCN 28441; see also Belkin et al., GCN 28453), a possible counterpart to high-energy neutrino IceCube-200916A (Blaufuss, GCN 28433), using the NOT+ALFOSC spectrograph on 21 September 2020. We classify SN2020tno as a type Ia supernova, thereby excluding any connection to IC200916A. ZTF20acaapwo/AT2020tnp remains a candidate. --- The data presented here were obtained with ALFOSC, which is provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOTSA.