AstroNote 2025-305

We report the classification of four optical transients observed on 2025 October 22. Observations were performed on the Nordic Optical Telescope (NOT) at El Roque de Los Muchachos (La Palma, Spain) using the ALFOSC instrument with grism 4 as part of the 2025 NOT observing school at the University of Turku.

Classifications were done using SNID (Blondin & Tonry 2007 2007ApJ...666.1024B). AT 2025aaaa is reproduced well by a SN IIP spectrum and the light curve being in the early plateau-phase is consistent with this classification. AT 2025aasv and AT 2025aauv were well reproduced by spectra of normal Type Ia SNe, while AT 2025aavv gave good fit for both normal Ia and Ia-91T-like SNe before peak. The absolute magnitude of AT 2025aavv calculated for MJD=60969.2 in g-band is -19.1 mag, does not allow us to firmly confirm the subtype.

The redshifts of AT 2025aaaa, AT 2025aavv and AT 2025aavu are based on the spectral matches given by SNID as no host galaxy lines are clear in the spectra. For AT 2025aasv, the redshift was calculated from the Na ID absorption line clearly visible in the spectra.