TITLE: GCN CIRCULAR NUMBER: 41541 SUBJECT: LIGO/Virgo/KAGRA S250818k: nature of the AT2025ulz/ZTF25abjmnnps OT DATE: 25/08/25 13:17:47 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V.M. Lipunov, (Lomonosov MSU), In several recent telegrams (GCN 41532, 41538) the nature of the AT2025ulz/ZTF25abjmnps source is discussed. An alternative between the KN and SN II models has emerged. The unusual observable properties of the optical flare are emphasized. This alternative seems strange. For example, where can SN II appear in an elliptical galaxy? In this regard, I propose to include a third possible model, namely the merger of two heavy white dwarfs (O-Ne-Mg dwarfs) turning into a neutron star - a dumbbell with powerful radiation of gravitational waves [1]. As was shown earlier, such a phenomenon can generate an unusual form of gravitational wave impulse, which can be taken for a phenomenon caused by a terrestrial artifact. Is this not related to the fact that the initial probability of a terrestrial nature turned out to be more than 70%? [1] Lipunov V.M., Double O-Ne-Mg white dwarfs merging as the source of the powerful gravitational waves for LIGO/VIRGO type interferometers., New Astronomy, Volume 56, p. 84-85, 2017 https://doi.org/10.1016/j.newast.2017.04.013 View this GCN Circular online at https://gcn.nasa.gov/circulars/41541. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...