AstroNote 2026-25

We report optical spectroscopic classifications of SN2026cff as a young Type II SN. The spectrum shows a blue continuum with a few emission features. The emission line near 6644 Å is consistent with Halpha considering the host galaxy redshift (NGC 3660) of z = 0.0122. We also identify a broader feature near 4600 Å, which could be due to a blend of He II, C III and N III lines. GELATO (Harutyunyan et al. 2008 2008A&A...488..383H) classification returns a match with the early phases of the Type II SN 1999gi. The spectrum also resembles the early phases of the Type II SN 2016esw. 

Observations were performed on the ESO New Technology Telescope (NTT) at La Silla at UT 2026-02-07T08:26:34, using EFOSC2 with Grism 11 (3380-7520A, 16A resolution). The spectrum was taken nearly one day after ZTF discovery (06 Feb 2026 08:05:04 UTC) and probably a few days after explosion given the last ZTF non-detection (02 Feb 2026 10:41:16 UT).

Targets were supplied by ATLAS (Tonry et al. 2018 2018PASP..130f4505T), the Zwicky Transient Facility ZTF (Bellm et al. 2019 2019PASP..131a8002B) - data stream processed by the ALeRCE broker (Forster et al. 2020 2021AJ....161..242F).

Observations were conducted in the context of the ESO La Silla Observing School 2026. Follow-up observations in both optical and IR wavelengths are highly encouraged.