Bright Type II supernova 2023ixf in M 101: A quick analysis of the early-stage spectra and near-infrared light curves

Abstract We present early-stage analyses of low-resolution (R = 1000) optical spectra and near-infrared light curves of the bright Type II supernova (SN II) 2023ixf in the notable nearby face-on spiral galaxy M 101, which were obtained from t = 1.7 to 8.0 d. Our first spectrum showed remarkable emission features of the Balmer series, He ii, N iii, C iv, and N iv with a strong blue continuum. Compared with the SNe II which show flash-ionized features, we suggest that this SN could be categorized as a high-luminosity SN II with a nitrogen/helium-rich circumstellar material (CSM), e.g., SNe 2014G, 2017ahn, and 2020pni. The Hα emission line can be tentatively explained by a narrower component with a velocity of