Bright Type II Supernova 2023ixf in M101: A Quick Analysis of the Early-Stage Spectra and Near-Infrared Light Curves

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 M101, which were obtained from $t=1.7$ to $8.0$ d. Our first spectrum showed remarkable emission features of Balmer series, He~{\sc ii}, N~{\sc iii}, C~{\sc iv}, and N~{\sc iv} with a strong blue continuum. Compared with the SNe II showing flash-ionized features, we suggest that this SN could be categorized into the high-luminosity SNe II with a nitrogen/helium-rich circumstellar material (CSM), e.g., SNe 2014G, 2017ahn, and 2020pni. The H~{$\alpha$} emission line can be tentatively explained by a narrower component with a velocity of $<300$ km~s$^{-1}$ and a broader one with $\sim2200$ km~s$^{-1}$. The near-infrared light curves were well consistent with those of the another luminous SN 2017ahn, and its absolute magnitudes locate on the bright end in the luminosity distribution of SNe II. These observational facts support that SN 2023ixf is well consistent with high-luminosity SNe II showing evidences of a dense nitrogen/helium-rich CSM.