SN 2023xqm: A gradually fading Ia supernova exhibiting isolated high-velocity signatures

We conducted an exhaustive analysis combining optical photometry and spectroscopy of the type Ia supernova designated SN 2023xqm. Our observational period spanned from the two weeks preceding to 88 days after the B -band peak luminosity time. We determined the peak brightness in the B -band to be −18.90 ± 0.50 mag, and it is accompanied by a moderately slow decay rate of 0.90 ± 0.07 mag. The maximum quasi-bolometric luminosity was estimated to be 1.52 × 10 43 erg s −1 and correlated with a calculated 56 Ni mass of 0.74 ± 0.05 M ⊙ , aligning with the modestly reduced rate of light curve decay. A plateau that can be observed in the r − i color curve might correlate with the minor elevation noted between the principal and secondary peaks of the i -band light curve. An initial spectral analysis of SN 2023xqm revealed distinct high-velocity features (HVFs) in Ca II that contrast with the subdued HVFs observed in Si II . Such attributes may stem from variations in ionization or temperature or from scenarios involving enhanced element abundance, suggesting a naturally lower photospheric temperature for SN 2023xqm, which could be indicative of incomplete burning during the white dwarf’s detonation. The observed traits in the light curve and the spectral features offer significant insights into the variability among type Ia supernovae and their explosion dynamics.