Photometric and Spectroscopic Studies of Type Ic Supernovae SN 2020akf and SN 2021mxx

Abstract We present a comprehensive analysis of optical photometry and medium-resolution spectroscopy for Type Ic supernovae (SNe) SN 2020akf and SN 2021mxx. Our study covers the evolution of SN 2020akf from −5 to 109 days and SN 2021mxx from −3 to 115 days relative to their B -band maximum. Their peak quasi-bolometric luminosities are estimated at log L bol max = 42.37 ± 0.02 erg s −1 and 42.21 ± 0.02 erg s −1 , respectively. The velocities of ejecta, derived from the Fe ii λ 5169 line at maximum light, are approximately 15,000 km s −1 for SN 2020akf and about 10,000 km s −1 for SN 2021mxx, which are consistent with those observed in other Type Ic SNe. Using the semianalytical Arnett model, we estimate that SN 2020akf has a kinetic energy of E k = 6.3 3 − 0.62 + 0.68 × 1 0 51 erg and an ejected mass of M ej = 4.7 1 − 0.46 + 0.50 M ⊙ , while for SN 2021mxx we get E k = 0.5 4 − 0.12 + 0.08 × 1 0 51 erg and M ej = 0.9 0 − 0.18 + 0.14 M ⊙ . The mass of 56 Ni synthesized in the explosion is estimated at 0.10 ± 0.02 M ⊙ for SN 2020akf and 0.05 ± 0.01 M ⊙ for SN 2021mxx. The metallicities of the host galaxies near the SN regions are ∼0.81 Z ⊙ for SN 2020akf and ∼0.76 Z ⊙ for SN 2021mxx, where Z ⊙ indicates solar metallicity. Our detailed analysis suggests that SN 2020akf falls into the category of a transitional Type Ic SN, having spectral properties between normal and broad-line Type Ic SNe, while SN 2021mxx is a normal Type Ic SN with an extremely low value of the M ej / E</jats