Multiband Simultaneous Photometry of Type II SN 2023ixf with Mephisto and the Twin 50-cm Telescopes

SN 2023ixf, recently reported in the nearby galaxy M101 at a distance of 6.85~ Mpc, was one of the closest and brightest core-collapse supernovae (CCSNe) in the last decade. In this work, we present multi-wavelength photometric observation of SN 2023ixf with the Multi-channel Photometric Survey Telescope (Mephisto) in $uvgr$ bands and with the twin 50-cm telescopes in $griz$ bands. We find that the bolometric luminosity reached the maximum value of 3×10⁴³~ erg~s⁻¹ at 3.9 days after the explosion and fully settled onto the radioactive tail at ~90 days. The effective temperature decreased from 3.2×10⁴~ K at the first observation and approached to a constant of ~(3000-4000)~ K after the first two months. The evolution of the photospheric radius is consistent with a homologous expansion with a velocity of 8700~ km~s⁻¹ in the first two months, and it shrunk subsequently. Based on the radioactive tail, the initial nickel mass is about MNi~ 0.098M_. The explosion energy and the ejecta mass are estimated to be E(1.0-5.7)×10⁵¹~ erg and Mₑⱼ(3.8-16)M_, respectively. The peak bolometric luminosity is proposed to be contributed by the interaction between the ejecta and the circumstellar medium (CSM). We find a shocked CSM mass of MCSM~0.013M_, a CSM density of ρCSM~2.5×10⁻¹³~ g~cm⁻³ and a mass loss rate of the progenitor of M~0.022M_~ yr⁻¹.