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

Abstract

SN 2023ixf, recently reported in the nearby galaxy M101 at a distance of $6.85\mathrm{Mpc}$, 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 $3\times 10^{43}\mathrm{erg}{\mathrm{s}}^{-1}$ at 3.9 days after the explosion and fully settled onto the radioactive tail at $\sim 90$ days. The effective temperature decreased from $3.2\times 10^4\mathrm{K}$ at the first observation and approached to a constant of $\sim (3000-4000)\mathrm{K}$ after the first two months. The evolution of the photospheric radius is consistent with a homologous expansion with a velocity of $8700\mathrm{km}{\mathrm{s}}^{-1}$ in the first two months, and it shrunk subsequently. Based on the radioactive tail, the initial nickel mass is about $M_{\mathrm{Ni}}\sim 0.098M_{\odot }$. The explosion energy and the ejecta mass are estimated to be $E\simeq (1.0-5.7)\times 10^{51}\mathrm{erg}$ and $M_{\mathrm{ej}}\simeq (3.8-16)M_{\odot }$, 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 $M_{\mathrm{CSM}}\sim 0.013M_{\odot }$, a CSM density of $\ddot{I}{}_{\mathrm{CSM}}\sim 2.5\times 10^{-13}\mathrm{g}\mathrm{c}{\mathrm{m}}^{-3}$ and a mass loss rate of the progenitor of $\dot{M}\sim 0.022M_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$.

15 pages, 7 figures, 3 tables. Accepted for publication in ApJ. Comments welcome!