Evidence of Weak Circumstellar Medium Interaction in the Type II SN 2023axu

• DOI: 10.3847/1538-4357/ad11e1
• Publication Date: 2024-01-31T11:33:24Z
• Authors: Manisha Shrestha; Jeniveve Pearson; Samuel Wyatt; David J. Sand; Griffin Hosseinzadeh; K. Azalee Bostroem; Jennifer E. Andrews; Yize 一泽 Dong 董; Emily Hoang; Daryl Janzen; Jacob E. Jencson; Michael Lundquist; Darshana Mehta; Nicolás Meza Retamal; Stefano Valenti; Jillian C. Rastin...; Phil Daly; Dallan Porter; Joannah Hinz; Skyler Self; Benjamin Weiner; G. Grant Williams; Daichi Hiramatsu; D. Andrew Howell; Curtis McCully; Estefania Padilla...; Craig Pellegrino; Giacomo Terreran; Megan Newsome; Joseph Farah; Koichi Itagaki; Saurabh W. Jha; Lindsey Kwok; Nathan Smith; Michaela Schwab; Jeonghee Rho; Yi Yang
• Keywords: Type II supernovae; High Energy Astrophysical Phenomena (astro-ph.HE); FOS: Physical sciences; Circumstellar matter; Astrophysics; 01 natural sciences; QB460-466; Red supergiant stars; Astrophysics - Solar and Stellar Astrophysics; Stellar mass loss; 0103 physical sciences; Core-collapse supernovae; Astrophysics - High Energy Astrophysical Phenomena; Solar and Stellar Astrophysics (astro-ph.SR)

Abstract We present high-cadence photometric and spectroscopic observations of SN 2023axu, a classical Type II supernova with an absolute V-band peak magnitude of –17.2 ± 0.1 mag. SN 2023axu was discovered by the Distance Less Than 40 Mpc (DLT40) survey within 1 day of the last nondetection in the nearby galaxy NGC 2283 at 13.7 Mpc. We modeled the early light curve using a recently updated shock cooling model that includes the effects of line blanketing and found the explosion epoch to be MJD 59971.48 ± 0.03 and the probable progenitor to be a red supergiant. The shock cooling model underpredicts the overall UV data, which point to a possible interaction with circumstellar material. This interpretation is further supported by spectral behavior. We see a ledge feature around 4600 Å in the very early spectra (+1.1 and +1.5 days after the explosion), which can be a sign of circumstellar interaction. The signs of circumstellar material are further bolstered by the presence of absorption features blueward of Hα and Hβ at day >40, which is also generally attributed to circumstellar interaction. Our analysis shows the need for high-cadence early photometric and spectroscopic data to decipher the mass-loss history of the progenitor.