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

February 2024 • 2024ApJ...961..247S

Authors • Shrestha, Manisha • Pearson, Jeniveve • Wyatt, Samuel • Sand, David J. • Hosseinzadeh, Griffin • Bostroem, K. Azalee • Andrews, Jennifer E. • Dong, Yize • Hoang, Emily • Janzen, Daryl • Jencson, Jacob E. • Lundquist, Michael • Mehta, Darshana • Retamal, Nicolás Meza • Valenti, Stefano • Rastinejad, Jillian C. • Daly, Phil • Porter, Dallan • Hinz, Joannah • Self, Skyler • Weiner, Benjamin • Williams, G. Grant • Hiramatsu, Daichi • Howell, D. Andrew • McCully, Curtis • Gonzalez, Estefania Padilla • Pellegrino, Craig • Terreran, Giacomo • Newsome, Megan • Farah, Joseph • Itagaki, Koichi • Jha, Saurabh W. • Kwok, Lindsey • Smith, Nathan • Schwab, Michaela • Rho, Jeonghee • Yang, Yi

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.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2024ApJ...961..247S
• PDF https://iopscience.iop.org/article/10.3847/1538-4357/ad11e1/pdf
• PREPRINT http://arxiv.org/abs/2310.00162
• ELECTR https://doi.org/10.3847%2F1538-4357%2Fad11e1