Early Spectroscopy and Dense Circumstellar Medium Interaction in SN 2023ixf
Creators: name: Bostroem, K. Azalee
name: Pearson, Jeniveve
name: Shrestha, Manisha
name: Sand, David J.
name: Valenti, Stefano
name: Jha, Saurabh W.
name: Andrews, Jennifer E.
name: Smith, Nathan
name: Terreran, Giacomo
name: Green, Elizabeth
name: Dong, Yize
name: Lundquist, Michael
name: Haislip, Joshua
name: Hoang, Emily T.
name: Hosseinzadeh, Griffin
name: Janzen, Daryl
name: Jencson, Jacob E.
name: Kouprianov, Vladimir
name: Paraskeva, Emmy
name: Retamal, Nicolas E. Meza
name: Reichart, Daniel E.
name: Arcavi, Iair
name: Bonanos, Alceste Z.
name: Coughlin, Michael W.
name: Dobson, Ross
name: Farah, Joseph
name: Albany, Lluís
name: Gutiérrez, Claudia
name: Hawley, Suzanne
name: Hebb, Leslie
name: Hiramatsu, Daichi
name: Howell, D. Andrew
name: Iijima, Takashi
name: Ilyin, Ilya
name: Jhass, Kiran
name: McCully, Curtis
name: Moran, Sean
name: Morris, Brett M.
name: Mura, Alessandra C.
name: Müller-Bravo, Tomás
name: Munday, James
name: Newsome, Megan
name: Pabst, Maria Th.
name: Ochner, Paolo
name: Gonzalez, Estefania Padilla
name: Pastorello, Andrea
name: Pellegrino, Craig
name: Piscarreta, Lara
name: Ravi, Aravind P.
name: Reguitti, Andrea
name: Salo, Laura
name: Vinko, Jozsef
name: de Vos, Kellie
name: Wheeler, J. C.
name: Williams, G. Grant
name: Wyatt, Samuel
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present the optical spectroscopic evolution of SN~2023ixf seen in sub-night cadence spectra from 1.18 to 14 days after explosion. We identify high-ionization emission features, signatures of interaction with material surrounding the progenitor star, that fade over the first 7 days, with rapid evolution between spectra observed within the same night. We compare the emission lines present and their relative strength to those of other supernovae with early interaction, finding a close match to SN~2020pni and SN~2017ahn in the first spectrum and SN~2014G at later epochs. To physically interpret our observations we compare them to CMFGEN models with confined, dense circumstellar material around a red supergiant progenitor from the literature. We find that very few models reproduce the blended \NC{} emission lines observed in the first few spectra and their rapid disappearance thereafter, making this a unique diagnostic. From the best models, we find a mass-loss rate of $10^{-3}-10^{-2}$ \mlunit{}, which far exceeds the mass-loss rate for any steady wind, especially for a red supergiant in the initial mass range of the detected progenitor. These mass-loss rates are, however, similar to rates inferred for other supernovae with early circumstellar interaction. Using the phase when the narrow emission features disappear, we calculate an outer dense radius of circumstellar material $R_\mathrm{CSM, out}\sim5\times10^{14}~\mathrm{cm}$ and a mean circumstellar material density of $ρ=5.6\times10^{-14}~\mathrm{g\,cm^{-3}}$. This is consistent with the lower limit on the outer radius of the circumstellar material we calculate from the peak \Halpha{} emission flux, $R_\text{CSM, out}\gtrsim9\times10^{13}~\mathrm{cm}$.
description: Published in ApJL