SN 2023ixf in Messier 101: Photo-ionization of Dense, Close-in Circumstellar Material in a Nearby Type II Supernova

Journal article

International audienceAbstract We present UV and/or optical observations and models of SN 2023ixf, a type II supernova (SN) located in Messier 101 at 6.9 Mpc. Early time ( flash ) spectroscopy of SN 2023ixf, obtained primarily at Lick Observatory, reveals emission lines of H i , He i/ii , C iv , and N iii/iv/v with a narrow core and broad, symmetric wings arising from the photoionization of dense, close-in circumstellar material (CSM) located around the progenitor star prior to shock breakout. These electron-scattering broadened line profiles persist for ∼8 days with respect to first light, at which time Doppler broadened the features from the fastest SN ejecta form, suggesting a reduction in CSM density at r ≳ 10 15 cm. The early time light curve of SN 2023ixf shows peak absolute magnitudes (e.g., M u = −18.6 mag, M g = −18.4 mag) that are ≳2 mag brighter than typical type II SNe, this photometric boost also being consistent with the shock power supplied from CSM interaction. Comparison of SN 2023ixf to a grid of light-curve and multiepoch spectral models from the non-LTE radiative transfer code CMFGEN and the radiation-hydrodynamics code HERACLES suggests dense, solar-metallicity CSM confined to r = (0.5–1) × 10 15 cm, and a progenitor mass-loss rate of M ̇ = 10 − 2 M ⊙ yr −1 . For the assumed progenitor wind velocity of v w = 50 km s −1 , this corresponds to enhanced mass loss (i.e., superwind phase) during the last ∼3–6 yr before explosion

Authors: Jacobson-Galán, WV; Dessart, L; Margutti, R; Chornock, R; Foley, RJ

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Astronomical Society
• Journal: The Astrophysical Journal Letters
• Volume: 954
• Issue: 2
• Pages: L42-L42
• Publication date: 2023-09-08
• DOI: 10.3847/2041-8213/acf2ec
• EISSN: 2041-8213
• ISSN: 2041-8205
• Language: English
• Keywords: Supernova; Stars; Type II supernova; Astrophysics; Physics; Ejecta; Light curve; Metallicity