The Preexplosion Environments and the Progenitor of SN 2023ixf from the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX)

Abstract

Supernova (SN) 2023ixf was discovered on 2023 May 19. The host galaxy, M101, was observed by the Hobby–Eberly Telescope Dark Energy Experiment collaboration over the period 2020 April 30–2020 July 10, using the Visible Integral-field Replicable Unit Spectrograph (3470 ≲ λ ≲ 5540 Å) on the 10 m Hobby–Eberly Telescope. The fiber filling factor within ±30″ of SN 2023ixf is 80% with a spatial resolution of 1″. The r < 5.″5 surroundings are 100% covered. This allows us to analyze the spatially resolved preexplosion local environments of SN 2023ixf with nebular emission lines. The two-dimensional maps of the extinction and the star formation rate (SFR) surface density (Σ _SFR ) show weak increasing trends in the radial distributions within the r < 5.″5 regions, suggesting lower values of extinction and SFR in the vicinity of the progenitor of SN 2023ixf. The median extinction and that of the surface density of SFR within r < 3″ are E ( B − V ) = 0.06 ± 0.14, and ${{\rm{\Sigma }}}_{\mathrm{SFR}}={10}^{-5.44\pm 0.66}\,{M}_{\odot }\,{\mathrm{yr}}^{-1}\,{\mathrm{arcsec}}^{-2}.$ There is no significant change in extinction before and after the explosion. The gas metallicity does not change significantly with the separation from SN 2023ixf. The metal-rich branch of the R _23 calculations indicates that the gas metallicity around SN 2023ixf is similar to the solar metallicity (∼ Z _☉ ). The archival deep images from the Canada–France–Hawaii Telescope Legacy Survey (CFHTLS) show a clear detection of the progenitor of SN 2023ixf in the z band at 22.778 ± 0.063 mag, but nondetections in the remaining four bands of CFHTLS ( u , g , r , i ). The results suggest a massive progenitor of ≈22 M _☉ .

Keywords

• Supernovae