Early hard X-rays from the nearby core-collapse supernova SN2023ixf

Understand

We present NuSTAR observations of the nearby SN 2023ixf in M101 (d=6.9 Mpc) which provide the earliest hard X-ray detection of a non-relativistic stellar explosion to date at $\delta t\approx$4-d and $\delta t\approx$11-d.

• The spectra are well described by a hot thermal bremsstrahlung continuum with $T>25 \rm{keV}$ shining through a thick neutral medium with a neutral hydrogen column that decreases with time (initial $N_{\rm{Hint}}=2.6\times 10^{23} \rm{cm^{-2}}$).
• A prominent neutral Fe K$\alpha$ emission line is clearly detected, similar to other strongly interacting SNe such as SN2020jl.
• The rapidly decreasing intrinsic absorption with time suggests the presence of a dense but confined circumstellar medium (CSM).