Early Hard X-Rays from the Nearby Core-collapse Supernova SN 2023ixf

We present NuSTAR observations of the nearby SN 2023ixf in M101 (d=6.9 Mpc) which provide earliest hard X-ray detection a non-relativistic stellar explosion to date at $\delta t\approx$4-d and t\approx$11-d. The spectra are well described by hot thermal bremsstrahlung continuum with $T>25 \rm{keV}$ shining through thick neutral medium hydrogen column that decreases time (initial $N_{\rm{Hint}}=2.6\times 10^{23} \rm{cm^{-2}}$). A prominent Fe K$\alpha$ emission line is clearly detected, similar other strongly interacting SNe such as SN2020jl. rapidly decreasing intrinsic absorption suggests presence dense but confined circumstellar (CSM). absorbed broadband luminosity (0.3--79 keV) $L_{X} \approx 2.5 \times 10^{40}$ erg s$^{-1}$ during both epochs, increase overall flux related decrease absorbing column. Interpreting these context radiation originating from interaction shock we infer large particle densities excess $n_{\rm{CSM}}\approx 4\times 10^{8} \rm{cm^{-3}}$ $r<10^{15} \rm{cm}$, corresponding an enhanced progenitor mass-loss rate $\dot M 3\times 10^{-4}$ M$_{\odot}$ yr$^{-1}$ for assumed wind velocity $v_w=50$ km s$^{-1}$.