Early Hard X-Rays from the Nearby Core-collapse Supernova SN 2023ixf
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1.
California Institute of Technology
Abstract
We present NuSTAR observations of the nearby SN 2023ixf in M101 (d = 6.9 Mpc) that provide the earliest hard X-ray detection of a nonrelativistic stellar explosion to date at δt ≈ 4 days and δt ≈ 11 days. The spectra are well described by a hot thermal bremsstrahlung continuum with T > 25 keV shining through a thick neutral medium with a neutral hydrogen column that decreases with time (initial NHint = 2.6 × 1023 cm−2). A prominent neutral Fe Kα emission line is clearly detected, similar to other strongly interacting supernovae (SNe) such as SN 2010jl. The rapidly decreasing intrinsic absorption with time suggests the presence of a dense but confined circumstellar medium (CSM). The absorbed broadband X-ray luminosity (0.3–79 keV) is LX ≈ 2.5 × 1040 erg s−1 during both epochs, with the increase in overall X-ray flux related to the decrease in the absorbing column. Interpreting these observations in the context of thermal bremsstrahlung radiation originating from the interaction of the SN shock with a dense medium we infer large particle densities in excess of nCSM ≈ 4 × 108 cm−3 at r < 1015 cm, corresponding to an enhanced progenitor mass-loss rate of Ṁ ≈ 3 × 10⁻⁴ M⊙ yr−1 for an assumed wind velocity of vw = 50 km s−1.
Copyright and License
© 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
We thank the anonymous referee for comments and helping to clarify the results in this Letter. This work makes use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). This research has made use of data and/or software provided by the High Energy Astrophysics Science Archive Research Center (HEASARC), which is a service of the Astrophysics Science Division at NASA/GSFC.
B.G., M.B., H.E., and F.H. acknowledge support under NASA Contract No. NNG08FD60C. R.M. acknowledges support by the National Science Foundation under Award Nos. AST-2221789 and AST-2224255.
Facilities
NuSTAR - The NuSTAR (Nuclear Spectroscopic Telescope Array) mission, Swift(XRT) - Swift Gamma-Ray Burst Mission
Software References
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Additional details
- ISSN
- 2041-8213
- NNG08FD60C
- National Aeronautics and Space Administration
- AST-2221789
- National Science Foundation
- AST-2224255
- National Science Foundation
- Caltech groups
- Astronomy Department, Space Radiation Laboratory, NuSTAR