Nonthermal radiation of young supernova remnants: the case of Cas A

Abstract

The processes responsible for the broad-band radiation of the young supernova remnant Cas A are explored using a new code which is designed for a detailed treatment of the diffusive shock acceleration of particles in nonlinear regime. The model is based on spherically symmetric hydrodynamic equations complemented with transport equations for relativistic particles. Electrons, protons and the oxygen ions accelerated by forward and reverse shocks are included in the numerical calculations. We show that the available multi-wavelength observations in the radio, X-ray and gamma-ray bands can be best explained by invoking particle acceleration by both forward and reversed shocks. Although the TeV gamma-ray observations can be interpreted by interactions of both accelerated electrons and protons/ions, the measurements by Fermi LAT at energies below 1 GeV give a tentative preference to the hadronic origin of gamma-rays. Then, the acceleration efficiency in this source, despite the previous claims, should be very high; 25% of the explosion energy (or approximately $3\cdot 10^{50}$ erg) should already be converted to cosmic rays, mainly by the forward shock. At the same time, the model calculations do not provide extension of the maximum energy of accelerated protons beyond 100 TeV. In this model, the acceleration of electrons is dominated by the reverse shock; the required $10^{48}$ erg can be achieved under the assumption that the injection of electrons (positrons) is supported by the radioactive decay of ${}^{44}$Ti.

28 pages, 14 figures, 3 tables, submitted to ApJ

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Cited by in corpus (28)

• Modeling SNR Cassiopeia A from the Supernova Explosion to its Current Age: The role of post-explosion anisotropies of ejecta
• A cut-off in the TeV gamma-ray spectrum of the SNR Cassiopeia A
• Magnetic field amplification in nonlinear diffusive shock acceleration including resonant and non-resonant cosmic-ray driven instabilities
• Type IIn supernovae as sources of high energy astrophysical neutrinos
• Evidence for proton acceleration up to TeV energies based on VERITAS and Fermi-LAT observations of the Cas A SNR
• Locating the most energetic electrons in Cassiopeia A
• On the shape of the gamma-ray spectrum around the "${\pi }^0$-bump"
• Dust survival rates in clumps passing through the Cas A reverse shock -- II. The impact of magnetic fields
• Non-thermal emission from the reverse shock of the youngest galactic Supernova remnant G1.9+0.3
• Spectral softening in core-collapse supernova remnant expanding inside wind-blown bubble
• Fast radio bursts by high-frequency synchrotron maser emission generated at the reverse shock of a powerful magnetar flare
• Uncovering magnetic turbulence in young supernova remnants with polarized X-ray imaging
• On the energy distribution of relativistic electrons in the young supernova remnant G1.9+0.3
• Expectation on Observation of Supernova Remnants with the LHAASO Project
• SNR G39.2-0.3, an Hadronic Cosmic Rays Accelerator
• Is Supernova Remnant Cassiopeia A a PeVatron?
• Multi-Year X-ray Variations of Iron-K and Continuum Emissions in the Young Supernova Remnant Cassiopeia A
• A Self-Consistent Explanation of TeV Emissions from HESS J1640-465 and HESS J1641-463
• Evidence for gamma-ray emission from the remnant of Kepler's supernova based on deep H.E.S.S. observations
• New estimation of the nuclear de-excitation line emission from the supernova remnant Cassiopeia A
• A Possible Hadronic Origin of TeV Photon Emission from SNR G106.3+2.7
• On the Origin of the Gamma-Ray Emission toward SNR CTB 37A with $Fermi$-LAT
• ATCA Study of Small Magellanic Cloud Supernova Remnant 1E 0102.2-7219
• Gamma-Ray Emission from Supernova Remnants and Surrounding Molecular Clouds
• Gamma-ray Emission of the Kes 73/1E 1841-045 Region Observed with the Fermi Large Area Telescope
• Reverse-Shock in Tycho's Supernova Remnant
• A Study of Radio Knots within Supernova Remnant Cassiopeia A
• An Asymmetrical Model for High Energy Radiation of Cassiopeia A