EFFICIENT COSMIC RAY ACCELERATION, HYDRODYNAMICS, AND SELF-CONSISTENT THERMAL X-RAY EMISSION APPLIED TO SUPERNOVA REMNANT RX J1713.7–3946

By D. Ellison, D. Patnaude, P. Slane, J. C. Raymond. 2010

152 citations recorded by the source corpus.

We model the broadband emission from supernova remnant (SNR) RX J1713.7–3946 including, for the first time, a consistent calculation of thermal X-ray emission together with non-thermal emission in a nonlinear diffusive shock acceleration model. Our model tracks the evolution of the SNR including the plasma ionization state between the forward shock and the contact discontinuity. We use a plasma emissivity code to predict the thermal X-ray emission spectrum assuming the initially cold electrons are heated either by Coulomb collisions with the shock-heated protons (the slowest possible heating), or come into instant equilibration with the protons. For either electron heating model, electrons reach ≳107 K rapidly and the X-ray line emission near 1 keV is more than 10 times as luminous as the underlying thermal bremsstrahlung continuum. Since recent Suzaku observations show no detectable line emission, this places strong constraints on the unshocked ambient medium density and on the relativistic electron-to-proton ratio. For the uniform circumstellar medium (CSM) models that we consider, the low densities and high relativistic electron-to-proton ratios required to match the Suzaku X-ray observations definitively rule out pion decay as the emission process producing GeV–TeV photons. We show that leptonic models, where inverse-Compton scattering against the cosmic background radiation dominates the GeV–TeV emission, produce better fits to the broadband thermal and non-thermal observations in a uniform CSM.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/a2d292317d07cc71de0dc30020bbba65eaf80b0c

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In Astronomy and Astrophysics

1. Jeremiah P. Ostriker
2. T. Naab
3. E. Orlando
4. Tsuyoshi Inoue
5. J. Vink
6. Y. Fukui
7. Troy A. Porter
8. D. Caprioli

In Nuclear and High Energy Physics

1. E. Orlando
2. J. Vink
3. Troy A. Porter
4. Tsuyoshi Inoue
5. D. Caprioli
6. Y. Fukui
7. I. Grenier
8. S. Reynolds

Citations in the corpus

• TOWARD UNDERSTANDING THE COSMIC-RAY ACCELERATION AT YOUNG SUPERNOVA REMNANTS INTERACTING WITH INTERSTELLAR CLOUDS: POSSIBLE APPLICATIONS TO RX J1713.7−3946 (2011, background): “Spectrum of Hadronic Gamma Rays Recently, using one-dimensional model assuming a uniform ISM, Ellison et al. (2010) claimed that if we reduce the ambient density to reconcile the absence of the thermal X-ray line emission from RX J1713.”
• Observational Signatures of Particle Acceleration in Supernova Remnants (2012, background): “37, see Katz and Waxman, 2008; Ellison et al., 2010).”
• Theoretical Challenges in Galaxy Formation (2016, background): “The estimates mostly range between 5 and 30 % of the total supernova explosion energy (Ellison et al. 2010, Kang & Jones 2006) with increasingly fundmagental, ab initio calculations now being made (e.g. Caprioli, Pop & Spitkovsky 2015).”
• Strong evidence for hadron acceleration in Tycho’s supernova remnant (2011, background): “Its spectrum in the GeV band is in fact very flat (∝ E−1.5), as predicted by a ”leptonic” model, which is also supported by the lack of detection of thermal X-ray emission Ellison et al. (2010).”
• Magnetic Fields in Supernova Remnants and Pulsar-Wind Nebulae (2011, background): “The other two have much larger angular sizes and considerably more irregular morphologies (Slane et al. 1999, 2001); they also show no trace of thermal X-rays, putting severe upper limits on the presence of any thermal gas (Ellison et al. 2010).”
• OBSERVATIONS OF THE YOUNG SUPERNOVA REMNANT RX J1713.7−3946 WITH THE FERMI LARGE AREA TELESCOPE (2011, background): “Ellison et al. (2010) have331 performed calculations of thermal X-ray emission from shocked plasma with non-equilibrium332 ionization in the case of uniform ambient density, following a hydrodynamic evolution with333 which non-linear DSA theory is coupled; they found that the shocked gas densities…”
• The origin of galactic cosmic rays (2013, unknown): “Ellison et al. (2010) concluded that the emission is of leptonic origin.”
• Cosmic ray driven outflows in global galaxy disc models (2013, background): “Our fiducial choice of fCR = 0.3 is within the range often quoted (e.g. Wefel 1987; Kang & Jones 2006; Ellison et al. 2010); however, the precise value is not well known.”