Effect of Cosmic Rays on the Evolution and Momentum Deposition of Supernova Remnants

Diesing, Rebecca; Caprioli, Damiano

doi:10.1103/physrevlett.121.091101

Cited by 53 publications

(53 citation statements)

References 44 publications

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“…To further address the importance of the late times in SNR evolution for shaping the electron spectrum, we considered a rather extreme situation in which particle acceleration is efficient until 80 kyr. Indeed, it has been shown that the duration of the ST phase can be substantially extended, for instance because of the CR pressure on the SNR shock (Diesing & Caprioli 2018). In Fig.…”

Section: Resultsmentioning

confidence: 99%

“…In this work, we assume E SN = 10 51 erg, M ej = 1 M , and n 0 = 1 cm −3 as reference values for type Ia SNe. It is worth recalling that in the presence of efficient CR acceleration at the SNR shock, as discussed by Diesing & Caprioli (2018), the evolution in time of the shock in the final stages of the evolution may be affected rather remarkably by the CR pressure, and the beginning of the radiative phase may be delayed. We do not include these effects here.…”

Section: Evolution Of the Shock In The Circumstellar Environmentmentioning

confidence: 99%

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Cosmic ray protons and electrons from supernova remnants

Cristofari

Blasi

Caprioli

2021

A&A

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Context. The spectrum of cosmic ray protons and electrons released by supernova remnants throughout their evolution is poorly known because of the difficulty in accounting for particle escape and confinement downstream of a shock front, where both adiabatic and radiative losses are present. Since electrons lose energy mainly through synchrotron losses, it is natural to ask whether the spectrum released into the interstellar medium may be different from that of their hadronic counterpart. Independent studies of cosmic ray transport through the Galaxy require that the source spectrum of electrons and protons be very different. Therefore, the above question acquires a phenomenological relevance. Aims. Here we calculate the spectrum of cosmic ray protons released during the evolution of supernovae of different types, accounting for the escape from the upstream region and for adiabatic losses of particles advected downstream of the shock and liberated at later times. The same calculation is carried out for electrons, where in addition to adiabatic losses we take the radiative losses suffered behind the shock into account. These electrons are dominated by synchrotron losses in the magnetic field, which most likely is self-generated by cosmic rays accelerated at the shock. Methods. We use standard temporal evolution relations for supernova shocks expanding in different types of interstellar media together with an analytic description of particle acceleration and magnetic field amplification to determine the density and spectrum of cosmic ray particles. Their evolution in time is derived by numerically solving the equation describing advection with adiabatic and radiative losses for electrons and protons. The flux from particles continuously escaping the supernova remnants is also accounted for. Results. The magnetic field in the post-shock region is calculated by using an analytic treatment of the magnetic field amplification due to nonresonant and resonant streaming instability and their saturation. The resulting field is compared with the available set of observational results concerning the dependence of the magnetic field strength upon shock velocity. We find that when the field is the result of the growth of the cosmic-ray-driven nonresonant instability alone, the spectrum of electrons and protons released by a supernova remnant are indeed different; however, such a difference becomes appreciable only at energies ≳100−1000 GeV, while observations of the electron spectrum require such a difference to be present at energies as low as ∼10 GeV. An effect at such low energies requires substantial magnetic field amplification in the late stages of supernova remnant evolution (shock velocity ≪1000 km s−1); this may not be due to streaming instability but rather hydrodynamical processes. We comment on the feasibility of such conditions and speculate on the possibility that the difference in spectral shape between electrons and protons may reflect either some unknown acceleration effect or additional energy losses in cocoons around the sources.

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Section: Resultsmentioning

confidence: 99%

Section: Evolution Of the Shock In The Circumstellar Environmentmentioning

confidence: 99%

Cosmic ray protons and electrons from supernova remnants

Cristofari

Blasi

Caprioli

2021

A&A

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“…For example magnetic fields, cosmic rays (e.g. Diesing & Caprioli 2018;Gupta et al 2018) and thermal conduction (e.g. Keller et al 2014;El-Badry et al 2019) change their evolution.…”

Section: Introductionmentioning

confidence: 99%

Hot phase generation by supernovae in ISM simulations: resolution, chemistry, and thermal conduction

Steinwandel

Moster

Naab

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Supernovae (SN) generate hot gas in the interstellar medium (ISM), help setting the ISM structure and support the driving of outflows. It is important to resolve the hot gas generation for galaxy formation simulations at solar mass and sub-parsec resolution which realise individual supernova (SN) explosions with ambient densities varying by several orders of magnitude in a realistic multi-phase ISM. We test resolution requirements by simulating SN blast waves at three metallicities (Z = 0.01, 0.1 and 1Z ), six densities and their respective equilibrium chemical compositions (n = 0.001 cm −3 -100 cm −3 ), and four mass resolutions (0.1 -100 M ). We include non-equilibrium cooling and chemistry, a homogenous interstellar radiation field, and shielding with a modern pressure-energy smoothed particle hydrodynamics (SPH) method including isotropic thermal conduction and a meshless-finite-mass (MFM) solver. We find stronger resolution requirements for chemistry and hot phase generation than for momentum generation. While at 10 M the radial momenta at the end of the Sedov phase start converging, the hot phase generation and chemistry require higher resolutions to represent the neutral to ionised hydrogen fraction at the end of the Sedov phase correctly. Thermal conduction typically reduces the hot phase by 0.2 dex and has little impact on the chemical composition. In general, our 1, and 0.1 M results agree well with previous numerical and analytic estimates. We conclude that for the thermal energy injection SN model presented here resolutions higher than 10 M are required to model the chemistry, momentum and hot phase generation in a multi-phase ISM.

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“…Remnant Evolution-SNRs are evolved using the formalism described in [20]. More specifically, SNR evolution can be understood in terms of four stages: the ejecta-dominated stage, in which the mass of the sweptup ambient medium is less than that of the SN ejecta, the Sedov stage, in which the swept-up mass dominates the total mass and the SNR expands adiabatically, the pressure-driven snowplow, in which the remnant cools due to forbidden atomic transitions but continues to expand because its internal pressure exceeds the ambient arXiv:1905.07414v2 [astro-ph.HE] 26 Jul 2019 pressure, and, finally, the momentum-driven snowplow, in which the internal pressure falls below the ambient pressure and expansion continues due to momentum conservation.…”

mentioning

confidence: 99%

Spectrum of Electrons Accelerated in Supernova Remnants

Diesing

Caprioli

2019

Phys. Rev. Lett.

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Using a semi-analytic model of non-linear diffusive shock acceleration, we model the total spectrum of cosmic ray (CR) electrons accelerated by supernova remnants (SNRs). Because electrons experience synchrotron losses in the amplified magnetic fields characteristic of SNRs, they exhibit substantially steeper spectra than protons. In particular, we find that the difference between the electron and proton spectral index (power law slope) ranges from 0.1 to 0.4. Our findings must be reckoned with theories of Galactic CR transport, which often assume that electrons and protons are injected with the same slope, and may especially have implications for the observed "positron excess."

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Effect of Cosmic Rays on the Evolution and Momentum Deposition of Supernova Remnants

Cited by 53 publications

References 44 publications

Cosmic ray protons and electrons from supernova remnants

Cosmic ray protons and electrons from supernova remnants

Hot phase generation by supernovae in ISM simulations: resolution, chemistry, and thermal conduction

Spectrum of Electrons Accelerated in Supernova Remnants

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