Strong evidence for hadron acceleration in Tycho's supernova remnant

260Citations
Citations of this article
40Readers
Mendeley users who have this article in their library.

Abstract

Context. Very recent gamma-ray observations of G120.1+1.4 (Tycho's) supernova remnant (SNR) by Fermi-LAT and VERITAS have provided new fundamental pieces of information for understanding particle acceleration and nonthermal emission in SNRs. Aims. We want to outline a coherent description of Tycho's properties in terms of SNR evolution, shock hydrodynamics, and multiwavelength emission by accounting for particle acceleration at the forward shock via first-order Fermi mechanism. Methods. We adopt here a quick and reliable semi-analytical approach to nonlinear diffusive shock acceleration. It includes magnetic field amplification due to resonant streaming instability and the dynamical backreaction on the shock of both cosmic rays (CRs) and self-generated magnetic turbulence. Results. We find that Tycho's forward shock accelerates protons up to at least 500 TeV, channelling into CRs about 10% of its kinetic energy. Moreover, the CR-induced streaming instability is consistent with all the observational evidence of very efficient magnetic field amplification (up to -300 μG). In such a strong magnetic field, the velocity of the Alfvén waves scattering CRs in the upstream is expected to be enhanced and to make accelerated particles feel an effective compression factor lower than 4, in turn leading to an energy spectrum steeper than the standard prediction E -2. This effect is crucial for explaining GeV-to-TeV gamma-ray spectrum as the result of neutral pions decay produced in nuclear collisions between accelerated nuclei and the background gas. Conclusions. The self-consistency of such hadronic scenario, along with the inability of the concurrent leptonic mechanism (inverse Compton scattering of relativistic electrons on several photon backgrounds) to reproduce both the shape and the normalization of the detected gamma-ray emission, represents the first clear and direct radiative evidence that hadron acceleration occurs efficiently in young Galactic SNRs. © ESO, 2012.

References Powered by Scopus

RADIATIVE PROCESSES IN ASTROPHYSICS

2886Citations
N/AReaders
Get full text

The acceleration of cosmic rays in shock fronts - I

0
1887Citations
N/AReaders
Get full text

Particle acceleration at astrophysical shocks: A theory of cosmic ray origin

1724Citations
N/AReaders
Get full text

Cited by Powered by Scopus

Detection of the characteristic pion-decay signature in supernova remnants

720Citations
N/AReaders
Get full text

Simulations of ion acceleration at non-relativistic shocks. i. acceleration efficiency

451Citations
N/AReaders
Get full text

The origin of galactic cosmic rays

432Citations
N/AReaders
Get full text

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Cite

CITATION STYLE

APA

Morlino, G., & Caprioli, D. (2012). Strong evidence for hadron acceleration in Tycho’s supernova remnant. Astronomy and Astrophysics, 538. https://doi.org/10.1051/0004-6361/201117855

Readers' Seniority

Tooltip

PhD / Post grad / Masters / Doc 18

67%

Researcher 8

30%

Professor / Associate Prof. 1

4%

Readers' Discipline

Tooltip

Physics and Astronomy 27

90%

Sports and Recreations 1

3%

Engineering 1

3%

Chemistry 1

3%

Save time finding and organizing research with Mendeley

Sign up for free