Alfvén wave amplification and self-containment of cosmic rays escaping from a supernova remnant

Fujita, Yutaka; Takahara, Fumio; Ohira, Yutaka; Iwasaki, Kazunari

doi:10.1111/j.1365-2966.2011.18980.x

Cited by 34 publications

(35 citation statements)

References 28 publications

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“…Theoretically, this phenomenon is also studied by Monte Carlo simulation, in which the CR streaming instability can generate Alfvén waves. The waves strongly scatter the particles and make the particle diffusion in the ISM around the SNR remarkably slow, and the diffusion coefficient is therefore strongly suppressed (Fujita, Ohira & Takahara 2010; Fujita et al 2011). This kind of suppression is significant if the ambient ISM is well ionized for the CRs around the SNRs, because the neutral damping of Alfvén waves is not effective.…”

Section: Discussion and Summarymentioning

confidence: 99%

γ-rays from molecular clouds illuminated by accumulated diffusive protons - II. Interacting supernova remnants

Li¹,

Chen²

2012

Monthly Notices of the Royal Astronomical Society

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Recent observations reveal that spectral breaks at ∼GeV are commonly present in Galactic γ‐ray supernova remnants (SNRs) interacting with molecular clouds and that most of them have a spectral (E2dF/dE) ‘platform’ extending from the break to lower energies. In Paper I, we developed an accumulative diffusion model by considering an accumulation of the diffusive protons escaping from the shock front throughout the history of the SNR expansion. In this paper, we improve the model by incorporating the finite volume of molecular clouds, demonstrate the model dependence on particle diffusion parameters and cloud size, and apply it to nine interacting SNRs (W28, W41, W44, W49B, W51C, Cygnus Loop, IC443, CTB 37A and G349.7+0.2). This refined model naturally explains the GeV spectral breaks and, in particular, the ‘platforms’, together with available TeV data. We find that the index of the diffusion coefficient δ is in the range 0.5–0.7, similar to the Galactic averaged value, and the diffusion coefficient for cosmic rays around the SNRs is essentially two orders of magnitude lower than the Galactic average (χ∼ 0.01), which is a good indication for the suppression of cosmic‐ray diffusion near SNRs.

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Section: Discussion and Summarymentioning

confidence: 99%

γ-rays from molecular clouds illuminated by accumulated diffusive protons - II. Interacting supernova remnants

Li¹,

Chen²

2012

Monthly Notices of the Royal Astronomical Society

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“…They concluded that only a rather small diffusion coefficient, ∼100 times lower A56, page 6 of 8 than the Galactic one, and a short distance from the SNR, of about 40 pc, could reconcile the detection of TeV emission, the GeV upper limits at the location of the HESS source, and the cloud mass derived by Paron & Giacani (2010). Nevertheless, given the small projected distance of ∼5 pc (at a distance of 3.6 kpc) between the cloud and the SNR, plus the fact that close to SNR shocks particle propagation may be significantly slowed down (Fujita et al 2011;Malkov et al 2013), the connection between the TeV emission and the SNR cannot be discarded. In fact, new calculations modelling the interaction between the SNR cosmic rays and the cloud, using the distance of 3.6 kpc, relax the conditions on the diffusion coefficient and cloud mass, making this possibility more likely than previously thought (see discussion in Zhu et al 2013).…”

Section: Discussionmentioning

confidence: 99%

Deep GMRT radio observations and a multi-wavelength study of the region around HESS J1858+020

Paredes¹,

Ishwara‐Chandra²,

Bosch‐Ramon³

et al. 2013

A&A

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Context. There are a number of very high energy sources in the Galaxy that remain unidentified. Multi-wavelength and variability studies, and catalogue searches, are powerful tools to identify the physical counterpart, given the uncertainty in the source location and extension. Aims. This work carries out a thorough multi-wavelength study of the unidentified, very high energy source HESS J1858+020 and its environs. Methods. We have performed Giant Metrewave Radio Telescope observations at 610 MHz and 1.4 GHz to obtain a deep, low-frequency radio image of the region surrounding HESS J1858+020. We analysed archival radio, infrared, and X-ray data as well. This observational information, combined with molecular data, catalogue sources, and a nearby Fermi gamma-ray detection of unidentified origin, are combined to explore possible counterparts to the very high energy source. Results. We provide with a deep radio image of a supernova remnant that might be related to the GeV and TeV emission in the region.We confirm the presence of an H ii region next to the supernova remnant and coincident with molecular emission. A potential region of star formation is also identified. We identify several radio and X-ray sources in the surroundings. Some of these sources are known planetary nebulae, whereas others may be non-thermal extended emitters and embedded young stellar objects. Three old, background Galactic pulsars also neighbour HESS J1858+020 along the line of sight. Conclusions. The region surrounding HESS J1858+020 is rich in molecular structures and non-thermal objects that may potentially be linked to this unidentified very high energy source. In particular, a supernova remnant interacting with nearby molecular clouds may be a good candidate, but a star forming region, or a non-thermal radio source of yet unclear nature, may also be behind the gamma-ray source. The neighbouring pulsars, despite being old and distant, cannot be discarded as candidates. Further observational studies are needed, however, to narrow the search for a counterpart to the HESS source.

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“…(56-57) but different assumptions are made regarding geometry of particle escape from the source (see (i) above), the character and strength of wave damping Γ (iv), and the role of quasilinear wave saturation (iii). Fujita et al (2011) and Yan et al (2012) utilize the isotropic escape models (in this case ∂/∂z should be replaced by ∂/∂r, etc.) while Ptuskin et al (2008) and Malkov et al (2012a) assume that particles propagate predominantly along the local large-scale field.…”

Section: Self-confinement Of Crs Near Their Acceleration Sitesmentioning

confidence: 99%

Microphysics of Cosmic Ray Driven Plasma Instabilities

et al. 2013

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Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic fields. In this review we discuss mechanisms of magnetic field amplification due to instabilities induced by CRs. We derive CR kinetic and magnetohydrodynamic equations that govern cosmic plasma systems comprising the thermal background plasma, comic rays and fluctuating magnetic fields to study CR-driven instabilities. Both resonant and non-resonant instabilities are reviewed, including the Bell short-wavelength instability, and the firehose instability. Special attention is paid to the longwavelength instabilities driven by the CR current and pressure gradient. The helicity production by the CR current-driven instabilities is discussed in connection with the dynamo mechanisms of cosmic magnetic field amplification.

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Alfvén wave amplification and self-containment of cosmic rays escaping from a supernova remnant

Cited by 34 publications

References 28 publications

γ-rays from molecular clouds illuminated by accumulated diffusive protons - II. Interacting supernova remnants

γ-rays from molecular clouds illuminated by accumulated diffusive protons - II. Interacting supernova remnants

Deep GMRT radio observations and a multi-wavelength study of the region around HESS J1858+020

Microphysics of Cosmic Ray Driven Plasma Instabilities

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