Cosmic Rays in Superbubbles

Tolksdorf, T.; Grenier, I. A.; Joubaud, T.; Schlickeiser, R.

doi:10.3847/1538-4357/ab24c6

Cited by 11 publications

(17 citation statements)

References 25 publications

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“…Galactic CR may not penetrate deep into the superbubble if there is strong turbulence inside it (Tolksdorf et al 2019). Conversely, for an inefficient accelerator as the Orion-Eridanus superbubble seems to be, CR can pass through the hot plasma without significant changes.…”

Section: The Cosmic-ray Flux In the Superbubblementioning

confidence: 99%

“…The downstream medium may also be rich in supra-thermal particles due to the series of past supernova remnants in the superbubble and they can get reaccelerated. Tolksdorf et al (2019) have analytically studied stochastic re-acceleration in the turbulent interior of a spherical superbubble, including spatial and momentum diffusion as well as pion losses. The acceleration potential is captured by the ratio of the acceleration time scale, τ A ∼ 9D(p)/v 2 A , over the diffusive escape timescale, τ D ∼ R 2 S B /D(p), with R S B the superbubble radius, v A the Alfven velocity in the interior plasma, and D(p) the spatial diffusion coefficient estimated in Sect.…”

Section: Cosmic-ray Re-accelerationmentioning

confidence: 99%

“…12. Theoretical steady-state proton distribution, integrated between 10 GeV and 10 TeV, for Galactic cosmic rays injected at the edge of the turbulent superbubble (according to Tolksdorf et al 2019). The different curves correspond to different values of the efficiency parameter ξ.…”

Section: Cosmic-ray Re-accelerationmentioning

confidence: 99%

“…Particle interactions with magnetohydrodynamic (MHD) waves in the turbulent plasma can re-accelerate the CR despite pion losses along their path. For efficient superbubbles, with acceleration time scales much shorter than the diffusive escape time scale from the bubble, the resulting hadronic γ-ray emission can exhibit power-law differential spectra as hard as E −0.3 γ in the 1-100 GeV energy band (Tolksdorf et al 2019). The re-accelerated CR should accumulate at the periphery of the superbubble as the enhanced turbulence prevents their penetration deep into the interior (Tolksdorf et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…For efficient superbubbles, with acceleration time scales much shorter than the diffusive escape time scale from the bubble, the resulting hadronic γ-ray emission can exhibit power-law differential spectra as hard as E −0.3 γ in the 1-100 GeV energy band (Tolksdorf et al 2019). The re-accelerated CR should accumulate at the periphery of the superbubble as the enhanced turbulence prevents their penetration deep into the interior (Tolksdorf et al 2019). Conversely, CR that are produced internally can remain confined in the superbubble medium for typically 300 kyr for 100 GeV particles in a 25-50 pc superbubble if the diffusion lengths are 100 times shorter than in the Article number, page 1 of 20 arXiv:2001.10139v1 [astro-ph.HE] 28 Jan 2020 the key H α features towards Orion.…”

Section: Introductionmentioning

confidence: 99%

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The cosmic-ray content of the Orion-Eridanus superbubble

Joubaud

Grenier

Casandjian

et al. 2020

A&A

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Aims. The nearby Orion-Eridanus superbubble, which was blown by multiple supernovae several million years ago, has likely produced cosmic rays. Its turbulent medium is still energised by massive stellar winds and it can impact cosmic-ray transport locally. The γ radiation produced in interactions between cosmic rays and interstellar gas can be used to compare the cosmic-ray spectrum in the superbubble and in other regions near the Sun. It can reveal spectral changes induced in GeV to TeV cosmic rays by the past and present stellar activity in the superbubble. Methods. We used ten years of data from the Fermi Large Area Telescope (LAT) in the 0.25-63 GeV energy range to study the closer (Eridanus) end of the superbubble at low Galactic latitudes. We modelled the spatial and spectral distributions of the γ rays produced in the different gas phases (atomic, molecular, dark, and ionised) of the clouds found in this direction. The model included other non-gaseous components to match the data. Results. We found that the γ-ray emissivity spectrum of the gas along the outer rim and in a shell inside the superbubble is consistent with the average spectrum measured in the solar neighbourhood. It is also consistent with the cosmic-ray spectrum directly measured in the Solar System. This homogeneity calls for a detailed assessment of the recent supernova rate and current census of massive stellar winds in the superbubble in order to estimate the epoch and rate of cosmic-ray production and to constrain the transport conditions that can lead to such homogeneity and little re-acceleration. We also found significant evidence that a diffuse atomic cloud lying outside the superbubble, at a height of 200-250 pc below the Galactic plane, is pervaded by a 34% lower cosmic-ray flux, but with the same particle energy distribution as the local one. Super-GeV cosmic rays should freely cross such a light and diffuse cirrus cloud without significant loss or spectral distorsion. We tentatively propose that the cosmic-ray loss relates to the orientation of the magnetic field lines threading the cirrus, which point towards the halo according to the dust polarisation data from Planck. Finally, we gathered the present emissivity measurements with previous estimates obtained around the Sun to show how the local cosmic-ray flux decreases with Galactic height and to compare this trend with model predictions.

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Section: The Cosmic-ray Flux In the Superbubblementioning

confidence: 99%

Section: Cosmic-ray Re-accelerationmentioning

confidence: 99%

Section: Cosmic-ray Re-accelerationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The cosmic-ray content of the Orion-Eridanus superbubble

Joubaud

Grenier

Casandjian

et al. 2020

A&A

Self Cite

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High-Energy Particles and Radiation in Star-Forming Regions

et al. 2020

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Non-thermal particles and high-energy radiation can play a role in the dynamical processes in star-forming regions and provide an important piece of the multiwavelength observational picture of their structure and components. Powerful stellar winds and supernovae in compact clusters of massive stars and OB associations are known to be favourable sites of high-energy particle acceleration and sources of non-thermal radiation and neutrinos. Namely, young massive stellar clusters are likely sources of the PeV (petaelectronvolt) regime cosmic rays (CRs). They can also be responsible for the cosmic ray composition, e.g., 22 Ne/ 20 Ne anomalous isotopic ratio in CRs. Efficient particle acceleration can be accompanied by super-adiabatic amplification of the fluctuating magnetic fields in the systems converting a part of kinetic power of the winds and supernovae into the magnetic energy through the CR-driven instabilities. The escape and CR propagation in the vicinity of the sources are affected by the non-linear CR feedback. These effects are expected to be important in starburst galaxies, which produce high-energy neutrinos and gamma-rays. We give a brief review of the theoreti-A. M. Bykov

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Modeling of GeV-TeV gamma-ray emission of Cygnus Cocoon

Bykov

Kalyashova

2022

Advances in Space Research

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Cosmic Rays in Superbubbles

Cited by 11 publications

References 25 publications

The cosmic-ray content of the Orion-Eridanus superbubble

The cosmic-ray content of the Orion-Eridanus superbubble

High-Energy Particles and Radiation in Star-Forming Regions

Modeling of GeV-TeV gamma-ray emission of Cygnus Cocoon

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