Cosmic Ray Processes in Galactic Ecosystems

Owen, Ellis R.; Wu, Kinwah; Inoue, Yoshiyuki; Yang, H.-Y. Karen; Mitchell, Alison

doi:10.3390/galaxies11040086

Cited by 5 publications

(1 citation statement)

References 710 publications

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“…It is also strongly believed that extremely high-energy cosmic rays may emerge from active galactic nuclei (AGN) [11,12] and gamma ray bursts [13,14]. In this context, it is worth noting that termination shocks of galactic outflows and star-forming regions are also considered as possible sources for ultra-high-energy particles [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Radio Pulsars Resonantly Accelerating Electrons

Osmanov,

Mahajan

2023

Astronomy

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Based on the recently demonstrated resonant wave–wave process, it is shown that electrons can be accelerated to ultra-relativistic energies in the magnetospheres of radio pulsars. The energization occurs via the resonant interaction of the electron wave (described by the Klein–Gordon (KG) equation) moving in unison with an intense electromagnetic (EM) wave; the KG wave/particle continuously draws energy from EM. In a brief recapitulation of the general theory, the high-energy (resonantly enhanced) electron states are investigated by solving the KG equation, minimally coupled to the EM field. The restricted class of solutions that propagate in phase with EM radiation (functions only of ζ=ωt−kz) are explored to serve as a possible basis for the proposed electron energization in the radio pulsars. We show that the wave–wave resonant energization mechanism could be operative in a broad class of radio pulsars with periods ranging from milliseconds to normal values (∼1 s); this could drive the magnetospheric electrons to acquire energies from 100 s of TeVs (millisecond pulsars) to 10 ZeVs (normal pulsars).

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Section: Introductionmentioning

confidence: 99%

Radio Pulsars Resonantly Accelerating Electrons

Osmanov,

Mahajan

2023

Astronomy

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A fluid approach to cosmic-ray modified shocks

Ramzan,

Qazi,

Salarzai

et al. 2024

Advances in Space Research

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Synchrotron emission on FIRE: equipartition estimators of magnetic fields in simulated galaxies with spectrally resolved cosmic rays

Ponnada,

Panopoulou,

Butsky

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Synchrotron emission is one of few observable tracers of galactic magnetic fields (B) and cosmic rays (CRs). Much of our understanding of B in galaxies comes from utilizing synchrotron observations in conjunction with several simplifying assumptions of equipartition models, however it remains unclear how well these assumptions hold, and what B these estimates physically represent. Using FIRE simulations which self consistently evolve CR proton, electron, and positron spectra from MeV to TeV energies, we present the first synthetic synchrotron emission predictions from simulated L* galaxies with ”live” spectrally-resolved CR-MHD. We find that synchrotron emission can be dominated by relatively cool and dense gas, resulting in equipartition estimates of B with fiducial assumptions underestimating the ”true” B in the gas that contributes the most emission by factors of 2-3 due to small volume filling factors. Motivated by our results, we present an analytic framework that expands upon equipartition models for estimating B in a multi-phase medium. Comparing our spectrally-resolved synchrotron predictions to simpler spectral assumptions used in galaxy simulations with CRs, we find that spectral evolution can be crucial for accurate synchrotron calculations towards galactic centers, where loss terms are large.

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Cosmic Ray Processes in Galactic Ecosystems

Cited by 5 publications

References 710 publications

Radio Pulsars Resonantly Accelerating Electrons

Radio Pulsars Resonantly Accelerating Electrons

A fluid approach to cosmic-ray modified shocks

Synchrotron emission on FIRE: equipartition estimators of magnetic fields in simulated galaxies with spectrally resolved cosmic rays

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