Ellis R Owen
Hi! I am Ellis Owen, an astrophysicist and Special Postdoctoral Researcher in the Astrophysical Big Bang Laboratory at RIKEN in Japan.
My research explores how cosmic rays propagate through structured, magnetised environments, how this determines their interaction with different gas phases, and how these processes shape galaxies. I combine theoretical modelling with gamma-ray, neutrino, radio and other observations to connect the microphysics of particle transport with galaxy evolution.
Contact: ellis.owen AT riken.jp
Cosmic-ray transport in structured environments
Cosmic rays do not propagate through galaxies in a smooth or uniform medium. Magnetic fields, turbulence and gas structure can strongly alter how they scatter, escape and penetrate dense regions.
My research investigates how microscopic interactions between cosmic rays and magnetic structure give rise to macroscopic transport, including when the commonly used diffusion approximation is valid and when more complex behaviour emerges. I study these processes from molecular-cloud scales to the multiphase interstellar and circumgalactic media.
Image Credit: ESA/Herschel/SPIRE/PACS/Gould Belt Survey/D. Arzoumanian (CEA Saclay)
Stephan's Quintet, a compact group of galaxies experiencing forced interactions and successive bursts of star-formation. Composite image with JWST NIRCam-MIRI. Image credit: NASA, ESA, CSA, STScI, 2022, used in accordance with STScI/NASA content use policy.
Cosmic rays and galaxy evolution
Where cosmic rays travel determines where they deposit their energy and momentum. Their transport therefore controls how strongly they couple to cold star-forming gas, galactic winds, accreting material and the circumgalactic medium.
I study how this phase-dependent coupling influences star formation, outflows, gas recycling and the broader evolution of galaxies, with the goal of connecting cosmic-ray transport physics to physically motivated feedback models.
Multimessenger probes of cosmic-ray physics
Cosmic-ray transport cannot be observed directly, but it leaves signatures across the electromagnetic spectrum and in high-energy particles.
I use gamma rays, neutrinos, radio emission, magnetic-field measurements and ionisation diagnostics to test models of cosmic-ray propagation and interactions. These observations provide complementary ways to determine where cosmic rays travel, how efficiently they are confined and how strongly they affect their environments.
Image Credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)