Hadronic interactions of energetic charged particles in protogalactic outflow environments and implications for the early evolution of galaxies
Abstract
We investigate the interactions of energetic hadronic particles with the media in outflows from star-forming protogalaxies. These particles undergo pion-producing interactions which can drive a heating effect in the outflow, while those advected by the outflow also transport energy beyond the galaxy, heating the circumgalactic medium. We investigate how this process evolves over the length of the outflow and calculate the corresponding heating rates in advection-dominated and diffusion-dominated cosmic ray transport regimes. In a purely diffusive transport scenario, we find the peak heating rate reaches 10^{-26} erg cm^{-3} s^{-1} at the base of the outflow where the wind is driven by core-collapse supernovae at an event rate of 0.1 yr-1, but does not extend beyond 2 kpc. In the advection limit, the peak heating rate is reduced to 10^{-28} erg cm^{-3} s^{-1}, but its extent can reach to tens of kpc. Around 10 per cent of the cosmic rays injected into the system can escape by advection with the outflow wind, while the remaining cosmic rays deliver an important interstellar heating effect. We apply our cosmic ray heating model to the recent observation of the high-redshift galaxy MACS1149-JD1 and show that it could account for the quenching of a previous starburst inferred from spectroscopic observations. Re-ignition of later star-formation may be caused by the presence of filamentary circumgalactic inflows which are reinstated after cosmic ray heating has subsided.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2019
- DOI:
- 10.1093/mnras/stz060
- arXiv:
- arXiv:1901.01411
- Bibcode:
- 2019MNRAS.484.1645O
- Keywords:
-
- stars: winds;
- outflows;
- cosmic rays;
- galaxies: clusters: general;
- galaxies: evolution;
- galaxies: high-redshift;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 29 pages, 16 figures, accepted for publication in MNRAS. v2: updated to match published version (reference added, minor typos corrected)