Do Cosmic Rays Heat the Early Intergalactic Medium?

Abstract

Cosmic rays (CRs) govern the energetics of present-day galaxies and might have also played a pivotal role during the Epoch of Reionization. In particular, energy deposition by low-energy ($E\lesssim 10$ MeV) CRs accelerated by the first supernovae, might have heated and ionized the neutral intergalactic medium (IGM) well before ($z\approx 20$) it was reionized, significantly adding to the similar effect by X-rays or dark matter annihilations. Using a simple, but physically motivated reionization model, and a thorough implementation of CR energy losses, we show that CRs contribute negligibly to IGM ionization, but heat it substantially, raising its temperature by $\Delta T=10-200$ K by $z=10$, depending on the CR injection spectrum. Whether this IGM pre-heating is uniform or clustered around the first galaxies depends on CR diffusion, in turn governed by the efficiency of self-confinement due to plasma streaming instabilities that we discuss in detail. This aspect is crucial to interpret future HI 21 cm observations which can be used to gain unique information on the strength and structure of early intergalactic magnetic fields, and the efficiency of CR acceleration by the first supernovae.

10 pages, 7 figures

References in corpus (14)

• Cosmic Star Formation History
• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Fragmentation of star-forming clouds enriched with the first dust
• 21 cm fluctuations from inhomogeneous X-ray heating before reionization
• Population III stars: hidden or disappeared ?
• Evolution of the Intergalactic Opacity: Implications for the Ionizing Background, Cosmic Star Formation, and Quasar Activity
• Self-regulated reionization
• Gamma rays from molecular clouds
• Simulating cosmic metal enrichment by the first galaxies
• Cosmic ray physics in calculations of cosmological structure formation
• Population III Generated Cosmic Rays and the Production of Li6
• The Linear Instability of Dilute Ultrarelativistic $e^{\pm }$ Pair Beams
• Cosmic rays and the primordial gas
• Cosmic Ray production of Beryllium and Boron at high redshift

Cited by in corpus (25)

• The Epoch of IGM heating by early sources of X-rays
• Test particle simulations of cosmic rays
• Large scale simulations of H and He reionization and heating driven by stars and more energetic sources
• Dark Matter microphysics and 21 cm observations
• A hydrodynamical study of outflows in starburst galaxies with different driving mechanisms
• SPICE: the connection between cosmic reionisation and stellar feedback in the first galaxies
• Studying Cosmic Dawn using redshifted HI 21-cm signal: A brief review
• Starburst and post-starburst high-redshift protogalaxies: The feedback impact of high energy cosmic rays
• Green Peas in X-rays
• 21 cm Forest Constraints on Primordial Black Holes
• The seeds of supermassive black holes and the role of local radiation and metal spreading
• Interactions between Ultra-High-Energy Particles and Protogalactic Environments
• Signatures of Cosmic Ray Heating in 21-cm Observables
• Microquasars as heating sources of the intergalactic medium during reionisation of the Universe
• Origin and Impacts of the First Cosmic Rays
• Highly collimated microquasar jets as efficient cosmic-ray sources
• Hadronic Interactions of Energetic Charged Particles in Protogalactic Outflow Environments and Implications for the Early Evolution of Galaxies
• The EDGES measurement disfavors an excess radio background during the cosmic dawn
• Impact of ultraluminous X-ray sources on photoabsorption in the first galaxies
• Impact of cosmic rays on the global 21-cm signal during cosmic dawn
• Resistive Heating Induced by Streaming Cosmic Rays Around a Galaxy in the Early Universe
• Thermal Regulation and the Star-Forming Main Sequence
• Biermann Battery Powered by Resistive Heating Induced by Cosmic Ray Streaming
• Narrowing the discovery space of the cosmological 21-cm signal using multi-wavelength constraints
• A universal 21 cm signature of growing massive black holes in the early Universe