Temperature fluctuations in HII regions: ionization by Cosmic Rays as a key mechanism

Abstract

We present a detailed model capable of explaining quantitatively the temperature fluctuations observed in luminous, large HII regions. The model is based on two assumptions which we justify on the basis of observations: that the major fraction of the hydrogen in the clouds that form the HII regions is not photoionized and is essentially HI, this HII is lightly ionized by fluxes of low energy cosmic rays (CR) produced by processes originating in the hot stars which illuminate the regions.

arXiv comment5 pages, 1 figure. Accepted for publication by A&A letters

References in corpus (7)

• The Chemical Composition of the Small Magellanic Cloud H II Region NGC 346 and the Primordial Helium Abundance
• The Chemical Composition of the 30 Doradus Nebula Derived from VLT Echelle Spectrophotometry
• Optical Recombination Lines of Heavy-elements in Giant Extragalactic HII Regions
• The internal dynamical equilibrium of HII regions: a statistical study
• Propagation of ionizing radiation in HII regions: the effects of optically thick density fluctuations
• Gamma Ray Lines from the Orion Complex
• Temperature Fluctuations and Abundances in HII Galaxies

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• Interactions between Ultra-High-Energy Particles and Protogalactic Environments
• Temperature Structure and Metallicity in H II Regions
• Electron Energy Distributions in HII Regions and Planetary Nebulae: kappa-Distributions Do Not Apply
• Electron temperature fluctuations in NGC 346
• Constraints on the densities and temperature of Seyfert 2 NLR
• Hadronic Interactions of Energetic Charged Particles in Protogalactic Outflow Environments and Implications for the Early Evolution of Galaxies
• Temperature fluctuations in H II regions: t2 for the two-phase model
• Electron Energy Distributions in the Extended Gas Nebulae associated with High-z AGN: Maxwell-Boltzmann vs. kappa distributions
• Astrophysics in 2005