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Paper: Radio emission from small galaxies
Volume: 18, The Interpretation of Modern Synthesis Observations of Spiral Galaxies
Page: 191
Authors: Gallagher, John S., III
Abstract: The correlation between FIR emission and radio luminosity is studied for small irregular star-forming disk galaxies that have known star-formation rates (SFRs) and available multiwavelength photometry. The characteristics of SFR measurements and nonthermal radio emission from these galaxies is described, and the power in cosmic rays (PCR) is not expected to contribute to nonthermal radiation. A model is proposed for NGC 1569 that can explain the enhanced escape of high-energy cosmic rays, and the implications of the analysis are discussed for the magnetic fields in irregular galaxies. FIR flux is shown to be approximately equal to the product of UV stellar luminosity and mean absorption optical depth. It is postulated that SFR depends on gas density and the state of galactic ISM, and the observed anticorrelation between dense gas and nonthermal radio in spirals is related to the magnetic field, ISM cloud structure, and diffusion losses. The data are shown to be relevant to the interaction between star formation processes and global galactic environments.
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