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Title: Line overlap and self-shielding of molecular hydrogen in galaxies

The effect of line overlap in the Lyman and Werner bands, often ignored in galactic studies of the atomic-to-molecular transition, greatly enhances molecular hydrogen self-shielding in low metallicity environments and dominates over dust shielding for metallicities below about 10% solar. We implement that effect in cosmological hydrodynamics simulations with an empirical model, calibrated against the observational data, and provide fitting formulae for the molecular hydrogen fraction as a function of gas density on various spatial scales and in environments with varied dust abundance and interstellar radiation field. We find that line overlap, while important for detailed radiative transfer in the Lyman and Werner bands, has only a minor effect on star formation on galactic scales, which, to a much larger degree, is regulated by stellar feedback.
Authors:
 [1] ;  [2]
  1. Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)
  2. Princeton University Observatory, Princeton, NJ 08544-1001 (United States)
Publication Date:
OSTI Identifier:
22370346
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGY; DENSITY; DUSTS; ELEMENT ABUNDANCE; GALAXIES; HYDRODYNAMICS; HYDROGEN; LYMAN LINES; METALLICITY; RADIANT HEAT TRANSFER; SELF-SHIELDING; SIMULATION; STARS