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The physics of Lyman-α escape from disc-like galaxies
- Publication Year :
- 2023
- Publisher :
- Oxford University Press (OUP), 2023.
-
Abstract
- Hydrogen emission lines can provide extensive information about star-forming galaxies in both the local and high-redshift Universe. We present a detailed Lyman continuum (LyC), Lyman-alpha (Ly{\alpha}), and Balmer line (H{\alpha} and H\b{eta}) radiative transfer study of a high-resolution isolated Milky-Way simulation using the Arepo-RT radiation hydrodynamics code with the SMUGGLE galaxy formation model. The realistic framework includes stellar feedback, non-equilibrium thermochemistry, and dust grain evolution in the interstellar medium (ISM). We extend our Cosmic Ly{\alpha} Transfer (COLT) code with photoionization equilibrium Monte Carlo radiative transfer for self-consistent end-to-end (non-)resonant line predictions. Accurate LyC reprocessing to recombination emission requires modelling pre-absorption by dust (27.5%), helium ionization (8.7%), and anisotropic escape fractions (7.9%), as these reduce the available budget for hydrogen line emission (55.9%). We investigate the role of the multiphase dusty ISM, disc geometry, gas kinematics, and star formation activity in governing the physics of emission and escape, focusing on the time variability, gas phase structure, and spatial, spectral, and viewing angle dependence of the emergent photons. Isolated disc simulations are well-suited for comprehensive observational comparisons with local H{\alpha} surveys, but would require a proper cosmological circumgalactic medium (CGM) environment as well as less dust absorption and rotational broadening to serve as analogs for high-redshift Ly{\alpha} emitting galaxies. Future applications of our framework to next-generation cosmological simulations of galaxy formation including radiation-hydrodynamics that resolve<br />Comment: 28 pages, 32 figures, MNRAS, in press
- Subjects :
- ISM: kinematics and dynamics
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
extinction
FOS: Physical sciences
Astronomy and Astrophysics
line: profiles
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics - Astrophysics of Galaxies
methods: numerical
ISM: dust
line: profile
Space and Planetary Science
radiative transfer
Astrophysics of Galaxies (astro-ph.GA)
Astrophysics::Galaxy Astrophysics
Astrophysics - Cosmology and Nongalactic Astrophysics
Subjects
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....5ff83a423c46b5f63df1884eddcf9ea0
- Full Text :
- https://doi.org/10.17863/cam.97183