The Interstellar Medium in Dwarf Irregular Galaxies

Fuente: arXiv
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Autori principali: Hunter, Deidre A., Elmegreen, Bruce G., Madden, Suzanne C.
Natura: Preprint
Pubblicazione: 2024
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author Hunter, Deidre A.
Elmegreen, Bruce G.
Madden, Suzanne C.
author_facet Hunter, Deidre A.
Elmegreen, Bruce G.
Madden, Suzanne C.
contents Dwarf irregulars (dIrrs) are among the most common type of galaxy in the Universe. They typically have gas-rich, low surface-brightness, metal-poor, and relatively-thick disks. Here we summarize the current state of our knowledge of the interstellar medium (ISM), including atomic, molecular and ionized gas, along with their dust properties and metals. We also discuss star formation feedback, gas accretion, and mergers with other dwarfs that connect the ISM to the circumgalactic and intergalactic media. We highlight one of the most persistent mysteries: the nature of pervasive gas that is yet undetected as either molecular or cold hydrogen, the ``dark gas''. Here are a few highlights: 1. Significant quantities of HI are in far-outer gas disks. 2. Cold HI in dIrrs would be molecular in the Milky Way, making the chemical properties of star-forming clouds significantly different. 3. Stellar feedback has a much larger impact in dIrrs than in spiral galaxies. 4. The escape fraction of ionizing photons is significant, making dIrrs a plausible source for reionization in the early Universe. 5. Observations suggest a significantly higher abundance of hydrogen (H$_2$ or cold HI) associated with CO in star-forming regions than that traced by the CO alone.
format Preprint
id arxiv_https___arxiv_org_abs_2402_17004
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Interstellar Medium in Dwarf Irregular Galaxies
Hunter, Deidre A.
Elmegreen, Bruce G.
Madden, Suzanne C.
Astrophysics of Galaxies
Dwarf irregulars (dIrrs) are among the most common type of galaxy in the Universe. They typically have gas-rich, low surface-brightness, metal-poor, and relatively-thick disks. Here we summarize the current state of our knowledge of the interstellar medium (ISM), including atomic, molecular and ionized gas, along with their dust properties and metals. We also discuss star formation feedback, gas accretion, and mergers with other dwarfs that connect the ISM to the circumgalactic and intergalactic media. We highlight one of the most persistent mysteries: the nature of pervasive gas that is yet undetected as either molecular or cold hydrogen, the ``dark gas''. Here are a few highlights: 1. Significant quantities of HI are in far-outer gas disks. 2. Cold HI in dIrrs would be molecular in the Milky Way, making the chemical properties of star-forming clouds significantly different. 3. Stellar feedback has a much larger impact in dIrrs than in spiral galaxies. 4. The escape fraction of ionizing photons is significant, making dIrrs a plausible source for reionization in the early Universe. 5. Observations suggest a significantly higher abundance of hydrogen (H$_2$ or cold HI) associated with CO in star-forming regions than that traced by the CO alone.
title The Interstellar Medium in Dwarf Irregular Galaxies
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2402.17004