skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: RUNAWAY STARS AND THE ESCAPE OF IONIZING RADIATION FROM HIGH-REDSHIFT GALAXIES

Abstract

Approximately 30% of all massive stars in the Galaxy are runaways with velocities exceeding 30 km s{sup -1}. Their high speeds allow them to travel {approx}0.1-1 kpc away from their birthplace before they explode at the end of their several Myr lifetimes. At high redshift, when galaxies were much smaller than in the local universe, runaways could venture far from the dense inner regions of their host galaxies. From these large radii, and therefore low column densities, much of their ionizing radiation is able to escape into the intergalactic medium. Runaways may therefore significantly enhance the overall escape fraction of ionizing radiation, f{sub esc}, from small galaxies at high redshift. We present simple models of the high-redshift runaway population and its impact on f{sub esc} as a function of halo mass, size, and redshift. We find that the inclusion of runaways enhances f{sub esc} by factors of Almost-Equal-To 1.1-8, depending on halo mass, galaxy geometry, and the mechanism of runaway production, implying that runaways may contribute 50%-90% of the total ionizing radiation escaping from high-redshift galaxies. Runaways may therefore play an important role in reionizing the universe.

Authors:
;  [1]
  1. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
Publication Date:
OSTI Identifier:
22039068
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 755; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; DENSITY; GALAXIES; IONIZING RADIATIONS; LIFETIME; RED SHIFT; STARS; UNIVERSE; VELOCITY

Citation Formats

Conroy, Charlie, and Kratter, Kaitlin M. RUNAWAY STARS AND THE ESCAPE OF IONIZING RADIATION FROM HIGH-REDSHIFT GALAXIES. United States: N. p., 2012. Web. doi:10.1088/0004-637X/755/2/123.
Conroy, Charlie, & Kratter, Kaitlin M. RUNAWAY STARS AND THE ESCAPE OF IONIZING RADIATION FROM HIGH-REDSHIFT GALAXIES. United States. https://doi.org/10.1088/0004-637X/755/2/123
Conroy, Charlie, and Kratter, Kaitlin M. 2012. "RUNAWAY STARS AND THE ESCAPE OF IONIZING RADIATION FROM HIGH-REDSHIFT GALAXIES". United States. https://doi.org/10.1088/0004-637X/755/2/123.
@article{osti_22039068,
title = {RUNAWAY STARS AND THE ESCAPE OF IONIZING RADIATION FROM HIGH-REDSHIFT GALAXIES},
author = {Conroy, Charlie and Kratter, Kaitlin M},
abstractNote = {Approximately 30% of all massive stars in the Galaxy are runaways with velocities exceeding 30 km s{sup -1}. Their high speeds allow them to travel {approx}0.1-1 kpc away from their birthplace before they explode at the end of their several Myr lifetimes. At high redshift, when galaxies were much smaller than in the local universe, runaways could venture far from the dense inner regions of their host galaxies. From these large radii, and therefore low column densities, much of their ionizing radiation is able to escape into the intergalactic medium. Runaways may therefore significantly enhance the overall escape fraction of ionizing radiation, f{sub esc}, from small galaxies at high redshift. We present simple models of the high-redshift runaway population and its impact on f{sub esc} as a function of halo mass, size, and redshift. We find that the inclusion of runaways enhances f{sub esc} by factors of Almost-Equal-To 1.1-8, depending on halo mass, galaxy geometry, and the mechanism of runaway production, implying that runaways may contribute 50%-90% of the total ionizing radiation escaping from high-redshift galaxies. Runaways may therefore play an important role in reionizing the universe.},
doi = {10.1088/0004-637X/755/2/123},
url = {https://www.osti.gov/biblio/22039068}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 755,
place = {United States},
year = {Mon Aug 20 00:00:00 EDT 2012},
month = {Mon Aug 20 00:00:00 EDT 2012}
}