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Title: ASSESSING RADIATION PRESSURE AS A FEEDBACK MECHANISM IN STAR-FORMING GALAXIES

Abstract

Radiation pressure from the absorption and scattering of starlight by dust grains may be an important feedback mechanism in regulating star-forming galaxies. We compile data from the literature on star clusters, star-forming subregions, normal star-forming galaxies, and starbursts to assess the importance of radiation pressure on dust as a feedback mechanism, by comparing the luminosity and flux of these systems to their dust Eddington limit. This exercise motivates a novel interpretation of the Schmidt law, the L{sub IR}-L'{sub CO} correlation, and the L{sub IR}-L'{sub HCN} correlation. In particular, the linear L{sub IR}-L'{sub HCN} correlation is a natural prediction of radiation pressure regulated star formation. Overall, we find that the Eddington limit sets a hard upper bound to the luminosity of any star-forming region. Importantly, however, many normal star-forming galaxies have luminosities significantly below the Eddington limit. We explore several explanations for this discrepancy, especially the role of 'intermittency' in normal spirals-the tendency for only a small number of subregions within a galaxy to be actively forming stars at any moment because of the time dependence of the feedback process and the luminosity evolution of the stellar population. If radiation pressure regulates star formation in dense gas, then the gas depletionmore » timescale is 6 Myr, in good agreement with observations of the densest starbursts. Finally, we highlight the importance of observational uncertainties, namely, the dust-to-gas ratio and the CO-to-H{sub 2} and HCN-to-H{sub 2} conversion factors, that must be understood before a definitive assessment of radiation pressure as a feedback mechanism in star-forming galaxies.« less

Authors:
Publication Date:
OSTI Identifier:
21567551
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 727; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/727/2/97; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON MONOXIDE; CONVERSION; DUSTS; FEEDBACK; GALACTIC EVOLUTION; GALAXIES; HYDROCYANIC ACID; HYDROGEN; LUMINOSITY; RADIATION PRESSURE; STAR CLUSTERS; STAR EVOLUTION; STARS; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; ELEMENTS; EVOLUTION; HYDROGEN COMPOUNDS; INORGANIC ACIDS; INORGANIC COMPOUNDS; NONMETALS; OPTICAL PROPERTIES; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES

Citation Formats

Andrews, Brett H, and Thompson, Todd A., E-mail: andrews@astronomy.ohio-state.edu. ASSESSING RADIATION PRESSURE AS A FEEDBACK MECHANISM IN STAR-FORMING GALAXIES. United States: N. p., 2011. Web. doi:10.1088/0004-637X/727/2/97.
Andrews, Brett H, & Thompson, Todd A., E-mail: andrews@astronomy.ohio-state.edu. ASSESSING RADIATION PRESSURE AS A FEEDBACK MECHANISM IN STAR-FORMING GALAXIES. United States. https://doi.org/10.1088/0004-637X/727/2/97
Andrews, Brett H, and Thompson, Todd A., E-mail: andrews@astronomy.ohio-state.edu. 2011. "ASSESSING RADIATION PRESSURE AS A FEEDBACK MECHANISM IN STAR-FORMING GALAXIES". United States. https://doi.org/10.1088/0004-637X/727/2/97.
@article{osti_21567551,
title = {ASSESSING RADIATION PRESSURE AS A FEEDBACK MECHANISM IN STAR-FORMING GALAXIES},
author = {Andrews, Brett H and Thompson, Todd A., E-mail: andrews@astronomy.ohio-state.edu},
abstractNote = {Radiation pressure from the absorption and scattering of starlight by dust grains may be an important feedback mechanism in regulating star-forming galaxies. We compile data from the literature on star clusters, star-forming subregions, normal star-forming galaxies, and starbursts to assess the importance of radiation pressure on dust as a feedback mechanism, by comparing the luminosity and flux of these systems to their dust Eddington limit. This exercise motivates a novel interpretation of the Schmidt law, the L{sub IR}-L'{sub CO} correlation, and the L{sub IR}-L'{sub HCN} correlation. In particular, the linear L{sub IR}-L'{sub HCN} correlation is a natural prediction of radiation pressure regulated star formation. Overall, we find that the Eddington limit sets a hard upper bound to the luminosity of any star-forming region. Importantly, however, many normal star-forming galaxies have luminosities significantly below the Eddington limit. We explore several explanations for this discrepancy, especially the role of 'intermittency' in normal spirals-the tendency for only a small number of subregions within a galaxy to be actively forming stars at any moment because of the time dependence of the feedback process and the luminosity evolution of the stellar population. If radiation pressure regulates star formation in dense gas, then the gas depletion timescale is 6 Myr, in good agreement with observations of the densest starbursts. Finally, we highlight the importance of observational uncertainties, namely, the dust-to-gas ratio and the CO-to-H{sub 2} and HCN-to-H{sub 2} conversion factors, that must be understood before a definitive assessment of radiation pressure as a feedback mechanism in star-forming galaxies.},
doi = {10.1088/0004-637X/727/2/97},
url = {https://www.osti.gov/biblio/21567551}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 727,
place = {United States},
year = {Tue Feb 01 00:00:00 EST 2011},
month = {Tue Feb 01 00:00:00 EST 2011}
}