The Role of Pressure in GMC Formation II: The H2-Pressure Relation
Leo Blitz,Erik Rosolowsky +1 more
TLDR
In this article, the authors show that the ratio of molecular to atomic gas in galaxies is determined by hydrostatic pressure and that the relation between the two is nearly linear, and propose a modified star formation prescription based on pressure determining the degree to which the ISM is molecular.Abstract:
We show that the ratio of molecular to atomic gas in galaxies is determined by hydrostatic pressure and that the relation between the two is nearly linear. The pressure relation is shown to be good over 3 orders of magnitude for 14 galaxies, including dwarfs, H I-rich, and H2-rich galaxies, as well as the Milky Way. The sample spans a factor of 5 in mean metallicity. The rms scatter of individual points of the relation is only about a factor of 2 for all the galaxies, although some show much more scatter than others. Using these results, we propose a modified star formation prescription based on pressure determining the degree to which the ISM is molecular. The formulation is different in high- and low-pressure regimes, defined by whether the gas is primarily atomic or primarily molecular. This formulation can be implemented in simulations and provides a more appropriate treatment of the outer regions of spiral galaxies and molecule-poor systems, such as dwarf irregulars and damped Lyα systems.read more
Citations
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Journal ArticleDOI
Star Formation in the Milky Way and Nearby Galaxies
TL;DR: In this paper, the authors review progress over the past decade in observations of large-scale star formation, with a focus on the interface between extragalactic and Galactic studies.
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Theory of Star Formation
TL;DR: In this paper, an overall theoretical framework and the observations that motivate it are outlined, outlining the key dynamical processes involved in star formation, including turbulence, magnetic fields, and self-gravity.
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The Star Formation Efficiency in Nearby Galaxies: Measuring Where Gas Forms Stars Effectively
Adam Leroy,Fabian Walter,Elias Brinks,Frank Bigiel,W. J. G. de Blok,W. J. G. de Blok,Barry F. Madore,Michele D. Thornley +7 more
TL;DR: In this paper, the star formation efficiency (SFE) per unit of gas in 23 nearby galaxies and compare it with expectations from proposed star formation laws and thresholds was measured, and the authors interpreted this decline as a strong dependence of giant molecular cloud (GMC) formation on environment.
Journal ArticleDOI
The Spitzer c2d legacy results: star-formation rates and efficiencies; evolution and lifetimes
Neal J. Evans,Michael M. Dunham,Jes K. Jørgensen,Melissa L. Enoch,Melissa L. Enoch,Bruno Merín,Bruno Merín,Ewine F. van Dishoeck,Juan M. Alcalá,Philip C. Myers,Karl R. Stapelfeldt,Tracy L. Huard,Tracy L. Huard,Lori Allen,Paul M. Harvey,Tim A. van Kempen,Geoffrey A. Blake,David W. Koerner,Lee G. Mundy,Deborah L. Padgett,Anneila I. Sargent +20 more
TL;DR: In this article, the authors combined information drawn from studies of individual clouds into a combined and updated statistical analysis of star-formation rates and efficiencies, numbers and lifetimes for spectral energy distribution (SED) classes, and clustering properties.
Journal ArticleDOI
High molecular gas fractions in normal massive star-forming galaxies in the young Universe
Linda J. Tacconi,Reinhard Genzel,R. Neri,Pierre Cox,Michael C. Cooper,K. Shapiro,Alberto D. Bolatto,Nicolas Bouché,Frédéric Bournaud,Andreas Burkert,Francoise Combes,Julia M. Comerford,Michael Davis,N. M. Förster Schreiber,Santiago García-Burillo,Javier Graciá-Carpio,Dieter Lutz,T. Naab,Alain Omont,Alice E. Shapley,Amiel Sternberg,Benjamin J. Weiner +21 more
TL;DR: A survey of molecular gas in samples of typical massive-star-forming galaxies at mean redshifts of about 1.2 and 2.3 reveals that distant star forming galaxies were indeed gas rich, and that the star formation efficiency is not strongly dependent on cosmic epoch.
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