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Status: Bibliographieeintrag

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Verfasst von:Mac Low, Mordecai-Mark [VerfasserIn]   i
 Burkert, Andreas [VerfasserIn]   i
 Ibáñez Mejía, Juan Camilo [VerfasserIn]   i
Titel:Fast molecular cloud destruction requires fast cloud formation
Verf.angabe:Mordecai-Mark Mac Low, Andreas Burkert, and Juan C. Ibáñez-Mejía
E-Jahr:2017
Jahr:21 September 2017
Umfang:5 S.
Fussnoten:Published 2017 September 21 ; Gesehen am 18.07.2018
Titel Quelle:Enthalten in: The astrophysical journal / 2
Ort Quelle:London : Institute of Physics Publ., 1995
Jahr Quelle:2017
Band/Heft Quelle:847(2017,1) Artikel-Nummer L10, 5 Seiten
ISSN Quelle:2041-8213
Abstract:A large fraction of the gas in the Galaxy is cold, dense, and molecular. If all this gas collapsed under the influence of gravity and formed stars in a local free-fall time, the star formation rate in the Galaxy would exceed that observed by more than an order of magnitude. Other star-forming galaxies behave similarly. Yet, observations and simulations both suggest that the molecular gas is indeed gravitationally collapsing, albeit hierarchically. Prompt stellar feedback offers a potential solution to the low observed star formation rate if it quickly disrupts star-forming clouds during gravitational collapse. However, this requires that molecular clouds must be short-lived objects, raising the question of how so much gas can be observed in the molecular phase. This can occur only if molecular clouds form as quickly as they are destroyed, maintaining a global equilibrium fraction of dense gas. We therefore examine cloud formation timescales. We first demonstrate that supernova and superbubble sweeping cannot produce dense gas at the rate required to match the cloud destruction rate. On the other hand, Toomre gravitational instability can reach the required production rate. We thus argue that, although dense, star-forming gas may last only around a single global free-fall time; the dense gas in star-forming galaxies can globally exist in a state of dynamic equilibrium between formation by gravitational instability and disruption by stellar feedback. At redshift z2, the Toomre instability timescale decreases, resulting in a prediction of higher molecular gas fractions at early times, in agreement with the observations.
DOI:doi:10.3847/2041-8213/aa8a61
URL:Bitte beachten Sie: Dies ist ein Bibliographieeintrag. Ein Volltextzugriff für Mitglieder der Universität besteht hier nur, falls für die entsprechende Zeitschrift/den entsprechenden Sammelband ein Abonnement besteht oder es sich um einen OpenAccess-Titel handelt.

Volltext ; Verlag: http://dx.doi.org/10.3847/2041-8213/aa8a61
 Volltext: http://stacks.iop.org/2041-8205/847/i=1/a=L10?key=crossref.feff2598058159dbba802b8f489a7442
 DOI: https://doi.org/10.3847/2041-8213/aa8a61
Datenträger:Online-Ressource
Sprache:eng
K10plus-PPN:1577724089
Verknüpfungen:→ Zeitschrift

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