Starbursts in isolated galaxies?

Autor(en): Christian Theis
Abstrakt: I investigated the evolution of star forming dwarf galaxies by means of a one-zone model extended for dynamical evolution. This allows for a coupling between the dynamical state of the galaxy and its internal properties like star formation activity or the thermal state of the interstellar medium (ISM). The presented work focusses on the star formation (SF) activity in isolated galaxies, especially the conditions for dynamically driven star bursts induced by stellar feedback. Two types of repetitive star bursts have been found: One set (type A) of quasi-periodic star bursts is related to the dynamical timescale of the galaxy. In that case, the star formation follows the variations in the gas density induced by decaying virial oscillations. The other set (type B) of recurrent star bursts is characterized by a long quiescence period given by the sum of the dynamical and the dissipational timescale: after a first burst, the inserted energy leads to a substantial expansion of the system, by this stopping any significant SF activity. A next burst might occur, when the gas reaches high densities again, i.e. after the gas recollapsed and the energy injected by stellar feedback is dissipated. In case of a diffuse ISM model, only type A bursts are found due to the high efficiency of radiative cooling. Bursts occur then only during an initial transitory phase. In case of a clumpy ISM model (i.e. dissipation by inelastic cloud-cloud collisions), the dissipative timescale becomes of the order of the dynamical time. This allows for both, type A and type B bursts. Whereas initial transitory bursts are quite common, type B bursts are only found in a small mass range for given feedback and dissipation parameters. Œ 2005 American Institute of Physics.
Organisation(en): Institut für Astrophysik
Seiten: 57-64
Anzahl der Seiten: 8
DOI: https://doi.org/10.1063/1.2034967
Publikationsdatum: 2005
ÖFOS 2012: 103003 Astronomie
Link zum Portal: https://ucrisportal.univie.ac.at/de/publications/927b9645-611d-4f61-bc79-655c385bbbc5

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