2011/09/16 by Sami Dib, Dib, Sami, Laurent Piau +5
Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #astro-ph.CO #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.48550/arxiv.1109.3699
In the proceedings of the French Astronomical Society meeting SF2A 2011. 8 pages, 5 figures
arxiv created 2011/09/27 · arxiv updated 2015/03/19
We describe results from semi-analytical modelling of star formation in protocluster clumps of different metallicities. In this model, gravitationally bound cores form uniformly in the clump following a prescribed core formation efficiency per unit time. After a contraction timescale which is equal to a few times their free-fall times, the cores collapse into stars and populate the IMF. Feedback from the newly formed OB stars is taken into account in the form of stellar winds. When the ratio of the effective energy of the winds to the gravitational energy of the system reaches unity, gas is removed from the clump and core and star formation are quenched. The power of the radiation driven winds has a strong dependence on metallicity and it increases with increasing metallicity. Thus, winds from stars in the high metallicity models lead to a rapid evacuation of the gas from the protocluster clump and to a reduced star formation efficiency, as compared to their low metallicity counterparts. We derive the metallicity dependent star formation efficiency per unit time in this model as a function of the gas surface density Sigmag. This is combined with the molecular gas fraction in order to derive the dependence of the surface density of star formation SigmaSFR on Sigmag. This feedback regulated model of star formation reproduces very well the observed star formation laws in galaxies extending from low gas surface densities up to the starburst regime. Furthermore, the results show a dependence of SigmaSFR on metallicity over the entire range of gas surface densities, and can also explain part of the scatter in the observations.