DLA kinematics and outflows from starburst galaxies

Abstract

We present results from a numerical study of the multiphase interstellar medium in sub-Lyman-break galaxy protogalactic clumps. Such clumps are abundant at z=3 and are thought to be a major contributor to damped Ly-alpha absorption. We model the formation of winds from these clumps and show that during star formation episodes they feature outflows with neutral gas velocity widths up to several hundred km/s. Such outflows are consistent with the observed high-velocity dispersion in DLAs. In our models thermal energy feedback from winds and supernovae results in efficient outflows only when cold (~ 300 K), dense (> 100 msun/pc^3) clouds are resolved at grid resolution of 12 pc. At lower 24 pc resolution the first signs of the multiphase medium are spotted; however, at this low resolution thermal injection of feedback energy cannot yet create hot expanding bubbles around star-forming regions -- instead feedback tends to erase high-density peaks and suppress star formation. At 12 pc resolution feedback compresses cold clouds, often without disrupting the ongoing star formation; at the same time a larger fraction of feedback energy is channeled into low-density bubbles and winds. These winds often entrain compact neutral clumps which produce multi-component metal absorption lines.

ApJ submitted, 10 figures, printing in colour recommended, comments welcome

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Cited by in corpus (6)

• Absorption line systems in simulated galaxies fed by cold streams
• Damped Lyman-alpha absorbers as a probe of stellar feedback
• Reproducing the Kinematics of Damped Lyman-alpha Systems
• Star Formation from DLA Gas in the Outskirts of Lyman Break Galaxies at z~3
• Effect of radiative transfer on damped Lyman-alpha and Lyman limit systems in cosmological SPH simulations
• Damped Lyman-$\alpha$ absorbers and atomic hydrogen in galaxies: the view of the GAEA model