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The role of cold flows in the assembly of galaxy disks

Brooks, A. M. and Governato, F. and Quinn, T. and Brook, C. B. and Wadsley, J. (2009) The role of cold flows in the assembly of galaxy disks. Astrophysical Journal, 694 (1). pp. 396-410. ISSN 0004-637X.

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We use high-resolution cosmological hydrodynamical simulations to demonstrate that cold flow gas accretion, particularly along filaments, modifies the standard picture of gas accretion and cooling onto galaxy disks. In the standard picture, all gas is initially heated to the virial temperature of the galaxy as it enters the virial radius. Low-mass galaxies are instead dominated by accretion of gas that stays well below the virial temperature, and even when a hot halo is able to develop in more massive galaxies there exist dense filaments that penetrate inside of the virial radius and deliver cold gas to the central galaxy. For galaxies up to ~L*, this cold accretion gas is responsible for the star formation (SF) in the disk at all times to the present. Even for galaxies at higher masses, cold flows dominate the growth of the disk at early times. Within this modified picture, galaxies are able to accrete a large mass of cold gas, with lower initial gas temperatures leading to shorter cooling times to reach the disk. Although SF in the disk is mitigated by supernovae feedback, the short cooling times allow for the growth of stellar disks at higher redshifts than predicted by the standard model.

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Additional Information:© 2009 American Astronomical Society. Print publication: Issue 1 (2009 March 20); received 2008 October 6; accepted for publication 2008 November 28; published 2009 March 17. We thank A. Dekel, D. Keres, J. Dalcanton, S. White, and Q. Guo, for helpful conversations during this project. A.B., F.G., and T.Q. were supported by NSF ITR grant PHY-0205413. A.B. acknowledges support from aWA Space Grant fellowship. F.G. acknowledges support from a Theodore Dunham grant, HST GO-1125, NSF grant AST-0607819, and NASA ATP NNX08AG84G. Simulations were run at TACC, SDSC, Cineca, and NAS.
Funding AgencyGrant Number
NSF ITRPHY-0205413
WA Space Grant fellowshipUNSPECIFIED
Theodore Dunham grantHST GO-1125
Subject Keywords:galaxies: evolution; galaxies: formation; methods: N-body simulations
Issue or Number:1
Record Number:CaltechAUTHORS:20090506-112640182
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14163
Deposited By: Jason Perez
Deposited On:12 May 2009 19:28
Last Modified:03 Oct 2019 00:47

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