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The population of Milky Way satellites in the Λ cold dark matter cosmology

Font, A. S. and Benson, A. J. and Bower, R. G. and Frenk, C. S. and Cooper, A. and DeLucia, G. and Helly, J. C. and Helmi, A. and Li, S.-Y. and McCarthy, I. G. and Navarro, J. F. and Springel, V. and Starkenburg, E. and Wang, J. and White, S. D. M. (2011) The population of Milky Way satellites in the Λ cold dark matter cosmology. Monthly Notices of the Royal Astronomical Society, 417 (2). pp. 1260-1279. ISSN 0035-8711. doi:10.1111/j.1365-2966.2011.19339.x.

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We present a model for the satellites of the Milky Way in which galaxy formation is followed using semi-analytic techniques applied to the six high-resolution N-body simulations of galactic haloes of the Aquarius project. The model, calculated using the galform code, incorporates improved treatments of the relevant physics in the Λ cold dark matter cosmogony, particularly a self-consistent calculation of reionization by ultraviolet (UV) photons emitted by the forming galaxy population, including the progenitors of the central galaxy. Along the merger tree of each halo, the model calculates gas cooling (by Compton scattering off cosmic microwave background photons, molecular hydrogen and atomic processes), gas heating (from hydrogen photoionization and supernova energy), star formation and evolution. The evolution of the intergalactic medium is followed simultaneously with that of the galaxies. Star formation in the more massive progenitor subhaloes is suppressed primarily by supernova feedback, while for smaller subhaloes, it is suppressed primarily by photoionization due to external and internal sources. The model is constrained to match a wide range of properties of the present-day galaxy population as a whole, but at high redshift it requires an escape fraction of UV photons near unity in order to completely reionize the universe by redshift z ≳ 8. In the most successful model, the local sources photoionize the pre-galactic region completely by z ≃ 10. In addition to the luminosity function of Milky Way satellites, the model matches their observed luminosity–metallicity relation, their radial distribution and the inferred values of the mass within 300 pc, which in the models increase slowly but significantly with luminosity. There is a large variation in satellite properties from halo to halo, with the luminosity function, for example, varying by a factor of ∼2 among the six simulations.

Item Type:Article
Related URLs:
URLURL TypeDescription
Benson, A. J.0000-0001-5501-6008
Springel, V.0000-0001-5976-4599
Additional Information:© 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS. Accepted 2011 June 28. Received 2011 June 17; in original form 2011 February 28. Article first published online: 12 Sep. 2011. We thank Gerry Gilmore for providing us with the dwarf satellite metallicity data in Norris et al. (2010). ASF was supported by an STFC Fellowship at the Institute for Computational Cosmology in Durham and by a Royal Society Dorothy Hodgkin fellowship at the University of Cambridge. AJB acknowledges the support of the Gordon and Betty Moore Foundation. CSF acknowledges a Royal Society Wolfson Research Merit Award and ERC Advanced Investigator grant COSMIWAY. APC acknowledges an STFC studentship. GDL acknowledges financial support from the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement n. 202781. AH acknowledges funding support from the European Research Council under ERC-StG grant GALACTICA-240271. Y-SL was supported by the Netherlands Organization for Scientific Research (NWO) STARE program 643.200.501. This work was supported in part by an STFC rolling grant to the Institute for Computational Cosmology of Durham University.
Group:Moore Center for Theoretical Cosmology and Physics
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)UNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
European Community's Seventh Framework ProgrammeFP7/2007-2013
European Research Council (ERC)202781
European Research Council (ERC)GALACTICA-240271
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)643.200.501
Subject Keywords:stars: formation galaxies: evolution galaxies: formation galaxies: ISM
Issue or Number:2
Record Number:CaltechAUTHORS:20120104-075005808
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Official Citation:Font, A. S., Benson, A. J., Bower, R. G., Frenk, C. S., Cooper, A., DeLucia, G., Helly, J. C., Helmi, A., Li, Y.-S., McCarthy, I. G., Navarro, J. F., Springel, V., Starkenburg, E., Wang, J. and White, S. D. M. (2011), The population of Milky Way satellites in the Λ cold dark matter cosmology. Monthly Notices of the Royal Astronomical Society, 417: 1260–1279. doi: 10.1111/j.1365-2966.2011.19339.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:28638
Deposited By: Ruth Sustaita
Deposited On:04 Jan 2012 18:03
Last Modified:09 Nov 2021 16:59

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