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Constraining cold dark matter halo merger rates using the coagulation equations

Benson, Andrew J. (2008) Constraining cold dark matter halo merger rates using the coagulation equations. Monthly Notices of the Royal Astronomical Society, 388 (3). pp. 1361-1371. ISSN 0035-8711. doi:10.1111/j.1365-2966.2008.13491.x.

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We place additional constraints on the three parameters of the dark matter halo merger rate function recently proposed by Parkinson, Cole & Helly by utilizing Smoluchowski's coagulation equation, which must be obeyed by any binary merging process which conserves mass. We find that the constraints from Smoluchowski's equation are degenerate, limiting to a thin plane in the three-dimensional parameter space. This constraint is consistent with those obtained from fitting to N-body measures of progenitor mass functions, and provides a better match to the evolution of the overall dark matter halo mass function, particularly for the most massive haloes. We demonstrate that the proposed merger rate function does not permit an exact solution of Smoluchowski's equation and, therefore, the choice of parameters must reflect a compromise between fitting various parts of the mass function. The techniques described herein are applicable to more general merger rate functions, which may permit a more accurate solution of Smoluchowski's equation. The current merger rate solutions are most probably sufficiently accurate for the vast majority of applications.

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Benson, Andrew J.0000-0001-5501-6008
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Additional Information:© 2008 The Author. Journal compilation © 2008 RAS. Accepted 2008 May 19. Received 2008 May 7; in original form 2008 February 25. AJB acknowledges the support of the Gordon and Betty Moore Foundation. This work has benefited from conversations with numerous people. In particular, we would like to thank Shaun Cole, Steve Furlanetto, Dan Grin, Marc Kamionkowski, Hannah Parkinson, Cristiano Porciani and Tristan Smith for valuable discussions. We would like to thank the anonymous referee for suggestions which helped improve this work.
Group:TAPIR, Moore Center for Theoretical Cosmology and Physics
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Gordon and Betty Moore FoundationUNSPECIFIED
Subject Keywords:gravitation; cosmology; dark matter; large-scale structure of Universe
Issue or Number:3
Record Number:CaltechAUTHORS:BENmnras08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11754
Deposited By: Archive Administrator
Deposited On:23 Sep 2008 02:54
Last Modified:08 Nov 2021 22:02

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