Tinker, Jeremy L. and Robertson, Brant E. and Kravtsov, Andrey V. and Klypin, Anatoly and Warren, Michael S. and Yepes, Gustavo and Gottlöber, Stefan (2010) The large-scale bias of dark matter halos: numerical calibration and model tests. Astrophysical Journal, 724 (2). pp. 878-886. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20110110-114811314
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We measure the clustering of dark matter halos in a large set of collisionless cosmological simulations of the flat ΛCDM cosmology. Halos are identified using the spherical overdensity algorithm, which finds the mass around isolated peaks in the density field such that the mean density is Δ times the background. We calibrate fitting functions for the large-scale bias that are adaptable to any value of Δ we examine. We find a ~6% scatter about our best-fit bias relation. Our fitting functions couple to the halo mass functions of Tinker et al. such that the bias of all dark matter is normalized to unity. We demonstrate that the bias of massive, rare halos is higher than that predicted in the modified ellipsoidal collapse model of Sheth et al. and approaches the predictions of the spherical collapse model for the rarest halos. Halo bias results based on friends-of-friends halos identified with linking length 0.2 are systematically lower than for halos with the canonical Δ = 200 overdensity by ~10%. In contrast to our previous results on the mass function, we find that the universal bias function evolves very weakly with redshift, if at all. We use our numerical results, both for the mass function and the bias relation, to test the peak-background split model for halo bias. We find that the peak-background split achieves a reasonable agreement with the numerical results, but ~20% residuals remain, both at high and low masses.
|Additional Information:||© 2010 American Astronomical Society. Received 2010 January 18; accepted 2010 September 20; published 2010 November 9. We thank Roman Scoccimarro for sharing his N-body simulations and for the computational resources to analyze them. B.E.R. is supported by a Hubble Fellowship grant, program number HST-HF-51262.01-A provided by NASA from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. A.V.K. is supported by the NSF under grants AST-0239759 and AST-0507666, by NASA through grant NAG5-13274, and by the Kavli Institute for Cosmological Physics at the University of Chicago. Parts of this work were performed under the auspices of the US Department of Energy and supported by its contract No. W-7405- ENG-36 to Los Alamos National Laboratory. Computational resources were provided by the LANL open supercomputing initiative. S.G. acknowledges support by the German Academic Exchange Service. Some of the simulations were performed at the Leibniz Rechenzentrum Munich, partly using German Grid infrastructure provided by AstroGrid-D. The GADGET SPH simulations have been done in the MareNostrum supercomputer at BSC-CNS (Spain) and analyzed at NIC Jülich (Germany). G.Y. and S.G. thank A.I. Hispano-Alemanas and DFG for financial support. G.Y. also acknowledges support from M.E.C. grants FPA2006-01105 and AYA2006-15492-C03.|
|Subject Keywords:||cosmology: theory – large-scale structure of universe – methods: numerical|
|Classification Code:||PACS: 95.35.+d; 98.80.Cq|
|Official Citation:||Jeremy L. Tinker et al. 2010 ApJ 724 878 doi: 10.1088/0004-637X/724/2/878|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Benjamin Perez|
|Deposited On:||10 Jan 2011 22:14|
|Last Modified:||26 Dec 2012 12:50|
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