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The abundance of (not just) dark matter haloes

Sawala, T and Frenk, CS and Crain, RA and Jenkins, A and Schaye, J and Theuns, T and Zavala, J (2013) The abundance of (not just) dark matter haloes. Monthly Notices of the Royal Astronomical Society, 431 (2). pp. 1366-1382. ISSN 0035-8711

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Abstract

We study the effect of baryons on the abundance of structures and substructures in a_cold dark matter (CDM) cosmology, using a pair of high-resolution cosmological simulations from the Galaxies-Intergalactic Medium Interaction Calculation project. Both simulations use identical initial conditions, but while one contains only dark matter, the other also includes baryons.We find that gas pressure, reionization, supernova feedback, stripping and truncated accretion systematically reduce the total mass and the abundance of structures below ∼1012M_ compared to the pure dark matter simulation. Taking this into account and adopting an appropriate detection threshold lower the abundance of observed galaxies with maximum circular velocities
vmax < 100 km s−1, significantly reducing the reported discrepancy between _CDM and the measured H I velocity function of the Arecibo Legacy Fast ALFA survey. We also show that the stellar-to-total mass ratios of galaxies with stellar masses of ∼105–107M_ inferred from abundance matching of the (sub) halo mass function to the observed galaxy mass function increase by a factor of ∼2. In addition, we find that an important fraction of low-mass subhaloes are completely devoid of stars. Accounting for the presence of dark subhaloes below 1010M_ further reduces the abundance of observable objects and leads to an additional increase in the inferred stellar-to-total mass ratio by factors of 2–10 for galaxies in haloes of 109–1010M_. This largely reconciles the abundance matching results with the kinematics of individual dwarf galaxies in_CDM.We propose approximate corrections to the masses of objects derived from pure dark matter calculations to account for baryonic effects.

Item Type: Article
Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Till Sawala, Carlos S. Frenk, Robert A. Crain, Adrian Jenkins, Joop Schaye, Tom Theuns, and Jesus Zavala. The abundance of (not just) dark matter haloes MNRAS (May 11, 2013) Vol. 431 1366-1382 doi:10.1093/mnras/stt259 first published online March 8, 2013 is available online at: http://dx.doi.org/10.1093/mnras/stt259
Uncontrolled Keywords: 0201 Astronomical And Space Sciences
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 31 Oct 2016 12:13
Last Modified: 07 Sep 2017 06:05
DOI or Identification number: 10.1093/mnras/stt259
URI: http://researchonline.ljmu.ac.uk/id/eprint/4698

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