The Mass Function of Unprocessed Dark Matter Halos and Merger Tree Branching Rates

Abstract

A common approach in semi-analytic modeling of galaxy formation is to construct Monte Carlo realizations of merger histories of dark matter halos whose masses are sampled from a halo mass function. Both the mass function itself, and the merger rates used to construct merging histories are calibrated to N-body simulations. Typically, "backsplash" halos (those which were once subhalos within a larger halo, but which have since moved outside of the halo) are counted in both the halo mass function, and in the merger rates (or, equivalently, progenitor mass functions). This leads to a double-counting of mass in Monte Carlo merger histories which will bias results relative to N-body results. We measure halo mass functions and merger rates with this double-counting removed in a large, cosmological N-body simulation with cosmological parameters consistent with current constraints. Furthermore, we account for the inherently noisy nature of N-body halo mass estimates when fitting functions to N-body data, and show that ignoring these errors leads to a significant systematic bias given the precision statistics available from state-of-the-art N-body cosmological simulations.

13 pages, submitted to MNRAS, comments welcome

References in corpus (8)

• The redshift dependence of the structure of massive LCDM halos
• The halo mass function from the dark ages through the present day
• The Halo Mass Function: High-Redshift Evolution and Universality
• The Unorthodox Orbits of Substructure Halos
• The statistical properties of LCDM halo formation
• Building a Predictive Model of Galaxy Formation - I: Phenomenological Model Constrained to the $z=0$ Stellar Mass Function
• The Tidal Streams of Disrupting Subhaloes in Cosmological Dark Matter Haloes
• Quantifying and controlling biases in dark matter halo concentration estimates

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• Fluctuations of the gravitational field generated by a random population of extended substructures
• The Normalization and Slope of the Dark Matter (Sub-)Halo Mass Function on Sub-Galactic Scales
• Core Formation in High-z Massive Haloes: Heating by Post Compaction Satellites and Response to AGN Outflows
• Halo concentrations from extended Press-Schechter merger histories