Baryon impact on the halo mass function: Fitting formulae and implications for cluster cosmology

By S. Bocquet, A. Saro, Klaus Dolag, Joseph J. Mohr. 2015

168 citations recorded by the source corpus.

We use a set of hydrodynamical and dark matter-only (DMonly) simulations to calibrate the halo mass function (HMF). We explore the impact of baryons, propose an improved parametrization for spherical overdensity masses, and identify differences between our DMonly HMF and previously published HMFs. We use the Magneticum simulations, which are well suited because of their accurate treatment of baryons, high resolution, and large cosmological volumes of up to (3818 Mpc)(3). Baryonic effects globally decrease the masses of galaxy clusters, which, at a given mass, results in a decrease of their number density. This effect vanishes at high redshift z similar to 2 and for high masses M-200m greater than or similar to 10(14)M(circle dot). We perform cosmological analyses of three idealized approximations to the cluster surveys by the South Pole Telescope (SPT), Planck, and eROSITA. We pursue two main questions. (1) What is the impact of baryons? - for the SPT-like and the Planck-like samples, the impact of baryons on cosmological results is negligible. In the eROSITA-like case, however, neglecting the baryonic impact leads to an underestimate of Omega(m) by about 0.01, which is comparable to the expected uncertainty from eROSITA. (2) How does our DMonly HMF compare with previous work? - for the Planck-like sample, results obtained using our DMonly HMF are shifted by Delta(sigma(8)) similar or equal to (sigma(8)(Omega(m)/0.27)(0.3)) similar or equal to 0.02 with respect to results obtained using the Tinker et al. fit. This suggests that using our HMF would shift results from Planck clusters towards better agreement with cosmic-microwave-background anisotropy measurements. Finally, we discuss biases that can be introduced through inadequate HMF parametrizations that introduce false cosmological sensitivity.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/97b5a7d583d61a84f6c98867aff9baa51d0159e3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

Cluster Cosmology Constraints from the 2500 deg2 SPT-SZ Survey: Inclusion of Weak Gravitational Lensing Data from Magellan and the Hubble Space Telescope (2018, methodology): “As discussed in Bocquet et al. (2015) and explicitly shown in their Appendix, we rewrite the first term in Equation (12) as pP Y g z, , , pi i Y g dN z d dz zX t , , ,i i i iX t x ´ x x x ( ∣ )∣ ∣( ∣ ) .”
Weak Lensing Measurement of the Mass--Richness Relation of SDSS redMaPPer Clusters (2016, methodology): “Simulations that include baryonic cooling as well as AGN feedback have been used to study the impact of baryons on halo profiles (e.g., Schaller et al. 2015; Cui et al. 2016b; Bocquet et al. 2016).”
First results from the IllustrisTNG simulations: the stellar mass content of groups and clusters of galaxies (2017, background): “At the current epoch, objects of mass 1014 (1015) M are about 50 (a few thousand) times rarer than Milky-Way like haloes (1012 M ; e.g. Skillman et al. 2014), and they were about ten (a hundred) times more infrequent at z ∼ 1 than today (e.g. Bocquet et al. 2016).”
Phantom: A Smoothed Particle Hydrodynamics and Magnetohydrodynamics Code for Astrophysics (2017, unknown): “…Phantom does not yet compete with gadget variants in terms of the ability to use large numbers of particles (e.g. the most recent calculations by Bocquet et al. (2016) employed more than 1011 particles), since almost all of our published simulations to date have been performed with the OpenMP…”