Journal
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume 520, Issue 2, Pages 3164-3186Publisher
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stad342
Keywords
hydrodynamics - methods; numerical - software; simulations - galaxies; clusters - galaxies; fundamental parame-ters - galaxies
Categories
Ask authors/readers for more resources
Recent cosmological simulations predict high entropy levels in the intra-cluster medium, contradicting X-ray observations. This study investigates the impact of different sub-grid models on the central entropy and profile shape in zoom-in cosmological simulations using the EAGLE galaxy formation model. The results indicate that changes in the sub-grid models can affect the entropy levels and profile shape.
Recent high-resolution cosmological hydrodynamic simulations run with a variety of codes systematically predict large amounts of entropy in the intra-cluster medium at low redshift, leading to flat entropy profiles and a suppressed cool-core population. This prediction is at odds with X-ray observations of groups and clusters. We use a new implementation of the EAGLE galaxy formation model to investigate the sensitivity of the central entropy and the shape of the profiles to changes in the sub-grid model applied to a suite of zoom-in cosmological simulations of a group of mass M-500 = 8.8 x 10(12) M-? and a cluster of mass 2.9 x 10(14) M-? Using our reference model, calibrated to match the stellar mass function of field galaxies, we confirm that our simulated groups and clusters contain hot gas with too high entropy in their cores. Additional simulations run without artificial conduction, metal cooling or active galactic nuclei (AGN) feedback produce lower entropy levels but still fail to reproduce observed profiles. Conversely, the two objects run without supernova feedback show a significant entropy increase which can be attributed to excessive cooling and star formation. Varying the AGN heating temperature does not greatly affect the profile shape, but only the overall normalization. Finally, we compared runs with four AGN heating schemes and obtained similar profiles, with the exception of bipolar AGN heating, which produces a higher and more uniform entropy distribution. Our study leaves open the question of whether the entropy core problem in simulations, and particularly the lack of power-law cool-core profiles, arise from incorrect physical assumptions, missing physical processes, or insufficient numerical resolution.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available