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Title: A FIRST ESTIMATE OF RADIO HALO STATISTICS FROM LARGE-SCALE COSMOLOGICAL SIMULATION

Abstract

We present a first estimate based on a cosmological gas dynamics simulation of galaxy cluster radio halo counts to be expected in forthcoming low-frequency radio surveys. Our estimate is based on a FLASH simulation of the {Lambda}CDM model for which we have assigned radio power to clusters via a model that relates radio emissivity to cluster magnetic field strength, intracluster turbulence, and density. We vary several free parameters of this model and find that radio halo number counts vary by up to a factor of two for average magnetic fields ranging from 0.2 to 3.1 {mu}G. However, we predict significantly fewer low-frequency radio halos than expected from previous semi-analytic estimates, although this discrepancy could be explained by frequency-dependent radio halo probabilities as predicted in reacceleration models. We find that upcoming surveys will have difficulty in distinguishing models because of large uncertainties and low number counts. Additionally, according to our modeling we find that expected number counts can be degenerate with both reacceleration and hadronic secondary models of cosmic-ray generation. We find that relations between radio power and mass and X-ray luminosity may be used to distinguish models, and by building mock radio sky maps we demonstrate that surveys such asmore » LOFAR may have sufficient resolution and sensitivity to break this model degeneracy by imaging many individual clusters.« less

Authors:
 [1];  [2]
  1. Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)
  2. Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)
Publication Date:
OSTI Identifier:
22086424
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 759; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COMPUTERIZED SIMULATION; COSMIC PHOTONS; COSMOLOGICAL CONSTANT; COSMOLOGICAL MODELS; COSMOLOGY; EMISSIVITY; FREQUENCY DEPENDENCE; GALAXY CLUSTERS; HADRONS; HYDRODYNAMICS; INTERSTELLAR MAGNETIC FIELDS; LUMINOSITY; PROBABILITY; RESOLUTION; SENSITIVITY; X RADIATION

Citation Formats

Sutter, P. M., and Ricker, P. M., E-mail: psutter2@illinois.edu, E-mail: pmricker@illinois.edu. A FIRST ESTIMATE OF RADIO HALO STATISTICS FROM LARGE-SCALE COSMOLOGICAL SIMULATION. United States: N. p., 2012. Web. doi:10.1088/0004-637X/759/2/92.
Sutter, P. M., & Ricker, P. M., E-mail: psutter2@illinois.edu, E-mail: pmricker@illinois.edu. A FIRST ESTIMATE OF RADIO HALO STATISTICS FROM LARGE-SCALE COSMOLOGICAL SIMULATION. United States. doi:10.1088/0004-637X/759/2/92.
Sutter, P. M., and Ricker, P. M., E-mail: psutter2@illinois.edu, E-mail: pmricker@illinois.edu. Sat . "A FIRST ESTIMATE OF RADIO HALO STATISTICS FROM LARGE-SCALE COSMOLOGICAL SIMULATION". United States. doi:10.1088/0004-637X/759/2/92.
@article{osti_22086424,
title = {A FIRST ESTIMATE OF RADIO HALO STATISTICS FROM LARGE-SCALE COSMOLOGICAL SIMULATION},
author = {Sutter, P. M. and Ricker, P. M., E-mail: psutter2@illinois.edu, E-mail: pmricker@illinois.edu},
abstractNote = {We present a first estimate based on a cosmological gas dynamics simulation of galaxy cluster radio halo counts to be expected in forthcoming low-frequency radio surveys. Our estimate is based on a FLASH simulation of the {Lambda}CDM model for which we have assigned radio power to clusters via a model that relates radio emissivity to cluster magnetic field strength, intracluster turbulence, and density. We vary several free parameters of this model and find that radio halo number counts vary by up to a factor of two for average magnetic fields ranging from 0.2 to 3.1 {mu}G. However, we predict significantly fewer low-frequency radio halos than expected from previous semi-analytic estimates, although this discrepancy could be explained by frequency-dependent radio halo probabilities as predicted in reacceleration models. We find that upcoming surveys will have difficulty in distinguishing models because of large uncertainties and low number counts. Additionally, according to our modeling we find that expected number counts can be degenerate with both reacceleration and hadronic secondary models of cosmic-ray generation. We find that relations between radio power and mass and X-ray luminosity may be used to distinguish models, and by building mock radio sky maps we demonstrate that surveys such as LOFAR may have sufficient resolution and sensitivity to break this model degeneracy by imaging many individual clusters.},
doi = {10.1088/0004-637X/759/2/92},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}