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

Journal Article · Sat Nov 10 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/759/2/92· OSTI ID:22086424

Sutter, P M ^[1]

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1. Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

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.

• OSTI ID: 22086424
• Journal Information: Astrophysical Journal, Vol. 759, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

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