IceCube expectations for two high-energy neutrino production models at active galactic nuclei

C. A. Argüelles; M. Bustamante; A. M. Gago

doi:10.1088/1475-7516/2010/12/005

IceCube expectations for two high-energy neutrino production models at active galactic nuclei

C. A. Argüelles, M. Bustamante, A. M. Gago

8 Citationer (Scopus)

Abstract

We have determined the currently allowed regions of the parameter spaces of two representative models of diffuse neutrino flux from active galactic nuclei (AGN): one by Koers & Tinyakov (KT) and another by Becker & Biermann (BB). Our observable has been the number of upgoing muon-neutrinos expected in the 86-string IceCube detector, after 5 years of exposure, in the range 10 ⁵ ≤ E_ν/GeV ≤ 10⁸. We have used the latest estimated discovery potential of the IceCube-86 array at the 5σ level to determine the lower boundary of the regions, while for the upper boundary we have used either the AMANDA upper bound on the neutrino flux or the more recent preliminary upper bound given by the half-completed IceCube-40 array (IC40). We have varied the spectral index of the proposed power-law fluxes, α, and two parameters of the BB model: the ratio between the boost factors of neutrinos and cosmic rays, Γ_ν/Γ_CR, and the maximum redshift of the sources that contribute to the cosmic-ray flux, z^max_CR. For the KT model, we have considered two scenarios: one in which the number density of AGN does not evolve with redshift and another in which it evolves strongly, following the star formation rate. Using the IC40 upper bound, we have found that the models are visible in IceCube-86 only inside very thin strips of parameter space and that both of them are discarded at the preferred value of γ = 2.7 obtained from fits to cosmic-ray data. Lower values of γ, notably the values 2.0 and 2.3 proposed in the literature, fare better. In addition, we have analysed the capacity of IceCube-86 to discriminate between the models within the small regions of parameter space where both of them give testable predictions. Within these regions, discrimination at the 5σ level or more is guaranteed.

Originalsprog	Engelsk
Artikelnummer	005
Tidsskrift	Journal of Cosmology and Astroparticle Physics
Vol/bind	2010
Udgave nummer	12
ISSN	1475-7516
DOI	https://doi.org/10.1088/1475-7516/2010/12/005
Status	Udgivet - dec. 2010
Udgivet eksternt	Ja

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10.1088/1475-7516/2010/12/005

http://iopscience.iop.org/article/10.1088/1475-7516/2010/12/005/pdf

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title = "IceCube expectations for two high-energy neutrino production models at active galactic nuclei",

abstract = "We have determined the currently allowed regions of the parameter spaces of two representative models of diffuse neutrino flux from active galactic nuclei (AGN): one by Koers & Tinyakov (KT) and another by Becker & Biermann (BB). Our observable has been the number of upgoing muon-neutrinos expected in the 86-string IceCube detector, after 5 years of exposure, in the range 10 5 ≤ Eν/GeV ≤ 108. We have used the latest estimated discovery potential of the IceCube-86 array at the 5σ level to determine the lower boundary of the regions, while for the upper boundary we have used either the AMANDA upper bound on the neutrino flux or the more recent preliminary upper bound given by the half-completed IceCube-40 array (IC40). We have varied the spectral index of the proposed power-law fluxes, α, and two parameters of the BB model: the ratio between the boost factors of neutrinos and cosmic rays, Γν/ΓCR, and the maximum redshift of the sources that contribute to the cosmic-ray flux, zmaxCR. For the KT model, we have considered two scenarios: one in which the number density of AGN does not evolve with redshift and another in which it evolves strongly, following the star formation rate. Using the IC40 upper bound, we have found that the models are visible in IceCube-86 only inside very thin strips of parameter space and that both of them are discarded at the preferred value of γ = 2.7 obtained from fits to cosmic-ray data. Lower values of γ, notably the values 2.0 and 2.3 proposed in the literature, fare better. In addition, we have analysed the capacity of IceCube-86 to discriminate between the models within the small regions of parameter space where both of them give testable predictions. Within these regions, discrimination at the 5σ level or more is guaranteed.",

keywords = "astro-ph.HE, hep-ph",

author = "Arg{\"u}elles, {C. A.} and M. Bustamante and Gago, {A. M.}",

note = "24 pages, 6 figures, v2: new IceCube-40 astrophysical neutrino upper bound and IceCube-86 discovery potential used, explanation of AGN flux models improved, only upgoing neutrinos used, conclusions strengthened. Accepted for publication in JCAP",

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T1 - IceCube expectations for two high-energy neutrino production models at active galactic nuclei

AU - Argüelles, C. A.

AU - Bustamante, M.

AU - Gago, A. M.

N1 - 24 pages, 6 figures, v2: new IceCube-40 astrophysical neutrino upper bound and IceCube-86 discovery potential used, explanation of AGN flux models improved, only upgoing neutrinos used, conclusions strengthened. Accepted for publication in JCAP

PY - 2010/12

Y1 - 2010/12

N2 - We have determined the currently allowed regions of the parameter spaces of two representative models of diffuse neutrino flux from active galactic nuclei (AGN): one by Koers & Tinyakov (KT) and another by Becker & Biermann (BB). Our observable has been the number of upgoing muon-neutrinos expected in the 86-string IceCube detector, after 5 years of exposure, in the range 10 5 ≤ Eν/GeV ≤ 108. We have used the latest estimated discovery potential of the IceCube-86 array at the 5σ level to determine the lower boundary of the regions, while for the upper boundary we have used either the AMANDA upper bound on the neutrino flux or the more recent preliminary upper bound given by the half-completed IceCube-40 array (IC40). We have varied the spectral index of the proposed power-law fluxes, α, and two parameters of the BB model: the ratio between the boost factors of neutrinos and cosmic rays, Γν/ΓCR, and the maximum redshift of the sources that contribute to the cosmic-ray flux, zmaxCR. For the KT model, we have considered two scenarios: one in which the number density of AGN does not evolve with redshift and another in which it evolves strongly, following the star formation rate. Using the IC40 upper bound, we have found that the models are visible in IceCube-86 only inside very thin strips of parameter space and that both of them are discarded at the preferred value of γ = 2.7 obtained from fits to cosmic-ray data. Lower values of γ, notably the values 2.0 and 2.3 proposed in the literature, fare better. In addition, we have analysed the capacity of IceCube-86 to discriminate between the models within the small regions of parameter space where both of them give testable predictions. Within these regions, discrimination at the 5σ level or more is guaranteed.

AB - We have determined the currently allowed regions of the parameter spaces of two representative models of diffuse neutrino flux from active galactic nuclei (AGN): one by Koers & Tinyakov (KT) and another by Becker & Biermann (BB). Our observable has been the number of upgoing muon-neutrinos expected in the 86-string IceCube detector, after 5 years of exposure, in the range 10 5 ≤ Eν/GeV ≤ 108. We have used the latest estimated discovery potential of the IceCube-86 array at the 5σ level to determine the lower boundary of the regions, while for the upper boundary we have used either the AMANDA upper bound on the neutrino flux or the more recent preliminary upper bound given by the half-completed IceCube-40 array (IC40). We have varied the spectral index of the proposed power-law fluxes, α, and two parameters of the BB model: the ratio between the boost factors of neutrinos and cosmic rays, Γν/ΓCR, and the maximum redshift of the sources that contribute to the cosmic-ray flux, zmaxCR. For the KT model, we have considered two scenarios: one in which the number density of AGN does not evolve with redshift and another in which it evolves strongly, following the star formation rate. Using the IC40 upper bound, we have found that the models are visible in IceCube-86 only inside very thin strips of parameter space and that both of them are discarded at the preferred value of γ = 2.7 obtained from fits to cosmic-ray data. Lower values of γ, notably the values 2.0 and 2.3 proposed in the literature, fare better. In addition, we have analysed the capacity of IceCube-86 to discriminate between the models within the small regions of parameter space where both of them give testable predictions. Within these regions, discrimination at the 5σ level or more is guaranteed.

KW - astro-ph.HE

KW - hep-ph

U2 - 10.1088/1475-7516/2010/12/005

DO - 10.1088/1475-7516/2010/12/005

M3 - Journal article

SN - 1475-7516

VL - 2010

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

IS - 12

M1 - 005

ER -

IceCube expectations for two high-energy neutrino production models at active galactic nuclei

Abstract

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