http://arxiv.org/abs/1505.04418
IceCube has detected the diffuse TeV-PeV neutrino emission, for which the flat spectrum radio quasars (FSRQs) have been proposed to be the strong candidate sources. Here we assume that there is a correlation between the gamma-ray and neutrino fluxes from FSRQs, and use the \textit{Fermi}-LAT detected gamma-ray flux from FSRQs to constrain their neutrino flux, and then test if they can account for the diffuse neutrino emission. We first obtain the gamma-ray/neutrino flux ratio by the diffuse gamma-ray flux from \textit{Fermi}-LAT observations of FSRQs and the diffuse neutrino flux from IceCube detection, then apply this ratio to individual FSRQs, and predict their neutrino flux, to be compared with the upper limits that IceCube provides for individual FSRQs, especially those in the northern sky with more stringent constraint by IceCube. We find that a large fraction of candidate FSRQs from the northern sky in the IceCube point source search has predicted neutrino flux violating the IceCube limit, and in the stacking search the predicted neutrino flux of the FSRQs in the northern sky is close to the current IceCube limit. The sensitivity of IceCube after several years of running time may reach the level that can clearly examine the FSRQ origin of the diffuse neutrino emission. The caveat in the assumptions are also discussed.
B. Wang and Z. Li
Tue, 19 May 15
12/78
Comments: 13 pages, 2 figures
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