Constraints on Extragalactic Point Source Flux from Diffuse Neutrino Limits

Understand

We constrain the maximum flux from extragalactic neutrino point sources by using diffuse neutrino flux limits.

• We show that the maximum flux from extragalactic point sources is E^2(dN/dE) < 1.4 x 10^-9 (L_nu/2x10^43 erg/s)^1/3 GeV cm-^2 s^-1 from individual point sources with average neutrino luminosity per decade, L_nu.
• It depends only slightly on factors such as the inhomogeneous matter density distribution in the local universe, the luminosity distribution, and the assumed spectral index.
• The derived constraints are at least one order of magnitude below the current experimental limits from direct searches.