Figure 1

Constraints on neutrino point fluxes derived from the UHE diffuse $\nu$-flux limit [7], and from VHE limit [11], for two representative $⟨L_{\nu }⟩=({10}^{40},2\times {10}^{43})\mathrm{erg}/\mathrm{s}$. Current AMANDA limit [8], IceCube sensitivity [9] to neutrino point fluxes,and IceCube limits [32] on fluxes from two individual point sources are also shown (thin solid lines). A sample of model predictions for ${\nu }_{\mu }$-point flux from extragalactic sources are displayed in thin dotted-dashed lines, which are proportional to an $E^{-2}$ spectrum or follow a broken power law. Emission from AGN jet, calculated for a 3C279 flare of 1 day period (3C279 19); spectra predicted for Mkn 501 during the outburst in 1997 (Mkn 501 20) and core emission due to $pp$ interactions (3C273 17); radio-quiet AGN (RQQ 22); emission from Cen A as described in Cen A 23, Cen A 24, and Cen A 28; emission from M87 (M87 23), and emission from Coma galaxy cluster (Coma 25).Reuse & Permissions

Figure 2

Same flux constraints as Fig. 1 compared to a sample of model predictions for ${\nu }_{\mu }$-point flux from extragalactic sources are displayed in thin dotted-dashed lines, which strongly differ from an $E^{-2}$ spectrum. Emission from 3C273 predicted by 3C273 16, including $pp$ and $p\gamma$ interactions (3C273 18); core emission due to $p\gamma$ interaction (3C273 26); AGN jet continuous emission (3C279 16); emission from NGC4151 by NGC4151 16 and core emission from NGC4151 due to $p\gamma$ interaction (NGC4151 2); Spectra predicted for Mkn 421 (Mkn 421 16), and blazar flaring Mkn 501 (Mkn 501 21); GeV-loud blazars (GeV blazar [27]).Reuse & Permissions

Figure 3

The number density of neutrino sources $n_s$ plotted versus the expected neutrino luminosity predicted according to the fluxes of the model tested. The derived upper bounds from the diffuse flux show a stronger constraint than the limit from point flux from direct searches. The hatched area represents the limits accessed by the diffuse flux, but not yet accessible by direct measurement from the point source searches. Upper bounds on number density $n_s$ are computed for different neutrino sources (vertical arrows). Thin solid/dotted lines represent [diffuse (D)/point (P)] constraints on the number density with 1 and 2 orders of magnitude improvement. The region above the thick solid line is excluded by the diffuse flux limits.Reuse & Permissions