Correlated anisotropies in the cosmic far-infrared background detected by the multiband imaging photometer for spitzer:: Constraint on the bias

We report the detection of correlated anisotropies in the cosmic far-infrared background at 160 mm. We measure the power spectrum in the SWIRE Lockman Hole field. It reveals unambiguously a strong excess above cirrus and Poisson contributions, at spatial scales between 5' and 30', interpreted as the signature of infrared galaxy clustering. Using our model of infrared galaxy evolution, we derive a linear bias. It is a factor b = 1.74 +/- 0.16 2 higher than the bias measured for the local IRAS galaxies. Our model indicates that galaxies dominating the 160 mu m correlated anisotropies are at z similar to 1. This implies that infrared galaxies at high redshifts are biased tracers of mass, unlike in the local universe.