Cosmic Dark Radiation and Neutrinos

Figure 1

ISW contribution to the CMB temperature power spectrum. The raise at ℓ<30 is due to the late Integrated Sachs Wolfe, while the peak around ℓ∼200 is the early Integrated Sachs Wolfe effect. The cosmological model is the ΛCDM with 𝑁_eff being equal to 3 (black solid line), 5 (red dashed line), and 7 (green dot-dashed line).