Probing the rest-frame of the Universe with the near-IR cosmic infrared background

ABSTRACT While the cosmic microwave background (CMB) dipole is largely assumed to be entirely kinematic, there evidence that part of it primordial. Such a possibility arises in models implying tilt, interpreted as dark flow, across observable Universe. The kinematic nature entire CMB can probed using backgrounds from galaxies after last scattering. near-infrared (near-IR) infrared (CIB) spectral energy distribution leads an amplified compared with CMB. CIB affected by galaxy clustering, decreasing fainter, more distant galaxies, and Solar System emissions Galactic dust, which dominate net cosmological optical/near-IR. We propose technique enables accurate measurement near-IR dipole. CIB, effectively integrated light (IGL), would reconstructed resolved forthcoming space-borne wide surveys covering four bands, 0.9–2.5 μm. will subselected identified magnitude range where component clustering below expected Using this technique, measured each bands at statistical signal-to-noise ratio S/N ≳50–100 Euclid Roman surveys, isolating dipole’s nature.