The peculiar motion of an observer relative to an ideal reference frame at rest with respect to the cosmic background produces boosting effects which modify and transfer at higher multipoles the frequency spectrum of the isotropic background. Analytical solutions of a system of linear equations are presented to explicitly compute the spherical harmonic expansion coefficients for background spectra described by analytical or semi-analytical functions, significantly alleviating the computational effort needed for accurate theoretical predictions. This approach is extended to generic (tabulated) functions, allowing to treat a wider range of realistic models. Precise inter-frequency calibration will provide the opportunity to constrain or even detect tiny imprints in the background spectrum from a variety of cosmological and astrophysical processes, mainly due to the frequency dependence of the dipole spectrum, without resorting to precise absolute calibration. Expectations of future all-sky differential surveys in retrieving the amplitude of the far-infrared background spectrum and the parameters of the cosmic microwave background spectral distortions are discussed. In principle, the presence of spectral distortions also offers the chance to alleviate, with dipole analyses alone, the degeneracy between intrinsic and kinetic dipoles. The dipole signal on small sky areas expected at radio frequencies from a variety of processes is compared with the sensitivity and resolution of next interferometric observations.
11/04/2024
The speaker is: Carlo BURIGANA (INAF/IRA)
Thursday, April 11th at 11:30
The seminar can be attended in person in Sala Jappelli or remotely through the zoom link:
Join Zoom Meeting
https://unipd.zoom.us/j/85273198731?pwd=V1ZiNE9ZWUN4ZTdIUzJsTFo0Z3U2Zz09
Meeting ID: 852 7319 8731
Passcode: 208186