QUBIC II: Spectro-Polarimetry with Bolometric Interferometry
astro-ph.IM
/ Authors
L. Mousset, M. M. Gamboa Lerena, E. S. Battistelli, P. de Bernardis, P. Chanial, G. D'Alessandro, G. Dashyan, M. De Petris, L. Grandsire, J. -Ch. Hamilton
and 121 more authors
F. Incardona, S. Landau, S. Marnieros, S. Masi, A. Mennella, C. O'Sullivan, M. Piat, G. Ricciardi, C. G. Scóccola, M. Stolpovskiy, A. Tartari, J. -P. Thermeau, S. A. Torchinsky, F. Voisin, M. Zannoni, P. Ade, J. G. Alberro, A. Almela, G. Amico, L. H. Arnaldi, D. Auguste, J. Aumont, S. Azzoni, S. Banfi
/ Abstract
Bolometric interferometry is a novel technique that has the ability to perform spectral imaging. A bolometric interferometer observes the sky in a wide frequency band and can reconstruct sky maps in several sub-bands within the physical band in post-processing of the data. This provides a powerful spectral method to discriminate between the cosmic microwave background (CMB) and astrophysical foregrounds. In this paper, the methodology is illustrated with examples based on the Q \& U Bolometric Interferometer for Cosmology (QUBIC) which is a ground-based instrument designed to measure the B-mode polarization of the sky at millimeter wavelengths. We consider the specific cases of point source reconstruction and Galactic dust mapping and we characterize the point spread function as a function of frequency. We study the noise properties of spectral imaging, especially the correlations between sub-bands, using end-to-end simulations together with a fast noise simulator. We conclude showing that spectral imaging performance are nearly optimal up to five sub-bands in the case of QUBIC.