LiteBIRD Science Goals and Forecasts. Mapping the Hot Gas in the Universe

• Main Authors: Remazeilles, M, Douspis, M, Rubiño-Martín, J. A, Chluba, J, de Bernardis, P, De Petris, M, Hernández-Monteagudo, C, Luzzi, G, Macias-Perez, J, Masi, S, Namikawa, T, Salvati, L, Aizawa, K, Anand, A, Aumont, J, Baccigalupi, C, Ballardini, M, Barreiro, R. B, Basak, S, Bersanelli, M, Blinov, D, Bortolami, M, Brinckmann, T, Calabrese, E, Campeti, P, Carinos, E, Carones, A, Casas, F. J, Cheung, K, Columbro, F, Coppolecchia, A, Cuttaia, F, de Haan, T, de la Hoz, E, Della Torre, S, Diego-Palazuelos, P, D'Alessandro, G, Finelli, F, Fuskeland, U, Galloni, G, Galloway, M, Gervasi, M, Génova-Santos, R. T, Ghigna, T, Giardiello, S, Gimeno-Amo, C, Gjerløw, E, González, R. González, Gruppuso, A, Hazumi, M, Henrot-Versillé, S, Hergt, L. T, Herranz, D, Kohri, K, Komatsu, E, Lamagna, L, Leloup, C, Levrier, F, Lonappan, A. I, López-Caniego, M, Maffei, B, Martínez-González, E, Matarrese, S, Matsumura, T, Micheli, S, Migliaccio, M, Monelli, M, Montier, L, Morgante, G, Nagata, R, Novelli, A, Omae, R, Pagano, L, Paoletti, D, Pavlidou, V, Piacentini, F, Pinchera, M, Polenta, G, Porcelli, L, Ritacco, A, Ruiz-Granda, M, Sakurai, Y, Scott, D, Shiraishi, M, Stever, S. L, Sullivan, R. M, Takase, Y, Tassis, K, Terenzi, L, Tomasi, M, Tristram, M, Vacher, L, van Tent, B, Vielva, P, Wehus, I. K, Westbrook, B, Weymann-Despres, G, Wollack, E. J, Zannoni, M, Zhou, Y
• Format: Journal Article
• Language: English
• Published: 24-07-2024
• Subjects: Physics - Cosmology and Nongalactic Astrophysics
• DOI: 10.48550/arxiv.2407.17555

We assess the capabilities of the LiteBIRD mission to map the hot gas
distribution in the Universe through the thermal Sunyaev-Zeldovich (SZ) effect.
Our analysis relies on comprehensive simulations incorporating various sources
of Galactic and extragalactic foreground emission, while accounting for
specific instrumental characteristics of LiteBIRD, such as detector
sensitivities, frequency-dependent beam convolution, inhomogeneous sky
scanning, and $1/f$ noise. We implement a tailored component-separation
pipeline to map the thermal SZ Compton $y$-parameter over 98% of the sky.
Despite lower angular resolution for galaxy cluster science, LiteBIRD provides
full-sky coverage and, compared to the Planck satellite, enhanced sensitivity,
as well as more frequency bands to enable the construction of an all-sky
$y$-map, with reduced foreground contamination at large and intermediate
angular scales. By combining LiteBIRD and Planck channels in the
component-separation pipeline, we obtain an optimal $y$-map that leverages the
advantages of both experiments, with the higher angular resolution of the
Planck channels enabling the recovery of compact clusters beyond the LiteBIRD
beam limitations, and the numerous sensitive LiteBIRD channels further
mitigating foregrounds. The added value of LiteBIRD is highlighted through the
examination of maps, power spectra, and one-point statistics of the various sky
components. After component separation, the $1/f$ noise from LiteBIRD is
effectively mitigated below the thermal SZ signal at all multipoles.
Cosmological constraints on $S_8=\sigma_8\left(\Omega_{\rm m}/0.3\right)^{0.5}$
obtained from the LiteBIRD-Planck combined $y$-map power spectrum exhibits a
15% reduction in uncertainty compared to constraints from Planck alone. This
improvement can be attributed to the increased portion of uncontaminated sky
available in the LiteBIRD-Planck combined $y$-map.