LiteBIRD Science Goals and Forecasts: Improving Sensitivity to Inflationary Gravitational Waves with Multitracer Delensing
Creators: name: Namikawa, T.
name: Lonappan, A. I.
name: Baccigalupi, C.
name: Bartolo, N.
name: Beck, D.
name: Benabed, K.
name: Challinor, A.
name: Diego-Palazuelos, P.
name: Errard, J.
name: Farrens, S.
name: Gruppuso, A.
name: Krachmalnicoff, N.
name: Migliaccio, M.
name: Martínez-González, E.
name: Pettorino, V.
name: Piccirilli, G.
name: Ruiz-Granda, M.
name: Sherwin, B.
name: Starck, J.
name: Vielva, P.
name: Akizawa, R.
name: Anand, A.
name: Aumont, J.
name: Aurlien, R.
name: Azzoni, S.
name: Ballardini, M.
name: Banday, A. J.
name: Barreiro, R. B.
name: Bersanelli, M.
name: Blinov, D.
name: Bortolami, M.
name: Brinckmann, T.
name: Calabrese, E.
name: Campeti, P.
name: Carones, A.
name: Carralot, F.
name: Casas, F. J.
name: Cheung, K.
name: Clermont, L.
name: Columbro, F.
name: Conenna, G.
name: Coppolecchia, A.
name: Cuttaia, F.
name: D'Alessandro, G.
name: de Bernardis, P.
name: de Haan, T.
name: De Petris, M.
name: Della Torre, S.
name: Di Giorgi, E.
name: Eriksen, H. K.
name: Finelli, F.
name: Franceschet, C.
name: Fuskeland, U.
name: Galloni, G.
name: Galloway, M.
name: Georges, M.
name: Gerbino, M.
name: Gervasi, M.
name: Ghigna, T.
name: Giardiello, S.
name: Gimeno-Amo, C.
name: Gjerløw, E.
name: Hazumi, M.
name: Henrot-Versillé, S.
name: Hergt, L. T.
name: Hivon, E.
name: Kohri, K.
name: Komatsu, E.
name: Lamagna, L.
name: Lattanzi, M.
name: Leloup, C.
name: Lembo, M.
name: López-Caniego, M.
name: Luzzi, G.
name: Maffei, B.
name: Masi, S.
name: Massa, M.
name: Matarrese, S.
name: Matsumura, T.
name: Micheli, S.
name: Moggi, A.
name: Monelli, M.
name: Montier, L.
name: Morgante, G.
name: Mot, B.
name: Mousset, L.
name: Nagata, R.
name: Natoli, P.
name: Novelli, A.
name: Obata, I.
name: Occhiuzzi, A.
name: Pagano, L.
name: Paiella, A.
name: Paoletti, D.
name: Pascual-Cisneros, G.
name: Pavlidou, V.
name: Piacentini, F.
name: Pinchera, M.
name: Pisano, G.
name: Polenta, G.
name: Puglisi, G.
name: Remazeilles, M.
name: Ritacco, A.
name: Rizzieri, A.
name: Rubino-Martin, J.
name: Sakurai, Y.
name: Scott, D.
name: Shiraishi, M.
name: Signorelli, G.
name: Stever, S. L.
name: Takase, Y.
name: Tanimura, H.
name: Tartari, A.
name: Tassis, K.
name: Terenzi, L.
name: Tristram, M.
name: Vacher, L.
name: van Tent, B.
name: Wehus, I. K.
name: Weymann-Despres, G.
name: Zannoni, M.
name: Zhou, Y.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We estimate the efficiency of mitigating the lensing $B$-mode polarization, the so-called delensing, for the $LiteBIRD$ experiment with multiple external data sets of lensing-mass tracers. The current best bound on the tensor-to-scalar ratio, $r$, is limited by lensing rather than Galactic foregrounds. Delensing will be a critical step to improve sensitivity to $r$ as measurements of $r$ become more and more limited by lensing. In this paper, we extend the analysis of the recent $LiteBIRD$ forecast paper to include multiple mass tracers, i.e., the CMB lensing maps from $LiteBIRD$ and CMB-S4-like experiment, cosmic infrared background, and galaxy number density from $Euclid$- and LSST-like survey. We find that multi-tracer delensing will further improve the constraint on $r$ by about $20\%$. In $LiteBIRD$, the residual Galactic foregrounds also significantly contribute to uncertainties of the $B$-modes, and delensing becomes more important if the residual foregrounds are further reduced by an improved component separation method.
description: 21 pages, 7 figures