Article
Astronomy & Astrophysics
Frank J. Qu, Anthony Challinor, Blake D. Sherwin
Summary: This paper studies shear-only estimators and multipole estimators and explores separable approximations based on singular-value decomposition. Through simulation experiments, the efficacy of these methods in suppressing extragalactic foreground biases is verified.
Article
Astronomy & Astrophysics
Noah Sailer, Simone Ferraro, Emmanuel Schaan
Summary: Extragalactic foregrounds cause significant biases in temperature-based cosmic microwave background (CMB) lensing reconstruction. Techniques like source hardening and shear-only estimators effectively reduce foreground-induced biases. This study extends these techniques to polarization and analytically investigates the origin, scaling, and sensitivity of foreground biases in the large-lens limit. Simulations show that biases to Simons Observatory reconstruction are negligible, but those to CMB-S4 reconstruction could be non-negligible at small scales. An optimal linear combination of point-source hardened estimators can significantly reduce bias in CMB lensing power spectrum for a CMB-S4-like experiment.
Article
Astronomy & Astrophysics
Zhengyi Wang, Ji Yao, Xiangkun Liu, Dezi Liu, Zuhui Fan, Bin Hu
Summary: We conducted a forecast study on the cross-correlation between cosmic shear tomography from CSST and CMB lensing from AliCPT-1 in Tibet. By generating correlated galaxy and CMB lensing signals, we accounted for various sources of error and estimated the cross-spectra in four tomographic bins. The total cross-correlation SNR was found to be approximately 15 (AliCPT-1 '4 modules*yr') and 22 (AliCPT-1 '48 modules*yr').
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Ye-Peng Yan, Guo-Jian Wang, Si-Yu Li, Jun-Qing Xia
Summary: Primordial B-mode detection is a major goal of next-generation cosmic microwave background (CMB) experiments. The detection and removal of the lensing effect is crucial to accurately measure the primordial B-mode signal and improve the constraint of primordial gravitational waves (PGWs). In this study, a deep convolutional neural network model called MIMO-UNet is introduced for CMB delensing, which achieves promising results in reconstructing the unlensed CMB polarization maps and recovering the primordial E-mode and B-mode power spectra.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
Alexandre Adam, Laurence Perreault-Levasseur, Yashar Hezaveh, Max Welling
Summary: In this study, a neural network-based recurrent inference machine is used to simultaneously reconstruct undistorted images of background sources and lens mass density distributions. The method effectively optimizes the likelihood given the data using a physical model and learns a prior through neural network training. Compared to traditional parametric models, this approach is more expressive and capable of reconstructing complex mass distributions.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
R. Aurich, D. Reinhardt
Summary: The study investigates the use of invariant scalar measures derived from first and second order covariant derivatives on the sphere to detect distortions in the observed CMB sky map caused by the aberration effect at high multipoles, providing an independent method for determining our peculiar velocity. The eigenvalues of the Hessian matrix of the temperature field are found to be well suited for this task.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Juan Cayuso, Richard Bloch, Selim C. Hotinli, Matthew C. Johnson, Fiona McCarthy
Summary: The kSZ and moving lens effects in the CMB carry important cosmological information. Previous work identified a promising method to extract this information using quadratic estimators. This study assesses the challenges to velocity reconstruction posed by foregrounds and systematics, and develops a numerical code to compute accurately correlated spectra for all components of the CMB and a redshift survey.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Physics, Multidisciplinary
Cara Giovanetti, Mariangela Lisanti, Hongwan Liu, Joshua T. Ruderman
Summary: Dark sectors provide a theoretical framework for studying thermally-produced low-energy dark matter, and these sectors can be constrained by measuring cosmic background radiation and early universe elemental abundances.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
Tirthankar Roy Choudhury, Suvodip Mukherjee, Sourabh Paul
Summary: By comparing predictions of a physical seminumerical model with CMB data, constraints on allowed reionization histories were studied, leading to the determination of tight constraints on parameters such as reionization duration and halo mass. Analysis showed implications for future CMB surveys and 21 cm studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Anton Baleato Lizancos, Anthony Challinor, Blake D. Sherwin, Toshiya Namikawa
Summary: The most promising avenue for detecting primordial gravitational waves from cosmic inflation is through measurements of degree-scale cosmic microwave background (CMB) B-mode polarization. However, the challenge lies in the gravitational lensing effects that obscure the signal of interest. Foregrounds can bias the power spectrum of delensed B-modes, but mitigation techniques based on multifrequency cleaning appear to be very effective.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
L. Gelo, C. J. A. P. Martins, N. Quevedo, A. M. M. Vieira
Summary: The redshift dependence of the cosmic microwave background temperature has important implications for fundamental cosmology, and its constraining power is comparable to other background cosmology probes.
Article
Astronomy & Astrophysics
Dustin R. Madison
Summary: This study develops a formalism to describe how gravitational wave bursts with memory (BWMs) influence the spatial pattern of temperature fluctuations in the cosmic microwave background (CMB). Toy models are used to show how BWMs mix power from spherical harmonic modes of different degrees into various other modes, providing important tools for future analyses incorporating the physics underlying the CMB.
Article
Astronomy & Astrophysics
Peter Adshead, Niayesh Afshordi, Emanuela Dimastrogiovanni, Matteo Fasiello, Eugene A. Lim, Gianmassimo Tasinato
Summary: Characterizing the physical properties of the SGWB, focusing on anisotropies, can be an effective probe of early universe physics by cross correlating with the CMB. This can provide a smoking gun for primordial SGWB anisotropies.
Article
Astronomy & Astrophysics
Louis Legrand, Julien Carron
Summary: Precise reconstruction of the cosmic microwave background lensing potential can be achieved by iteratively removing lensing-induced B modes using deep polarization surveys. A lensing spectrum estimator and its likelihood are introduced to improve the robustness of the estimator to uncertainties in the data modeling. Map-based reconstructions demonstrate unbiased recovery of cosmology and improved constraints on lensing amplitude compared to traditional methods.
Article
Astronomy & Astrophysics
Alessia Ritacco, Francois Boulanger, Vincent Guillet, Jean-Marc Delouis, Jean-Loup Puget, Jonathan Aumont, Leo Vacher
Summary: The study focuses on the separation of the B-modes of the cosmic microwave background from the dust signal. The power-spectra analysis of Planck data is conducted to improve the characterization of the dust spectral energy distribution in polarization. Residual maps and power spectra reveal the complexity of the dust polarized CMB foreground and emphasize the need for refined dust modeling and understanding of polarization-angle variations.
ASTRONOMY & ASTROPHYSICS
(2023)