Article
Astronomy & Astrophysics
D. Munshi, R. Takahashi, J. D. McEwen
Summary: In this paper, we introduce the response function approach to model weak lensing statistics in the context of separate universe formalism. We present numerical results for RFs in various semi-analytical models and compare them to the Integrated Bispectrum and Trispectrum. We find that due to line-of-sight projection effects, the expressions for RFs differ from squeezed correlation functions. We also generalize the concept of k-cut power spectrum to k-cut response functions and define their counterparts in real space for easier estimation from surveys.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
David Wittman, Matthew Self
Summary: Weak gravitational lensing measurements based on photometry can be limited by shape noise, but using velocity field data for disk galaxies can greatly reduce this noise. Forecasts show that for nearly face-on targets, one shear component can be constrained to a very small range, but the precision decreases with inclination angle.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Giovanni Covone, Mauro Sereno
Summary: This article discusses the gravitational lensing phenomena that occur due to the redshift drift between the lensed source, gravitational lens, and observer. The proximity of the source to the drifting caustics can result in the occurrence or disappearance of a pair of images due to cosmological expansion. Lensing systems act as signal converters, altering the angular position, magnification, distortion, and time delay of existing multiple images.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Chien-Hao Lin, Rachel Mandelbaum, M. A. Troxel, Christopher M. Hirata, Mike Jarvis
Summary: The High-Latitude Survey of the Nancy Grace Roman Space Telescope will provide high-quality weak lensing data with minimal impact from the persistence effect. The effect of persistence on the weak lensing correlation function is expected to be minimal compared to other sources of error in the Roman Space Telescope's measurements.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Joseph M. I. I. Fabritius II, Evan J. Arena, David M. Goldberg
Summary: The study found that galaxies with characteristics of early-type galaxies have lower intrinsic scatter in flexion signal, while late-type galaxies have higher scatter. Using a new gravitational lensing code Lenser, the measured flexion noise can be reduced by more than a factor of two at both low and high redshifts.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
A. Niemiec, M. Jauzac, D. Eckert, D. Lagattuta, K. Sharon, A. M. Koekemoer, K. Umetsu, A. Acebron, J. M. Diego, D. Harvey, E. Jullo, V Kokorev, M. Limousin, G. Mahler, P. Natarajan, M. Nonino, C. Steinhardt, S- Tam, A. Zitrin
Summary: The study presents a combined strong and weak lensing analysis of the Abell 370 cluster using the HST BUFFALO program. Seven candidate substructures were identified and evaluated for their physical significance. Five of these candidates were found to be reliable, and the mass distribution in Abell 370 was observed to extend along the north-west and south-east directions. This research provides new insights into the complex mass distribution of clusters at large cluster-centric radii.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Patrick Shaw, Rupert A. C. Croft, R. Benton Metcalf
Summary: We evaluate the performance of the Lyman alpha forest weak gravitational lensing estimator on different types of forest data and investigate its dependence on spectrum signal to noise. The non-linearity and non-Gaussianity in the forest data cause a reduction in signal to noise, and using ray-traced potentials from N-body simulations incurs an additional reduction. We also demonstrate methods for mitigating these issues, such as Gaussianization and bias correction.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Joseph M. Fabritius, Evan J. Arena, David M. Goldberg
Summary: The study found that objects with characteristics consistent with early-type galaxies have lower intrinsic scatter in flexion signal, while late-type galaxies have higher scatter. The measured flexion noise can be reduced by more than a factor of two at both low and high redshifts.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Xianlong He, Kai Liao, Xuheng Ding, Lilan Yang, Xudong Wen, Zhiqiang You, Zong-Hong Zhu
Summary: This study investigates the impact of gravitational lensing on the inference of the black hole mass function (BHMF). The results suggest that the lensing effect can be safely ignored in the foreseeable future, except when focusing on an accurate estimation of the high mass end of the BHMF at high redshifts.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Viraj Nistane, Mona Jalilvand, Julien Carron, Ruth Durrer, Martin Kunz
Summary: In this study, we propose an estimator for the lensing potential using galaxy number counts, which includes a linear and a quadratic term. Our results demonstrate that this estimator has a significantly higher signal-to-noise ratio compared to the corresponding estimator from intensity mapping. The improved signal-to-noise ratio is attributed to the additional lensing term in the number count angular power spectrum, which appears at linear order. We estimate the signal-to-noise ratio for future photometric surveys and find that it can reach an order of magnitude of 30, particularly at high redshifts (z greater than or similar to 1.5). Therefore, we argue that number counts in photometric surveys are an excellent tool for measuring tomographic lensing spectra.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Kai Liao
Summary: This study examines the impact of microlensing on strong lens time-delay cosmography and proposes a method to reduce bias through a designed observation strategy. The results indicate that long time monitoring of images and using bluer bands can decrease the time-delay dispersions caused by microlensing.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Leonardo Giani, Cullan Howlett, Rossana Ruggeri, Federico Bianchini, Khaled Said, Tamara M. Davis
Summary: We investigate the cross correlation between radial peculiar velocities (PV) and lensing convergence of cosmic microwave background (CMB) photons for the first time. The theoretical expectations for the signal and its covariance are derived and the detectability with existing and forthcoming surveys is assessed. The study reveals that such cross-correlations can improve constraints on gravitational models by breaking degeneracies with matter density. Additionally, the distance-scaling dispersion of peculiar velocities is identified as the main source of noise in the cross correlation. When assuming a redshift-independent scatter for PV, the study shows that the cross correlation may be detected in the future using PV measurements from DESI and convergence map from CMB-S4.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Jeremie Francfort, Ruth Durrer, Giulia Cusin
Summary: This paper introduces a new observable to measure cosmic shear, which is sensitive to the angle between the orientation of a galaxy and the polarization direction of its radio emission. Despite the expected low signal-to-noise ratio for a single measurement, the fact that all galaxies in a given pixel experience the same shear allows to overcome the noise. Another advantage of this method is that the signal is not affected by intrinsic alignment.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Mathew S. Madhavacheril, Kendrick M. Smith, Blake D. Sherwin, Sigurd Naess
Summary: The power spectrum of cosmic microwave background (CMB) lensing will be measured with high precision in upcoming surveys, allowing for constraints on neutrino masses and cosmological parameters. A new estimator is proposed in this study that is robust against assumptions made in modeling or simulating instrument noise, providing efficient computation without substantial loss in signal-to-noise ratio. This new method relies on multiple splits of CMB maps with independent instrument noise to improve the accuracy of lensing power spectrum measurements.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Christos Georgiou, Henk Hoekstra, Konrad Kuijken, Maciej Bilicki, Andrej Dvornik, Thomas Erben, Benjamin Giblin, Catherine Heymans, Hendrik Hildebrandt, Jelte T. A. de Jong, Arun Kannawadi, Peter Schneider, Tim Schrabback, Huan Yuan Shan, Angus H. Wright
Summary: The study measured the alignment ratio of the ellipticities of central galaxies using weak gravitational lensing data, finding that outer galaxy regions are more aligned with their dark matter halos than the inner regions. The results suggest that lower mass halos may be rounder and/or less aligned with their host galaxy compared to more massive galaxies.
ASTRONOMY & ASTROPHYSICS
(2021)