Article
Astronomy & Astrophysics
Constance Mahony, Maria Cristina Fortuna, Benjamin Joachimi, Andreas Korn, Henk Hoekstra, Samuel J. Schmidt
Summary: Recent works have shown that weak lensing magnification must be included in large-scale structure analyses to avoid biasing the cosmological results. This study investigates the impact of including magnification on the precision of cosmological constraints in an LSST galaxy clustering analysis and finds that it has little effect on the precision of the constraints.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Mohamed Yousry Elkhashab, Cristiano Porciani, Daniele Bertacca
Summary: The study focuses on the impact of radial redshift-space distortions on the monopole moment of the galaxy power spectrum, demonstrating excess power due to peculiar velocities and a damped oscillatory pattern caused by the kinematic dipole overdensity. It also discusses the weak-lensing magnification effect and potential implications for determining cosmological parameters and properties of the galaxy population.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Marika Asgari, Indiarose Friswell, Mijin Yoon, Catherine Heymans, Andrej Dvornik, Benjamin Joachimi, Patrick Simon, Joe Zuntz
Summary: The study introduces a mitigation strategy to reduce the impact of non-linear galaxy bias on the joint cosmological analysis of weak lensing and galaxy surveys, utilizing Psi-statistic to minimize contributions from smallest physical scales and showing comparable constraining power to standard two-point galaxy clustering statistics. It demonstrates a significant decrease in bias on cosmological parameter S-8 when analyzing Psi-statistics compared to standard two-point correlation functions, highlighting the importance of moving towards new statistics less sensitive to smallest physical scales in 3 x 2pt analyses.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Robin E. Upham, Michael L. Brown, Lee Whittaker
Summary: The study shows that a Gaussian likelihood is accurate in obtaining parameter constraints from a combined tomographic power spectrum analysis in weak lensing and galaxy clustering studies. Even in the cut sky scenario, the Gaussian likelihood remains sufficient for obtaining robust parameter constraints.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
R. E. Upham, M. L. Brown, L. Whittaker, A. Amara, N. Auricchio, D. Bonino, E. Branchini, M. Brescia, J. Brinchmann, V Capobianco, C. Carbone, J. Carretero, M. Castellano, S. Cavuoti, A. Cimatti, R. Cledassou, G. Congedo, L. Conversi, Y. Copin, L. Corcione, M. Cropper, A. Da Silva, H. Degaudenzi, M. Douspis, F. Dubath, C. A. J. Duncan, X. Dupac, S. Dusini, A. Ealet, S. Farrens, S. Ferriol, P. Fosalba, M. Frailis, E. Franceschi, M. Fumana, B. Garilli, B. Gillis, C. Giocoli, F. Grupp, S. V. H. Haugan, H. Hoekstra, W. Holmes, F. Hormuth, A. Hornstrup, K. Jahnke, S. Kermiche, A. Kiessling, M. Kilbinger, T. Kitching, M. Kummel, M. Kunz, H. Kurki-Suonio, S. Ligori, P. B. Lilje, I Lloro, O. Marggraf, K. Markovic, F. Marulli, M. Meneghetti, G. Meylan, M. Moresco, L. Moscardini, E. Munari, S. M. Niemi, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, V Pettorino, S. Pires, M. Poncet, L. Popa, F. Raison, J. Rhodes, E. Rossetti, R. Saglia, B. Sartoris, P. Schneider, A. Secroun, G. Seidel, C. Sirignano, G. Sirri, L. Stanco, J-L Starck, P. Tallada-Crespi, D. Tavagnacco, A. N. Taylor, I Tereno, R. Toledo-Moreo, F. Torradeflot, L. Valenziano, Y. Wang, G. Zamorani, J. Zoubian, S. Andreon, M. Baldi, S. Camera, V. F. Cardone, G. Fabbian, G. Polenta, A. Renzi, B. Joachimi, A. Hall, A. Loureiro, E. Sellentin
Summary: An accurate covariance matrix is important for obtaining reliable cosmological results. This paper studies the covariance of pseudo-C-l estimates of cosmic shear power spectra and finds good agreement between theoretical and simulated covariance. Extreme sky cuts lead to increased off-diagonal covariance and non-Gaussian super-sample covariance.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Carolina Parroni, Edouard Tollet, Vincenzo F. Cardone, Roberto Maoli, Roberto Scaramella
Summary: This study aims to develop a new method for treating weak-lensing higher-order statistics to break the degeneracy among cosmological parameters by probing non-Gaussian properties of the shear field. By simulating lensing maps and using machine learning algorithms, a multidimensional linear regression model was found to be the most optimal for accurately measuring the majority of parameters considered in this study.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Rossana Ruggeri, Chris Blake, Joseph Derose, C. Garcia-Quintero, B. Hadzhiyska, M. Ishak, N. Jeffrey, S. Joudaki, Alex Krolewski, J. U. Lange, A. Leauthaud, A. Porredon, G. Rossi, C. Saulder, E. Xhakaj, D. Brooks, G. Dhungana, A. de la Macorra, P. Doel, S. Gontcho A. Gontcho, A. Kremin, M. Landriau, R. Miquel, C. Poppett, F. Prada, Gregory Tarle
Summary: Combining different observational probes is a promising technique for understanding the physics of the Universe. In this study, we analyze simulated data and establish a new strategy for combining high-quality cosmological imaging and spectroscopic data. By using an optimal data compression scheme, we are able to preserve all the information related to the growth of structures.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Xiangchong Li, Rachel Mandelbaum
Summary: Shear estimation bias, caused by galaxy detection and blending identification, is a known issue in current and future weak-lensing surveys. This study presents an analytical correction method that is accurate and easier to use compared to numerical shearing. By deriving the linear shear responses of pixel values and galaxy properties, we correct for biases in galaxy detection and sample selection. With the analytical covariance matrix, we also correct for noise biases in galaxy shape measurement and the detection/selection process.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
Xiangchong Li, Yin Li, Richard Massey
Summary: This study presents an improved version of the Fourier Power Function Shapelets (FPFS) shear measurement method, which includes analytic corrections for bias sources without relying on external calibration. The method achieves accurate measurement of galaxy shapes, meeting the requirements of Stage IV experiments, and is robust against faint galaxies and stellar contamination.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Patrick Simon, Stefan Hilbert
Summary: By testing two semi-analytic models with data from the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS), a study found that galaxy bias increases with scale and stellar mass, and shows color dependency. Despite reasonable agreement on relative changes with scale and galaxy properties, there is a clear conflict for the galaxy bias factor b(k) without model preference.
ASTRONOMY & ASTROPHYSICS
(2021)
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
Lee Whittaker
Summary: This study demonstrates the accurate reconstruction of shear fields and inference of cosmological parameters using only galaxy position angles, without full-ellipticity information. By extending the method to handle variable and anisotropic point spread function (PSF) convolution and variable shear fields, the study shows improvement in constraining cosmological parameters with comparable power to a basic application of IM3SHAPE.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
A. Campos, S. Samuroff, R. Mandelbaum
Summary: In this paper, an empirical approach to model selection is proposed, which balances parameter bias against model complexity. Synthetic data is used to calibrate the relationship between bias and the chi(2) difference between models, enabling the interpretation of chi(2) values obtained from real data and the selection of appropriate models. The method is applied to the problem of intrinsic alignments in cosmology, and the commonly used non-linear alignment (NLA) and tidal alignment and tidal torque (TATT) models are compared.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Max E. Lee, Tianhuan Lu, Zoltan Haiman, Jia Liu, Ken Osato
Summary: The A20-BCM is accurate at per cent level for peak counts with S/N < 4 and statistically indistinguishable from IllustrisTNG in most current and ongoing surveys. However, it is insufficient for deep future surveys covering large solid angles and underpredicts the amplitude of the highest peaks. The A20-BCM is a viable substitute for ongoing and future surveys with modest solid angles, but refinements are needed for the largest surveys.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)