Results 111 to 120 of about 33,635 (203)

Sparsity covariance: a source of uncertainty when estimating correlation functions with a discrete sample of observations in the sky

The Open Journal of Astrophysics
Cosmological observables rely heavily on summary statistics such as two-point correlation functions. In many practical cases (e.g. the weak-lensing cosmic shear), those correlation functions are estimated from a finite, discrete sample of measurements ...
Pierre Fleury
doaj   +1 more source

The Peak/Dip Picture of the Cosmic Web

, 2014
The initial shear field plays a central role in the formation of large-scale structures, and in shaping the geometry, morphology, and topology of the cosmic web. We discuss a recent theoretical framework for the shear tensor, termed the `peak/dip picture'
Rossi, Graziano
core   +1 more source

Cosmic Shear with the VLT

, 2000
We report on the detection of cosmic shear on angular scales of 1.3-6.5 arcmin using 45 independent empty fields observed with the Very Large Telescope (VLT). This result confirms previous measurements obtained with the CFH Telescope at the same angular scales. We present the data analysis and the first preliminary results.
Maoli, R., Mellier, Y., van Waerbeke, L., Schneider, P., Jain, B., Erben, T., Bernardeau, F., Fort, B. Fort   +7 more
openaire   +2 more sources

Reanalysis of Stage-III cosmic shear surveys: A comprehensive study of shear diagnostic tests

The Open Journal of Astrophysics
In recent years, weak lensing shear catalogs have been released by various Stage-III weak lensing surveys including the Kilo-Degree Survey, the Dark Energy Survey, and the Hyper Suprime-Cam Subaru Strategic Program.
Jazmine Jefferson, Yuuki Omori, Chihway Chang, Shrihan Agarwal, Joe Zuntz, Marika Asgari, Marco Gatti, Benjamin Giblin, Claire-Alice Hébert, Mike Jarvis, Eske M. Pedersen, Judit Prat, Theo Schutt, Tianqing Zhang, the LSST Dark Energy Science Collaboration   +14 more
doaj   +1 more source

Analysis of two-point statistics of cosmic shear: III. Covariances of shear measures made easy

, 2007
In recent years cosmic shear, the weak gravitational lensing effect by the large-scale structure of the Universe, has proven to be one of the observational pillars on which the cosmological concordance model is founded.
B. Joachimi, Bacon, Bacon, Bardeen, Bartelmann, Bartelmann, Baumgart, Benabed, Crittenden, Feldman, Gunn, Hamilton, Hetterscheidt, Hirata, Hoekstra, Hu, Hu, Hu, Huterer, Jain, Jarvis, Kaiser, Kilbinger, Kilbinger, King, Ma, P. Schneider, Peacock, Schneider, Schneider, Schneider, Semboloni, Semboloni, Simon, Smith, Smith, Spergel, T. Eifler, Takada, van Waerbeke, Wittman   +40 more
core   +1 more source

Generation of realistic input parameters for simulating atmospheric point-spread functions at astronomical observatories

The Open Journal of Astrophysics
High-fidelity simulated astronomical images are an important tool in developing and measuring the performance of image-processing algorithms, particularly for high precision measurements of cosmic shear -- correlated distortions of images of distant ...
Claire-Alice Hébert, Joshua E. Meyers, My H. Do, Patricia R. Burchat, LSST Dark Energy Science Collaboration   +4 more
doaj   +1 more source

A New Framework for Understanding Systematic Errors in Cluster Lens Modeling. III. Deflection from Large-Scale Structure

The Astrophysical Journal
Interpreting and reconstructing distant sources that are gravitationally lensed by galaxy clusters requires accurate and precise lens models. While high-quality data sets have reduced statistical errors in such models, systematic errors remain important.
Aniruddha Madhava, Charles R. Keeton
doaj   +1 more source

Studying X-ray spectra from large-scale jets of Fanaroff–Riley type I radio galaxies: Application of shear particle acceleration

Astronomy & Astrophysics
Shear acceleration is a promising candidate mechanism for particle acceleration in extragalactic relativistic jets. For this study, we explored the application of the shear acceleration model to 17 X-ray-bright jet regions in the large-scale jets of ...
Wang Jia-Xing, He Jia-Chun, Sun Xiao-Na, Wang Jie-Shuang, Rieger Frank M., Liang Yun-Feng, Zhang Hai-Ming, Liang En-Wei   +7 more
doaj   +1 more source

Baryon-free $S_8$ tension with Stage IV cosmic shear surveys

The Open Journal of Astrophysics
Accurately modelling matter power spectrum effects at small scales, such as baryonic feedback, is essential to avoid significant bias in the estimation of cosmological parameters with cosmic shear.
Ottavia Truttero, Joe Zuntz, Alkistis Pourtsidou, Naomi Robertson   +3 more
doaj   +1 more source

The DECADE cosmic shear project III: validation of analysis pipeline using spatially inhomogeneous data

The Open Journal of Astrophysics
We present the pipeline for the cosmic shear analysis of the Dark Energy Camera All Data Everywhere (DECADE) weak lensing dataset: a catalog consisting of 107 million galaxies observed by the Dark Energy Camera (DECam) in the northern Galactic cap.
D. Anbajagane, C. Chang, N. Chicoine, L. F. Secco, C. Y. Tan, P. S. Ferguson, A. Drlica-Wagner, K. Herron, M. Adamow, R. A. Gruendl, M. R. Becker, R. Teixeira, Z. Zhang, A. Alarcon, D. Suson, A. N. Alsina, A. Amon, F. Andrade-Oliveira, J. Blazek, H. Camacho, J. A. Carballo-Bello, W. Cerny, Y. Choi, C. Doux, M. Gatti, D. Gruen, D. J. James, E. Krause, N. Kuropatkin, C. E. Martínez-Vázquez, P. Massana, S. Mau, J. McCullough, G. E. Medina, B. Mutlu-Pakdil, M. Navabi, N. E. D. Noël, A. B. Pace, A. Porredon, M. Raveri, A. H. Riley, J. D. Sakowska, S. Samuroff, D. Sanchez-Cid, D. J. Sand, L. Santana-Silva, M. Soares-Santos, G. S. Stringfellow, C. To, A. K. Vivas, M. Yamamoto, A. Zenteno, J. Zuntz   +52 more
doaj   +1 more source