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Accurate redshift calibration is required to obtain unbiased cosmological information from large-scale galaxy surveys. In a forward modelling approach, the redshift distribution n(z) of a galaxy sample is measured using a parametric galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-13 Beatrice Moser , Tomasz Kacprzak , Silvan Fischbacher , Alexandre Refregier , Dominic Grimm , Luca Tortorelli

Many of the cosmological tests to be performed by planned dark energy experiments will require extremely well-characterized photometric redshift measurements. Current estimates are that the true mean redshift of the objects in each photo-z…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-22 Daniel J. Matthews , Jeffrey A. Newman

Affinity propagation clustering (AP) has two limitations: it is hard to know what value of parameter 'preference' can yield an optimal clustering solution, and oscillations cannot be eliminated automatically if occur. The adaptive AP method…

Artificial Intelligence · Computer Science 2008-05-09 Kaijun Wang , Junying Zhang , Dan Li , Xinna Zhang , Tao Guo

The thermal Sunyaev-Zel'dovich (tSZ) effect is one of the primary tools for finding and characterizing galaxy clusters. Several ground-based experiments are either underway or are being planned for mapping wide areas of the sky at $\sim…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-24 Nikhel Gupta , Cristiano Porciani , Kaustuv Basu

We introduce a novel extension of the volume-averaged correlation function (VACF) framework by replacing the traditional spherical smoothing kernels with anisotropic, ellipsoidal windows. This generalized approach enables the study of…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-03 Paweł Drozda , Wojciech A. Hellwing , Maciej Bilicki

Current measurements of the weak lensing signal induced by large scale structure provide useful constraints on a range of cosmological parameters. However, the ultimate succes of this technique depends on the accuracy with which one can…

Astrophysics · Physics 2009-11-07 Henk Hoekstra

The current methods available to estimate gravitational shear from astronomical images of galaxies introduce systematic errors which can affect the accuracy of weak lensing cosmological constraints. We study the impact of KSB shape…

We reconsider the Alcock-Paczynski effect on 21cm fluctuations from high redshift, focusing on the 21cm power spectrum. We show that at each accessible redshift both the angular diameter distance and the Hubble constant can be determined…

Astrophysics · Physics 2009-11-11 Rennan Barkana

Cosmological galaxy surveys aim at mapping the largest volumes to test models with techniques such as cluster abundance, cosmic shear correlations or baryon acoustic oscillations (BAO), which are designed to be independent of galaxy bias.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 E. Gaztanaga , M. Eriksen , M. Crocce , F. Castander , P. Fosalba , P. Marti , R. Miquel , A. Cabre

Ptychography in a reflection geometry shows great promise for non-destructive imaging of 3-dimensional nanostructures at the surface of a thick substrate. A major challenge to obtain high quality reflection-ptychographic images under…

The future 21 cm intensity mapping observations constitute a promising way to trace the matter distribution of the Universe and probe cosmology. Here we assess its capability for cosmological constraints using as a case study the BINGO…

The next generation of surveys will greatly improve our knowledge of cosmological gravity. In this paper we focus on how Stage IV photometric redshift surveys, including weak lensing and multiple tracers of the matter distribution and radio…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-18 David Alonso , Emilio Bellini , Pedro G. Ferreira , Miguel Zumalacarregui

Galaxy redshift surveys are subject to incompleteness and inhomogeneous sampling due to the various constraints inherent to spectroscopic observations. This can introduce systematic errors on the summary statistics of interest, which need…

A trustworthy estimate of the redshift distribution $n(z)$ is crucial for using weak gravitational lensing and large-scale structure of galaxy catalogs to study cosmology. Spectroscopic redshifts for the dim and numerous galaxies of…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-27 Alex I. Malz , David W. Hogg

Galaxy cross-correlations with high-fidelity redshift samples hold the potential to precisely calibrate systematic photometric redshift uncertainties arising from the unavailability of complete and representative training and validation…

Building on the first paper in this series (Duncan et al. 2018), we present a study investigating the performance of Gaussian process photometric redshift (photo-z) estimates for galaxies and active galactic nuclei detected in deep radio…

Astrophysics of Galaxies · Physics 2018-05-24 Kenneth J Duncan , Matt J. Jarvis , Michael J. I. Brown , Huub J. A. Rottgering

In the modern galaxy surveys photometric redshifts play a central role in a broad range of studies, from gravitational lensing and dark matter distribution to galaxy evolution. Using a dataset of about 25,000 galaxies from the second data…

Instrumentation and Methods for Astrophysics · Physics 2017-06-14 Stefano Cavuoti , Crescenzo Tortora , Massimo Brescia , Giuseppe Longo , Mario Radovich , Nicola R. Napolitano , Valeria Amaro , Civita Vellucci

We develop a cosmological parameter estimation code for (tomographic) angular power spectra analyses of galaxy number counts, for which we include, for the first time, redshift-space distortions (RSD) in the Limber approximation. This…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-15 Konstantinos Tanidis , Stefano Camera

We study the potential of weak lensing surveys to detect clusters of galaxies, using a fast Particle Mesh cosmological N-body simulation algorithm specifically tailored to investigate the statistics of these mass-selected clusters. In…

Astrophysics · Physics 2009-11-10 Joseph F. Hennawi , David N. Spergel

X-ray Computed Tomography (CT) reconstruction from a sparse number of views is a useful way to reduce either the radiation dose or the acquisition time, for example in fixed-gantry CT systems, however this results in an ill-posed inverse…

Data Structures and Algorithms · Computer Science 2020-11-04 Alessandro Perelli , Michael Lexa , Ali Can , Mike E. Davies
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