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I describe a general formalism for galaxy biasing (Dekel & Lahav 1998) and its application to measurements of beta (=Omega^0.6/b), e.g. via direct comparisons of light and mass and via redshift distortions. The linear and deterministic…

Astrophysics · Physics 2007-05-23 Avishai Dekel

The Australian Square Kilometer Array Pathfinder (ASKAP) will revolutionise our knowledge of gas-rich galaxies in the Universe. Here we present predictions for two proposed extragalactic ASKAP neutral hydrogen (HI) emission-line surveys,…

We present a non-parametric method to measure inhomogeneities in the intracluster medium (ICM) from X-ray observations of galaxy clusters. Analysing mock Chandra X-ray observations of simulated clusters, we show that our new method enables…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Andrea Morandi , Daisuke Nagai , Wei Cui

We utilise mock catalogues from high-accuracy cosmological $N$-body simulations to quantify shifts in the recovery of the acoustic scale that could potentially result from galaxy clustering bias. The relationship between galaxies and dark…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-30 Duan Yutong , Daniel Eisenstein

Statistical weak lensing by large-scale structure -- cosmic shear -- is a promising cosmological tool, which has motivated the design of several large upcoming surveys. Here, we present a measurement of cosmic shear using coadded Sloan…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-15 Eric M. Huff , Tim Eifler , Christopher M. Hirata , Rachel Mandelbaum , David Schlegel , Uros Seljak

We describe an improved, practical method for constructing galaxy models that match an arbitrary set of observational constraints, without prior assumptions about the phase-space distribution function (DF). Our method is an extension of…

Astrophysics · Physics 2009-10-31 Nicolas Cretton , P. Tim de Zeeuw , Roeland P. van der Marel , Hans-Walter Rix

Tests of cosmological models via measurements of galaxy correlations will require increasing modeling accuracy, given the high precision of measurements promised by forthcoming galaxy surveys. In this work we investigate the biases…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-06 Francesco Spezzati , Alvise Raccanelli

We present observational evidence of the impact of triaxiality on radial profiles that extend to 40 Mpc from galaxy cluster centres in optical measurements. We perform a stacked profile analysis from a sample of thousands of nearly relaxed…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-05 Shenming Fu , Yuanyuan Zhang , Camille Avestruz , Ruben Coronel

We present a novel Bayesian method, referred to as Blobby3D, to infer gas kinematics that mitigates the effects of beam smearing for observations using Integral Field Spectroscopy (IFS). The method is robust for regularly rotating galaxies…

We consider the problem of detecting a rectangle of activation in a grid of sensors in d-dimensions with noisy measurements. This has applications to massive surveillance projects and anomaly detection in large datasets in which one detects…

Statistics Theory · Mathematics 2014-09-26 James Sharpnack , Ery Arias-Castro

Large-scale structure surveys can be used to measure the dipole in the cosmic microwave background (CMB), in the luminosity distances inferred from type-Ia supernova observations, and in the spatial distribution of galaxies and quasars. The…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-08 Jaiyul Yoo , Matteo Magi , Dragan Huterer

We use information entropy to analyze the anisotropy in the mock galaxy catalogues from dark matter distribution and simulated biased galaxy distributions from $\Lambda$CDM N-body simulation. We show that one can recover the linear bias…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-05 Biswajit Pandey

Exploiting the full statistical power of future cosmic shear surveys will necessitate improvements to the accuracy with which the gravitational lensing signal is measured. We present a framework for calibrating shear with image simulations…

Accurate measurement of galaxy structures is a prerequisite for quantitative investigation of galaxy properties or evolution. Yet, the impact of galaxy inclination and dust on commonly used metrics of galaxy structure is poorly quantified.…

Astrophysics of Galaxies · Physics 2017-03-23 Brian Devour , Eric Bell

Axisymmetric density distributions are constructed which are invisible when viewed from a range of inclination angles $i$. By adding such distributions to a model galaxy, it can be made either disky or boxy without in any way affecting its…

Astrophysics · Physics 2015-06-24 Ortwin Gerhard , James Binney

We investigate the diversity in the sizes and average surface densities of the neutral atomic hydrogen (HI) gas discs in ~280 nearby galaxies detected by the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). We combine the…

Homogeneity is a crucial, but poorly tested, assumption in cosmology. We introduce a new approach which allows us to place limits on the presence of localized structures within essentially our entire observable volume, using cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-15 James. P. Zibin , Adam Moss

Stage IV cosmological surveys will map the universe with unprecedented precision, reducing statistical uncertainties to levels where unmodelled systematics can significantly bias inference. In particular, photometric redshift (photo-z)…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-11 Carolyn McDonald Mill , C. Danielle Leonard , Markus Michael Rau , Cora Uhlemann , Shahab Joudaki

We present a new method of utilizing the color and asymmetry values for galaxies in the Hubble Deep Field to determine both their morphological features and physical parameters. By using a color-asymmetry diagram, we show that various types…

Astrophysics · Physics 2009-10-31 Christopher J. Conselice , Matthew A. Bershady

We use automated surface photometry and pattern classification techniques to morphologically classify galaxies. The two-dimensional light distribution of a galaxy is reconstructed using Fourier series fits to azimuthal profiles computed in…

Astrophysics · Physics 2009-11-07 S. C. Odewahn , S. H. Cohen , R. A. Windhorst , N. S. Philip