Concept

Galaxie à disque

Publications associées (40)

ASTErIsM: application of topometric clustering algorithms in automatic galaxy detection and classification

Jean-Paul Richard Kneib, Frédéric Courbin, Danuta Janina Paraficz

We present a study on galaxy detection and shape classification using topometric clustering algorithms. We first use the DBSCAN algorithm to extract, from CCD frames, groups of adjacent pixels with significant fluxes and we then apply the DENCLUE algorithm ...

Oxford Univ Press2016

GREAT3 results - I. Systematic errors in shear estimation and the impact of real galaxy morphology

Frédéric Courbin, Jean-Luc Starck, Thibault Adrien Kuntzer, Malte Tewes, Huanyuan Shan, Marc Gentile, Guldariya Nurbaeva, Jun Zhang

We present first results from the third GRavitational lEnsing Accuracy Testing (GREAT3) challenge, the third in a sequence of challenges for testing methods of inferring weak gravitational lensing shear distortions from simulated galaxy images. GREAT3 was ...

Oxford University Press2015

Galaxy Alignments: Observations and Impact on Cosmology

Anaïs Marie Rassat

Galaxy shapes are not randomly oriented, rather they are statistically aligned in a way that can depend on formation environment, history and galaxy type. Studying the alignment of galaxies can therefore deliver important information about the physics of g ...

Springer2015

The Smith Cloud and its dark matter halo: survival of a Galactic disc passage

Matthew Luke Nichols

Under conservative assumptions about the Galaxy, the derived velocity of the Smith Cloud indicates that it will have undergone at least one passage of the Galactic disc. Using hydrodynamic simulations, we examine the present-day structure of the Smith Clou ...

Wiley-Blackwell2014

Understanding The Unique Assembly History Of Central Group Galaxies

Jean-Paul Richard Kneib

Central galaxies (CGs) in massive halos live in unique environments with formation histories closely linked to that of the host halo. In local clusters, they have larger sizes (R-e) and lower velocity dispersions (sigma) at fixed stellar mass M-*, and much ...

American Astronomical Society2014

First galaxy-galaxy lensing measurement of satellite halo mass in the CFHT Stripe-82 Survey

Jean-Paul Richard Kneib, Huanyuan Shan

We select satellite galaxies from the galaxy group catalogue constructed with the Sloan Digital Sky Survey spectroscopic galaxies and measure the tangential shear around these galaxies with the source catalogue extracted from the Canada-France-Hawaii Teles ...

Wiley-Blackwell2014

IceCube search for dark matter annihilation in nearby galaxies and galaxy clusters

Matthias Wolf, Shirit Cohen, Sofia Vallecorsa, Mathieu Ribordy, Xiaoxia Bai

We present the results of a first search for self-annihilating dark matter in nearby galaxies and galaxy clusters using a sample of high-energy neutrinos acquired in 339.8 days of live time during 2009/10 with the IceCube neutrino observatory in its 59-str ...

Amer Physical Soc2013

Quantifying the faint structure of galaxies: the late-type spiral NGC 2403

Pascale Jablonka

Ground-based surveys have mapped the stellar outskirts of Local Group disc galaxies in unprecedented detail, but extending this work to other galaxies is necessary in order to overcome stochastic variations in evolutionary history and provide more stringen ...

Blackwell Publishing Ltd, Oxford2012

Image analysis for cosmology: results from the GREAT10 Galaxy Challenge

Frédéric Courbin, Malte Tewes, Marc Gentile, Nicolas Cantale, Guldariya Nurbaeva, Richard Massey

In this paper, we present results from the weak-lensing shape measurement GRavitational lEnsing Accuracy Testing 2010 (GREAT10) Galaxy Challenge. This marks an order of magnitude step change in the level of scrutiny employed in weak-lensing shape measureme ...

Blackwell Publishing Ltd, Oxford2012

A very extended molecular web around NGC 1275

Yves Revaz

We present the first detection of CO emission lines in the Ha filaments at distances as far as 50 kpc from the centre of the galaxy NGC 1275. This gas is probably dense (>= 10(3) cm(-3)). However, it is not possible to accurately determine the density and ...

2011

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