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Characterization of the morphology of strongly lensed galaxies is challenging because images of such galaxies are typically highly distorted. Lens modeling and source plane reconstruction is one approach that can provide reasonably…

Astrophysics of Galaxies · Physics 2016-12-14 Michael K. Florian , Nan Li , Michael D. Gladders

The sample of cosmological strong lensing systems has been steadily growing in recent years and with the advent of the next generation of space-based survey telescopes, the sample will reach into the thousands. The accuracy of strong lens…

Astrophysics of Galaxies · Physics 2016-01-20 Michael K. Florian , Michael D. Gladders , Nan Li , Keren Sharon

In this paper we present a new statistic for quantifying galaxy morphology based on measurements of the Gini coefficient of galaxy light distributions. This statistic is easy to measure and is commonly used in econometrics to measure how…

Astrophysics · Physics 2009-11-07 Roberto Abraham , Sidney van den Bergh , Preethi Nair

We present two new non-parametric methods for quantifying galaxy morphology: the relative distribution of the galaxy pixel flux values (the Gini coefficient or G) and the second-order moment of the brightest 20% of the galaxy's flux (M20).…

Astrophysics · Physics 2010-04-06 Jennifer M. Lotz , Joel Primack , Piero Madau

In recent years multi-wavelength observations have shown the presence of substructures related to merging events in a high fraction of galaxy clusters. Clusters can be roughly grouped into two categories -- relaxed and non-relaxed -- and a…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-11 Viral Parekh , Kurt van der Heyden , Chiara Ferrari , Garry Angus , Benne Holwerda

The majority of galaxy mergers are expected to be minor mergers. The observational signatures of minor mergers are not well understood, thus there exist few constraints on the minor merger rate. This paper seeks to address this gap in our…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Jennifer M. Lotz , Patrik Jonsson , T. J. Cox , Joel R. Primack

[abridged] New near-infrared surveys, using the HST, offer an unprecedented opportunity to study rest-frame optical galaxy morphologies at z>1 and to calibrate automated morphological parameters that will play a key role in classifying…

We investigate the effect of observational constraints such as signal-to-noise, resolution and column density level on the HI morphological asymmetry ($\mathrm{A}_\mathrm{mod}$) and the effect of noise on the HI global profile…

Astrophysics of Galaxies · Physics 2022-06-08 P. V. Bilimogga , K. A. Oman , M. A. W. Verheijen , J. M. van der Hulst

The morphology of galaxies can be quantified to some degree using a set of scale-invariant parameters. Concentration (C), Asymmetry (A), Smoothness (S), the Gini index (G), relative contribution of the brightest pixels to the second order…

The distribution of errors is a central object in the assesment and benchmarking of computational chemistry methods. The popular and often blind use of the mean unsigned error as a benchmarking statistic leads to ignore distributions…

Chemical Physics · Physics 2021-02-19 Pascal Pernot , Andreas Savin

Identifying statistical dependence between the features and the label is a fundamental problem in supervised learning. This paper presents a framework for estimating dependence between numerical features and a categorical label using…

Machine Learning · Computer Science 2021-10-01 Silu Zhang , Xin Dang , Dao Nguyen , Dawn Wilkins , Yixin Chen

Non-parametric morphology measures are a powerful tool for identifying galaxy mergers at low redshifts. We employ cosmological zoom simulations using Gizmo with the Mufasa feedback scheme, post-processed using 3D dust radiative transfer…

Astrophysics of Galaxies · Physics 2018-03-08 Matthew W. Abruzzo , Desika Narayanan , Romeel Davé , Robert Thompson

We study the optical morphology of galaxies in a large-scale hydrodynamic cosmological simulation, the EAGLE simulation. Galaxy morphologies were characterized using non-parametric statistics (Gini, $M_{20}$, Concentration and Asymmetry)…

Astrophysics of Galaxies · Physics 2020-01-08 Lucas A. Bignone , Susana E. Pedrosa , James W. Trayford , Patricia B. Tissera , Leonardo J. Pellizza

The presence of Active Galaxy Nuclei (AGN) can affect the morphological classification of galaxies. This work aims to determine how the contribution of AGN affects the most used morphological parameters down to the redshift of z~2 in…

Gas-rich galaxy mergers are more easily identified by their disturbed morphologies than mergers with less gas. Because the typical gas fraction of galaxy mergers is expected to increase with redshift, the under-counting of low gas-fraction…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Jennifer M. Lotz , Patrik Jonsson , T. J. Cox , Joel R. Primack

Galaxy evolution is driven to a large extent by interactions and mergers with other galaxies and the gas in galaxies is extremely sensitive to the interactions. One method to measure such interactions uses the quantified morphology of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 B. W. Holwerda , N. Pirzkal , W. J. G. de Blok , A. Bouchard , S-L. Blyth , K. J. van der Heyden , E. C. Elson

The global 21 cm HI emission-line profile of a galaxy encodes valuable information on the spatial distribution and kinematics of the neutral atomic gas. Galaxy interactions significantly influence the HI disk and imprint observable features…

Astrophysics of Galaxies · Physics 2022-04-20 Pei Zuo , Luis C. Ho , Jing Wang , Niankun Yu , Jinyi Shangguan

The two interferometric LIGO gravitational-wave observatories provide the most sensitive data to date to study the gravitational-wave Universe. As part of a global network, they have just completed their third observing run in which they…

General Relativity and Quantum Cosmology · Physics 2022-08-24 Gregory Ashton , Sarah Thiele , Yannick Lecoeuche , Jess McIver , Laura K Nuttall

The Gini index does not give a strictly consistent scoring rule in general. Therefore, maximizing the Gini index may lead to wrong decisions. The main issue is that the Gini index is a rank-based score that is not calibration-sensitive. We…

Machine Learning · Computer Science 2022-08-11 Mario V. Wüthrich

We investigate the time evolution of non-parametric morphological quantities and their relationship to major mergers between $4\geq z \geq 2$ in high-resolution cosmological zoom simulations of disk galaxies that implement kinetic wind…

Astrophysics of Galaxies · Physics 2015-08-11 Robert Thompson , Romeel Davé , Shuiyao Huang , Neal Katz
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