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The extraction of object outlines has been a research topic during the last decades. In spite of advances in photogrammetry, remote sensing and computer vision, this task remains challenging due to object and data complexity. The…

Computer Vision and Pattern Recognition · Computer Science 2019-04-30 Sophie Crommelinck , Mila Koeva , Michael Ying Yang , George Vosselman

We generalize a recent model-independent form factor parameterization derived from rigorous dispersion relations to include constraints from data in the timelike region. These constraints dictate the convergence properties of the…

High Energy Physics - Phenomenology · Physics 2014-11-17 W. W. Buck , Richard F. Lebed

In large-scale image retrieval, many indexing methods have been proposed to narrow down the searching scope of retrieval. The features extracted from images usually are of high dimensions or unfixed sizes due to the existence of key points.…

Computer Vision and Pattern Recognition · Computer Science 2021-09-15 Ying Wang , Tingzhen Liu , Zepeng Bu , Yuhui Huang , Lizhong Gao , Qiao Wang

Question Answering (QA) research is a significant and challenging task in Natural Language Processing. QA aims to extract an exact answer from a relevant text snippet or a document. The motivation behind QA research is the need of user who…

Information Retrieval · Computer Science 2018-10-10 Lokesh Kumar Sharma , Namita Mittal

We present a two-dimensional (2-D) fitting algorithm (GALFIT) designed to extract structural components from galaxy images, with emphasis on closely modeling light profiles of spatially well-resolved, nearby galaxies observed with the…

Astrophysics · Physics 2011-05-05 Chien Y. Peng , Luis C. Ho , Chris D. Impey , Hans-Walter Rix

We discuss the use of symmetries for analysing the structural identifiability and observability of control systems. Special emphasis is put on the role of discrete symmetries, in contrast to the more commonly studied continuous or Lie…

This paper addresses some questions which have arisen from the use of the S\'ersic r^{1/n} law in modelling the luminosity profiles of early type galaxies. The first issue deals with the trend between the half-light radius and the…

Astrophysics · Physics 2009-11-06 Ignacio Trujillo , Alister W. Graham , Nicola Caon

Structural parameter identifiability is a property of a differential model with parameters that allows for the parameters to be determined from the model equations in the absence of noise. One of the standard approaches to assessing this…

Algebraic Geometry · Mathematics 2020-12-29 Alexey Ovchinnikov , Gleb Pogudin , Peter Thompson

Artificial neural network emulators have been demonstrated to be a very computationally efficient method to rapidly generate galaxy spectral energy distributions (SEDs), for parameter inference or otherwise. Using a highly flexible and fast…

The next generation of spectroscopic surveys will target emission-line galaxies (ELGs) to produce constraints on cosmological parameters. We study the large scale structure traced by ELGs using a combination of a semi-analytical model of…

Astrophysics of Galaxies · Physics 2021-07-14 Esteban Jimenez , Nelson Padilla , Sergio Contreras , Idit Zehavi , Carlton Baugh , Alvaro Orsi

We may attempt to encapsulate what we know about a physical system by a model structure, $S$. This collection of related models is defined by parametric relationships between system features; say observables (outputs), unobservable…

Methodology · Statistics 2021-02-16 Jason M. Whyte

Galaxy model subtraction removes the smooth light of nearby galaxies so that fainter sources (e.g., stars, star clusters, background galaxies) can be identified and measured. Traditional approaches (isophotal or parametric fitting) are…

Instrumentation and Methods for Astrophysics · Physics 2025-10-07 Rongrong Liu , Eric W. Peng , Kaixiang Wang , Laura Ferrarese , Patrick Côté

We study the impact of photometric signal to noise on the accuracy of derived structural parameters of unresolved star clusters using MCMC model fitting techniques. Star cluster images were simulated as a smooth surface brightness…

Astrophysics of Galaxies · Physics 2018-03-14 D. Narbutis , A. Bridžius , D. Semionov

I outline a quantitative method for characterizing galaxies both by photometric `form' and indices of spectral-type, applicable to both nearby and distant galaxies. Such a characterization provides insight on galaxy evolution because there…

Astrophysics · Physics 2009-10-31 Matthew A. Bershady

In the standard (classic) approach, galaxy clustering measurements from spectroscopic surveys are compressed into baryon acoustic oscillations and redshift space distortions measurements, which in turn can be compared to cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-28 Samuel Brieden , Héctor Gil-Marín , Licia Verde

Massive early-type galaxies have undergone dramatic structural evolution over the last 10 Gyr. A companion paper shows that nearby elliptical galaxies with M*>1.3x10^{11} M_sun generically contain three photometric subcomponents: a compact…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-23 Song Huang , Luis C. Ho , Chien Y. Peng , Zhao-Yu Li , Aaron J. Barth

Galaxy lenses are frequently modeled as an elliptical mass distribution with external shear and isothermal spheres to account for secondary and line-of-sight galaxies. There is statistical evidence that some fraction of observed quads are…

Astrophysics of Galaxies · Physics 2021-04-14 Matthew R. Gomer , Liliya L. R. Williams

Galaxy morphology encodes key information about formation and evolution. Large imaging surveys require automated, reproducible methods beyond visual inspection. Non--parametric indices provide an useful framework, but their performance must…

Globular clusters (GCs) play an important role in the formation and evolution of the Milky Way. New candidates are continuously found, particularly in the high-extinction low-latitude regions of the bulge, although their existence and…

Astrophysics of Galaxies · Physics 2022-10-12 Dongwook Lim , Andreas J. Koch-Hansen , Sang-Hyun Chun , Seungsoo Hong , Young-Wook Lee

In recent years, the availability of large, complete cluster samples has enabled numerous cosmological parameter inference analyses using cluster number counts. These have provided constraints on the cosmic matter density $\Omega_m$ and the…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-23 P. S. Corasaniti , M. Sereno , S. Ettori