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A simple numerical scheme is presented for the construction of three-integral phase-space distribution functions for oblate galaxy models with a gravitational potential of St\"{a}ckel form, and an arbitrary axisymmetric luminous density…

Astrophysics · Physics 2015-06-24 F. H. A. Robijn , P. T. de Zeeuw

A general method is presented for constructing distribution functions for flat systems whose surface density and Toomre's Q number profile is given. The purpose of these functions is to provide plausible galactic models and assess their…

Astrophysics · Physics 2007-05-23 C. Pichon , D. Lynden-Bell

We investigate the structure of galaxies formed in a suite of high-resolution cosmological simulations. Consistent with observations of high-redshift galaxies, our simulated galaxies show irregular, prolate shapes, which are dominated by…

Astrophysics of Galaxies · Physics 2022-08-16 Xi Meng , Oleg Y. Gnedin , Hui Li

Many data-driven decision problems are formulated using a nominal distribution estimated from historical data, while performance is ultimately determined by a deployment distribution that may be shifted, context-dependent, partially…

Machine Learning · Computer Science 2026-04-07 Xiuyuan Cheng , Yunqin Zhu , Yao Xie

Modeling galaxy formation in a cosmological context presents one of the greatest challenges in astrophysics today, due to the vast range of scales and numerous physical processes involved. Here we review the current status of models that…

Astrophysics of Galaxies · Physics 2015-09-23 Rachel S. Somerville , Romeel Davé

We investigate how accurately phase space distribution functions (DFs) in galactic models can be reconstructed by a made-to-measure (M2M) method, which constructs $N$-particle models of stellar systems from photometric and various kinematic…

Astrophysics of Galaxies · Physics 2016-08-24 Hiromichi Tagawa , Naoteru Gouda , Taihei Yano , Takuji Hara

The construction of valid and flexible cross-covariance functions is a fundamental task for modeling multivariate space-time data arising from climatological and oceanographical phenomena. Indeed, a suitable specification of the covariance…

Statistics Theory · Mathematics 2017-11-23 Alfredo Alegría , Emilio Porcu , Reinhard Furrer , Jorge Mateu

Diffusion models have recently emerged as a powerful framework for generative modeling. They consist of a forward process that perturbs input data with Gaussian white noise and a reverse process that learns a score function to generate…

The only way to map the Galaxy's gravitational potential $\Phi({\bf x})$ and the distribution of matter that produces it is by modelling the dynamics of stars and gas. Observations of the kinematics of gas provide key information about…

Astrophysics · Physics 2007-05-23 Walter Dehnen , James Binney

A method for determining the orbital parameters of interacting pairs of galaxies is presented and evaluated using artificial data. The method consists of a genetic algorithm which can search efficiently through the very large space of…

Astrophysics · Physics 2009-10-30 M. Wahde

Intrinsic galaxy alignments yield an important contribution to the observed statistics of galaxy shapes. The general bias expansion for galaxy sizes and shapes in three dimensions has been recently described by Vlah, Chisari \& Schmidt…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-02 Zvonimir Vlah , Nora Elisa Chisari , Fabian Schmidt

In this paper, we attempt to explore the landscape of two-dimensional conformal field theories (2d CFTs) by efficiently searching for numerical solutions to the modular bootstrap equation using machine-learning-style optimization. The torus…

High Energy Physics - Theory · Physics 2026-05-05 Nathan Benjamin , A. Liam Fitzpatrick , Wei Li , Jesse Thaler

During a tracking mode observation, every telescope with an alt-azimuthal mount shows a rotation in the field of view (FoV) due to the diurnal motion of the Earth. The angular extension of the rotation depends mainly on the time length of…

Instrumentation and Methods for Astrophysics · Physics 2022-09-21 Simone Iovenitti

Conformal field theory and its axiomatisation in terms of vertex operator algebras or chiral algebras are most commonly considered on the Riemann sphere. However, an important constraint in physics and an interesting source of mathematics…

Quantum Algebra · Mathematics 2026-01-29 Matthew Krauel , Jamal Noel Shafiq , Simon Wood

Modeling dependencies between random variables independently from their marginals is fundamental in applications ranging from finance to (structural) biology. In this work, we undertake this problem using circula to model data living on the…

Applications · Statistics 2026-05-14 Guillaume Carrière , Alix Lhéritier , Frédéric Cazals

Causal Dynamical Triangulations is a non-perturbative quantum gravity model, defined with a lattice cut-off. The model can be viewed as defined with a proper time but with no reference to any three-dimensional spatial background geometry.…

High Energy Physics - Theory · Physics 2019-06-26 Jan Ambjørn , Zbigniew Drogosz , Jakub Gizbert-Studnicki , Andrzej Görlich , Jerzy Jurkiewicz

Angular measurements are often modeled as circular random variables, where there are natural circular analogues of moments, including correlation. Because a product of circles is a torus, a d-dimensional vector of circular random variables…

Methodology · Statistics 2019-10-25 Natalie Klein , Josue Orellana , Scott Brincat , Earl K. Miller , Robert E. Kass

The Gaussian function (GF) is widely used to explain the behavior or statistical distribution of many natural phenomena as well as industrial processes in different disciplines of engineering and applied science. For example, the GF can be…

Signal Processing · Electrical Eng. & Systems 2020-01-08 Ibrahim Al-Nahhal , Octavia A. Dobre , Ertugrul Basar , Cecilia Moloney , Salama Ikki

The behavior of a family of dissipative dynamical systems representing transformations of two-dimensional torus is studied on a discrete lattice and compared with that of conservative hyperbolic automorphisms of the torus. Applying…

Computational Physics · Physics 2011-06-21 L. Yu. Barash