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The parallel code NMAGIC is an implementation of a particle-based method to create made-to-measure models in agreement with observations of galaxies. It works by slowly correcting the particle weights of an evolving N-body system, until a…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-30 Lucia Morganti , Ortwin Gerhard

We describe a made-to-measure algorithm for constructing N-particle models of stellar systems from observational data (Chi-Squared-M2M), extending earlier ideas by Syer and Tremaine. The algorithm properly accounts for observational errors,…

Astrophysics · Physics 2008-11-26 Flavio de Lorenzi , Victor Debattista , Ortwin Gerhard , Niranjan Sambhus

Among dynamical modeling techniques, the made-to-measure (M2M) method for modeling steady-state systems is among the most flexible, allowing non-parametric distribution functions in complex gravitational potentials to be modeled efficiently…

Astrophysics of Galaxies · Physics 2017-11-28 Jo Bovy , Daisuke Kawata , Jason A. S. Hunt

We have developed the initial version of a new particle-by-particle adaptation of the made-to-measure (M2M) method, aiming to model the Galactic disc from upcoming Galactic stellar survey data. In our new particle-by-particle M2M, the…

Astrophysics of Galaxies · Physics 2015-06-11 Jason A. S. Hunt , Daisuke Kawata

We have modified our particle-by-particle adaptation of the made-to-measure (M2M) method, with the aim of modelling the Galactic disc from upcoming Galactic stellar survey data. In our new particle-by-particle M2M algorithm, PRIMAL, the…

Astrophysics of Galaxies · Physics 2015-06-15 Jason A. S. Hunt , Daisuke Kawata , Hugo Martel

Probabilistic Circuits (PCs) are a promising avenue for probabilistic modeling. They combine advantages of probabilistic graphical models (PGMs) with those of neural networks (NNs). Crucially, however, they are tractable probabilistic…

Machine Learning · Computer Science 2021-06-07 Anji Liu , Guy Van den Broeck

Diffusion models cannot enforce hard constraints, yet applications in the physical sciences demand exact satisfaction of conservation laws, boundary conditions, and observational consistency. In this work, we identify a corrector kernel…

Machine Learning · Computer Science 2026-05-14 Omer Rochman-Sharabi , Gilles Louppe

The algebraic reformulation of molecular Quantum Electrodynamics (mQED) at finite temperatures is applied to Nuclear Magnetic Resonance (NMR) in order to provide a foundation for the reconstruction of much more detailed molecular…

Quantum Physics · Physics 2020-09-25 Kolja Them

Traditional star formation subgrid models implemented in cosmological galaxy formation simulations, such as that of Springel & Hernquist (2003, hereafter SH03), employ adjustable parameters to satisfy constraints measured in the local…

(Abridged) We describe a new iterative approach for the realization of equilibrium N-body systems for given density distributions. Our method uses elements of Schwarzschild's technique and of the made-to-measure method, but is based on a…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-20 Denis Yurin , Volker Springel

Modeling interacting galaxies to reproduce observed systems is still a challenge due to the extended parameter space (among other problems). Orbit and basic galaxy parameters can be tackled by fast simulation techniques like the restricted…

Astrophysics · Physics 2009-11-13 Hanns P. Petsch , Christian Theis

We enhance the Syer & Tremaine made-to-measure (M2M) particle method of stellar dynamical modelling to model simultaneously both kinematic data and absorption line strength data thus creating a `chemo-M2M' modelling scheme. We apply the…

Astrophysics of Galaxies · Physics 2016-12-14 Richard Long

Particle MCMC is a class of algorithms that can be used to analyse state-space models. They use MCMC moves to update the parameters of the models, and particle filters to propose values for the path of the state-space model. Currently the…

Computation · Statistics 2014-12-25 Chris Nemeth , Paul Fearnhead

Algebraic multigrid (AMG) is often an effective solver for symmetric positive definite (SPD) linear systems resulting from the discretization of general elliptic PDEs, or the spatial discretization of parabolic PDEs. However, convergence…

Numerical Analysis · Mathematics 2019-09-10 Thomas A. Manteuffel , Steffen Munzenmaier , John Ruge , Ben S. Southworth

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

We reformulate the density matrix renormalization group method (DMRG) in terms of a single block, instead of the standard left and right blocks used in the construction of the superblock. This version of the DMRG, which we call the puncture…

Condensed Matter · Physics 2009-10-31 M. A. Martin-Delgado , J. Rodriguez-Laguna , G. Sierra

We have developed our original made-to-measure (M2M) algorithm, PRIMAL, with the aim of modelling the Galactic disc from upcoming Gaia data. From a Milky Way like N-body disc galaxy simulation, we have created mock Gaia data using M0III…

Astrophysics of Galaxies · Physics 2017-05-10 Jason A. S. Hunt , Daisuke Kawata

We describe an algorithm for constructing N-body realisations of equilibrium stellar systems. The algorithm complements existing orbit-based modelling techniques using linear programming or other optimization algorithms. The equilibria are…

Astrophysics · Physics 2015-06-24 D. Syer , S. Tremaine

We take a sample of 24 elliptical and lenticular galaxies previously analysed by the SAURON project using three-integral dynamical models created with Schwarzschild's method, and re-analyse them using the made-to-measure (M2M) method of…

Astrophysics of Galaxies · Physics 2015-06-03 R. J. Long , Shude Mao

While dense non-rigid structure from motion (NRSfM) has been extensively studied from the perspective of the reconstructability problem over the recent years, almost no attempts have been undertaken to bring it into the practical realm. The…

Computer Vision and Pattern Recognition · Computer Science 2020-07-01 Vladislav Golyanik , André Jonas , Didier Stricker , Christian Theobalt
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