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Related papers: Simple Distribution Functions for Stellar Disks

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We investigate the structure of our Galaxy's young stellar disc by fitting the distribution functions (DFs) of a new family to five-dimensional Gaia data for a sample of $47\,000$ OB stars. Tests of the fitting procedure show that the young…

Astrophysics of Galaxies · Physics 2022-07-20 Chengdong Li , James Binney

We explored a method to reconstruct the distribution function of the Galactic thick disc within the action space where nearby thick-disc stars are distributed. By applying this method to 127 chemically-selected thick-disc stars in the Solar…

Astrophysics of Galaxies · Physics 2015-09-30 Kohei Hattori , Gerard Gilmore

The stellar obliquity of a planetary system is often used to help constrain the system's formation and evolution. One of the mechanisms to reorient the stellar spin involves a secular resonance crossing due to the dissipation of the…

Earth and Planetary Astrophysics · Physics 2025-09-16 Yubo Su , Dong Lai

We present a new, simple, fast algorithm to numerically evolve disks of inelastically colliding particles surrounding a central star. Our algorithm adds negligible computational cost to the fastest existing collisionless N-body codes, and…

Astrophysics · Physics 2008-11-26 Yoram Lithwick , Eugene Chiang

We provide new constraints on the dark matter halo density profile of Milky Way (MW) dwarf spheroidal galaxies (dSphs) using the phase-space distribution function (DF) method. After assessing the systematics of the approach against mock…

Astrophysics of Galaxies · Physics 2024-05-31 Kevin E. Andrade , Manoj Kaplinghat , Mauro Valli

We present new tools to establish axisymmetric equilibrium models of the Milky Way. The models we wish to establish are pairs (V,F) where V is the gravitational potential generated by the whole mass distribution including the dark matter,…

Astrophysics · Physics 2015-06-24 B. Famaey , H. Dejonghe

Resolved surveys of the Milky Way's stellar halo can obtain all 6 phase space coordinates of tens of thousands of individual stars, making it possible to compute their 3-dimensional orbits. Spectral analysis of large numbers of halo orbits…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Monica Valluri

We present a series of 2-d ($r,\phi$) hydrodynamic simulations of marginally self gravitating disks around protostars using an SPH code. We implement simple dynamical heating and we cool each location as a black body, using a photosphere…

Astrophysics · Physics 2011-02-11 Andrew F. Nelson , Willy Benz , Tamara Ruzmaikina

Density functional theory (DFT) offers a desirable balance between quantitative accuracy and computational efficiency in practical many-electron calculations. Its central component, the exchange-correlation energy functional, has been…

We derive expressions for the photophoretic force on opaque spherical particles in a dilute gas in the optically thick regime where the radiation field is in local thermal equilibrium. Under those conditions, the radiation field has a…

Earth and Planetary Astrophysics · Physics 2015-10-14 Colin P. McNally , Alexander Hubbard

A new class of models of stellar discs is introduced and used to build a self-consistent model of our Galaxy. The model is defined by the parameters that specify the action-based distribution functions (DFs) f(J) of four stellar discs…

Astrophysics of Galaxies · Physics 2023-01-25 James Binney , Eugene Vasiliev

We study the population of galactic disks expected in current hierarchical clustering models for structure formation. A rotationally supported disk with exponential surface density profile is assumed to form with a mass and angular momentum…

Astrophysics · Physics 2009-10-30 H. J. Mo , Shude Mao , Simon D. M. White

In this paper we introduce the concept of Direct Statistical Simulation (DSS) for astrophysical flows. This technique may be appropriate for problems in astrophysical fluids where the instantaneous dynamics of the flows are of secondary…

Solar and Stellar Astrophysics · Physics 2011-01-17 S. M. Tobias , K. Dagon , J. B. Marston

Simulating thin and extended galactic disks has long been a challenge in computational astrophysics. We introduce the NIHAO-UHD suite of cosmological hydrodynamical simulations of Milky Way mass galaxies and study stellar disk properties…

Astrophysics of Galaxies · Physics 2020-01-08 Tobias Buck , Aura Obreja , Andrea V. Macciò , Ivan Minchev , Aaron A. Dutton , Jeremiah P. Ostriker

We present a scenario for the formation of disks which explains not only the properties of normal galaxies, but the properties of the population of low surface brightness galaxies (LSBs) as well. We use a gravitationally self-consistent…

Astrophysics · Physics 2009-10-28 J. J. Dalcanton , D. N. Spergel , F J Summers

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

Angle/action based distribution function (DF) models can be optimised based on how well they reproduce observations thus revealing the current matter distribution in the Milky Way. Gaia data combined with data from other surveys, e.g. the…

Astrophysics of Galaxies · Physics 2018-06-13 David R Cole , James Binney

The properties and star formation processes in the far-outer disks of nearby spiral and dwarf irregular galaxies are reviewed. The origin and structure of the generally exponential profiles in stellar disks is considered to result from…

Astrophysics of Galaxies · Physics 2017-08-02 Bruce G. Elmegreen , Deidre A. Hunter

Denoising Diffusion Probabilistic Models (DDPMs) provide the foundation for the recent breakthroughs in generative modeling. Their Markovian structure makes it difficult to define DDPMs with distributions other than Gaussian or discrete. In…

This paper shows how a self-consistent dynamical model can be obtained by fitting the gravitational potential of the Milky Way to the stellar kinematics and densities from Gaia data. Using the Besancon Galaxy Model we derive a potential and…

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