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The growing field of large-scale time domain astronomy requires methods for probabilistic data analysis that are computationally tractable, even with large datasets. Gaussian Processes are a popular class of models used for this purpose…

Instrumentation and Methods for Astrophysics · Physics 2017-11-15 Daniel Foreman-Mackey , Eric Agol , Sivaram Ambikasaran , Ruth Angus

We present a rigorous and practical way of constraining the Galactic potential based on the phase-space information for many individual stars. Such an approach is needed to dynamically model the data from ongoing spectroscopic surveys of…

Astrophysics of Galaxies · Physics 2015-07-10 Yuan-Sen Ting , Hans-Walter Rix , Jo Bovy , Glenn van de Ven

The continuity equation is developed for the stellar mass content of galaxies, and exploited to derive the stellar mass function of active and quiescent galaxies over the redshift range $z\sim 0-8$. The continuity equation requires two…

Astrophysics of Galaxies · Physics 2018-05-18 A. Lapi , Claudia Mancuso , A. Bressan , L. Danese

The gravitational properties of a torus are investigated. It is shown that a torus can be formed from test particles orbiting in the gravitational field of a central mass. In this case, a toroidal distribution is achieved because of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Elena Yu. Bannikova , Victor G. Vakulik , Alexey V. Sergeev

Estimation of planetary orbital and physical parameters from light-curve data relies heavily on the accurate interpretation of Transit Timing Variations (TTV) measurements. In this letter, we review the process of TTV measurement and…

Earth and Planetary Astrophysics · Physics 2023-11-14 Yair Judkovsky , Aviv Ofir , Oded Aharonson

A method is presented for finding anisotropic distribution functions for stellar systems with known, spherically symmetric, densities, which depends only on the two classical integrals of the energy and the magnitude of the angular…

Astrophysics · Physics 2008-12-31 Zhenglu Jiang , Leonid Ossipkov

A new method for the statistical analysis of 3D point processes, based on the family of Minkowski functionals, is explained and applied to modelled galaxy distributions generated by a toy-model and cosmological simulations of the…

Astrophysics · Physics 2007-05-23 Michael Platzoeder , Thomas Buchert

Galaxy modelling is greatly simplified by assuming the existence of a global system of angle-action coordinates. Unfortunately, global angle-action coordinates do not exist because some orbits become trapped by resonances, especially where…

Astrophysics of Galaxies · Physics 2016-08-17 James Binney

Two methods of constructing 2D Toda $\tau$-functions that are generating functions for certain geometrical invariants of a combinatorial nature are related. The first involves generation of paths in the Cayley graph of the symmetric group…

Mathematical Physics · Physics 2016-11-01 Mathieu Guay-Paquet , J. Harnad

Distribution functions (DFs) for dynamically warm thin stellar disks residing in arbitrary axisymmetric potentials are presented which approximately reproduce pre-described surface-density and velocity-dispersion profiles. The functional…

Astrophysics · Physics 2009-10-31 Walter Dehnen

The two-point correlation function of the galaxy distribution is a key cosmological observable that allows us to constrain the dynamical and geometrical state of our Universe. To measure the correlation function we need to know both the…

The present-day response of a Galactic disc stellar population to a non-axisymmetric perturbation of the potential has previously been computed through perturbation theory within the phase-space coordinates of the unperturbed axisymmetric…

Astrophysics of Galaxies · Physics 2017-08-30 Giacomo Monari , Benoit Famaey , Jean-Baptiste Fouvry , James Binney

We apply for the first time a two-dimensional fitting statistic, $\tau^2$, to rotational evolution models (REMs) of stars (0.1 to 1.3 $M_{\odot}$) on the period-mass plane. The $\tau^2$ statistic simultaneously considers all cluster…

Solar and Stellar Astrophysics · Physics 2021-06-02 Angela A. Breimann , Sean P. Matt , Tim Naylor

Motivated by the search for new observables in nonperturbative quantum gravity, we consider Causal Dynamical Triangulations (CDT) in 2+1 dimensions with the spatial topology of a torus. This system is of particular interest, because one can…

High Energy Physics - Theory · Physics 2013-07-11 T. G. Budd , R. Loll

The hypergeometric distribution is a popular distribution, whose properties have been extensively investigated. Generating functions of this distribution, such as the probability-generating function, the moment-generating function, and the…

Probability · Mathematics 2024-07-31 Ken Yamamoto

The remarkably filamentary spatial distribution of young stars in the Taurus molecular cloud has significant implications for understanding low-mass star formation in relatively quiescent conditions. The large scale and regular spacing of…

Astrophysics · Physics 2008-11-26 Lee Hartmann

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

Diffusion processes are fundamental in modelling stochastic dynamics in natural sciences. Recently, simulating such processes on complicated geometries has found applications for example in biology, where toroidal data arises naturally when…

Probability · Mathematics 2019-06-25 Mathias Højgaard Jensen , Anton Mallasto , Stefan Sommer

Weak gravitational lensing requires precise measurements of galaxy shapes and therefore an accurate knowledge of the PSF model. The latter can be a source of systematics that affect the shear two-point correlation function. A key stake of…

We present a novel and efficient method for fitting dynamical models of stellar kinematic data in dwarf spheroidal galaxies (dSph). Our approach is based on Gaussian-process emulation (GPE), which is a sophisticated form of curve fitting…

Astrophysics of Galaxies · Physics 2019-04-10 Amery Gration , Mark I. Wilkinson