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The aim of the analysis of data from the Gaia Space Observatory is to obtain kinematic parameters of the collective motion of stars in a part of our galaxy. This research is based on a statistical analysis of the motion of {$55,038,539$}…

Astrophysics of Galaxies · Physics 2025-02-18 Petr Zavada , Karel Píška

In this study, the nonlinear analysis of the sunspot index is embedded in the non-extensive statistical theory of Tsallis. The triplet of Tsallis, as well as the correlation dimension and the Lyapunov exponent spectrum were estimated for…

Chaotic Dynamics · Physics 2015-06-04 G. P. Pavlos , L. P. Karakatsanis , M. N. Xenakis

We discuss the distribution of radial velocities of galaxies belonging to the Local Group. Two independent samples of galaxies as well as several methods of reduction from the heliocentric to the galactocentric radial velocities are…

Astrophysics · Physics 2016-08-30 Wlodzimierz Godlowski , Katarzyna Bajan , Piotr Flin

In this study it is shown that the Tsallis q-extended statistical theory was found efficient to describe faithfully the space plasmas statistics in every case, from the planetic magnetospheres, to solar corona and solar dynamics, as well as…

Chaotic Dynamics · Physics 2012-03-20 G. P. Pavlos

We present a mathematical analysis of the statistical parallax method. The method yields physical insight into the maximum-likelihood determinations of the luminosity and velocity distribution and enables us to conduct a vigorous Monte…

Astrophysics · Physics 2008-02-03 Piotr Popowski , Andrew Gould

With particular attention to the recently postulated introduction of a non-extensive generalization of Boltzmann-Gibbs statistics, we study the long-term stellar dynamical evolution of self-gravitating systems on timescales much longer than…

Astrophysics · Physics 2009-11-07 Atsushi Taruya , Masa-aki Sakagami

We present multifiber echelle radial velocity results for 551 stars in the Sextans dwarf spheroidal galaxy and identify 294 stars as probable Sextans members. The projected velocity dispersion profile of the binned data remains flat to a…

Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Aims. We aim at characterizing the statistical properties of magnetic activity cycles, and studying their impact…

Solar and Stellar Astrophysics · Physics 2011-07-28 C. Lovis , X. Dumusque , N. C. Santos , F. Bouchy , M. Mayor , F. Pepe , D. Queloz , D. Ségransan , S. Udry

We analyze the internal velocity dispersions of a sample of 172 nearby galaxy clusters (z < 0.15), each of which has at least 30 available galaxy redshifts, and spans a large richness range. Cluster membership selection is based on…

We characterize empirically the radial diffusion of stars in the plane of a typical barred disk galaxy by calculating the local spatial diffusion coefficient and diffusion time-scale for bulge-disk-halo N-body self-consistent systems which…

Astrophysics of Galaxies · Physics 2015-05-30 Maura Brunetti , Cristina Chiappini , Daniel Pfenniger

We present theoretical calculations for the differential distribution of stellar orbital eccentricity for a sample of solar-neighbour halo stars. Two types of static, spherical gravitational potentials are adopted to define the eccentricity…

Astrophysics of Galaxies · Physics 2015-05-30 Kohei Hattori , Yuzuru Yoshii

Sixteen RR Lyrae variables from the QUEST survey that lie in the leading arm of the tidal stream from the Sagittarius dSph galaxy have been observed spectroscopically to measure their radial velocities and metal abundances. The systemic…

Astrophysics · Physics 2007-05-23 A. Katherina Vivas , Robert Zinn , Carme Gallart

Rotational speed is an important physical parameter of stars and knowing the distribution of stellar rotational velocities is essential for the understanding stellar evolution. However, it cannot be measured directly but the convolution of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Michel Cure , Diego F. Rial , Alejandra Christen , Julia Cassetti

Future Gaia and Legacy Survey of Space and Time data releases, together with wide area spectroscopic surveys, will deliver large samples of resolved binary stars with phase space coordinates, albeit with low-cadence. Given an eccentricity…

Solar and Stellar Astrophysics · Physics 2022-11-14 David Benisty , N. Wyn Evans , Anne-Christine Davis

Radial velocity dispersion in spheroidal and elliptical galaxies, as a function of radial distance from the center of the galaxy, has been derived from Cosmological Special Relativity. For velocity dispersions in the outer regions of…

General Physics · Physics 2009-11-13 John G. Hartnett

While stellar rotation periods $P_\mathrm{rot}$ may be measured from broadband photometry, the photometric modulation becomes harder to detect for slower rotators, which could bias measurements of the long-period tail of the…

Solar and Stellar Astrophysics · Physics 2021-12-22 Kento Masuda , Erik A. Petigura , Oliver J. Hall

Using a penalised maximum likelihood we estimate, for the first time, the velocity distribution of white dwarfs in the Solar neighbourhood. Our sample consists of 129 675 white dwarfs within 500 pc in Gaia Early Data Release 3 The white…

Solar and Stellar Astrophysics · Physics 2022-02-17 Daniel Mikkola , Paul J. McMillan , David Hobbs , John Wimarsson

Accurate determination of the local dark matter density is important for understanding the nature and distribution of dark matter in the universe. This requires that the local velocity distribution is characterised correctly. Here, we…

Astrophysics of Galaxies · Physics 2015-08-06 Alex Büdenbender , Glenn van de Ven , Laura L. Watkins

We use an improved wavelet analysis technique to reconstruct the $(U,V,W)$ velocity distribution for $\sim 250000$ stars from Gaia DR2, residing in the solar neighborhood of $200$~pc. The 2D wavelet transforms for three bivariate…

Solar and Stellar Astrophysics · Physics 2020-11-20 R. V. Baluev , V. Sh. Shaidulin , A. V. Veselova

We report the results of a statistical analysis of the space distribution of galaxies within distances about 300 Mpc using the 2MRS catalog, which contains redshifts of 43533 galaxies of the 2MASS all-sky IR survey. Because of the unique…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-26 Daniil Tekhanovich , Yurij V. Baryshev