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Related papers: Testing modified gravity with dwarf spheroidal gal…

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Ultrafaint dwarf (UFD) galaxies are dominated by dark matter, the distribution of which may be inferred from the kinematics of that galaxy's stellar population. Star-by-star observations are available for the satellite UFD galaxies of the…

Astrophysics of Galaxies · Physics 2026-02-16 Amery Gration , David D. Hendriks , Payel Das , Daniel Heber , Robert G. Izzard

We present a new analysis of the relative detectability of dark matter annihilation in the Milky Way's eight classical dwarf spheroidal satellite galaxies. Ours is similar to previous analyses in that we use Markov-Chain Monte Carlo…

High Energy Astrophysical Phenomena · Physics 2011-07-05 M. G. Walker , C. Combet , J. A. Hinton , D. Maurin , M. I. Wilkinson

We investigate the solution of Maxwell's equations in curved spacetime within the framework of Modified Gravity (MOG). We show that besides the null-geodesic treatment of photons in MOG, using Maxwell's equations and covariant coupling with…

General Relativity and Quantum Cosmology · Physics 2018-11-14 S. Rahvar , J. W. Moffat

We present a general phenomenological model for the metallicity distribution (MD) in terms of [Fe/H] for dwarf spheroidal galaxies (dSphs). These galaxies appear to have stopped accreting gas from the intergalactic medium and are fossilized…

Astrophysics of Galaxies · Physics 2015-06-04 Yong-Zhong Qian , Gerald J. Wasserburg

Scalar-Tensor-Vector Gravity (STVG), also referred as MOdified Gravity (MOG), is an alternative theory of the gravitational interaction. Its weak field approximation has been successfully used to described Solar System observations, galaxy…

General Relativity and Quantum Cosmology · Physics 2017-02-02 Federico G. Lopez Armengol , Gustavo E. Romero

The equation of motion in the generally covariant modified gravity (MOG) theory leads, for weak gravitational fields and non-relativistic motion, to a modification of Newton's gravitational acceleration law. In addition to the metric…

General Relativity and Quantum Cosmology · Physics 2019-05-24 M. A. Green , J. W. Moffat

We have completed a Monte-Carlo simulation to estimate the effect of binary star orbits on the measured velocity dispersion in dwarf spheroidal galaxies. This paper analyses previous attempts at this calculation, and explains the…

Astrophysics · Physics 2015-06-24 J. C. Hargreaves , G. Gilmore , J. D. Annan

We estimate the conventional astrophysical emission from dwarf spheroidal satellite galaxies (dSphs) of the Milky Way, focusing on millisecond pulsars (MSPs), and evaluate the potential for confusion with dark matter (DM) annihilation…

High Energy Astrophysical Phenomena · Physics 2016-11-15 Miles Winter , Gabrijela Zaharijas , Keith Bechtol , Justin Vandenbroucke

Astrophysical data analysis of the weak-field predictions support the claim that modified gravity (MOG) theories provide a self-consistent, scale-invariant, universal description of galaxy rotation curves, without the need of non-baryonic…

Astrophysics of Galaxies · Physics 2009-08-09 J. R. Brownstein

We present spectroscopic metallicities of individual stars in seven gas-rich dwarf irregular galaxies (dIrrs), and we show that dIrrs obey the same mass-metallicity relation as the dwarf spheroidal (dSph) satellites of both the Milky Way…

Astrophysics of Galaxies · Physics 2013-12-02 Evan N. Kirby , Judith G. Cohen , Puragra Guhathakurta , Lucy Cheng , James S. Bullock , Anna Gallazzi

We present a large sample of fully self-consistent hydrodynamical Nbody/Tree-SPH simulations of isolated dwarf spheroidal galaxies (dSphs). It has enabled us to identify the key physical parameters and mechanisms at the origin of the…

Astrophysics of Galaxies · Physics 2015-05-13 Y. Revaz , P. Jablonka , T. Sawala , V. Hill , B. Letarte , M. Irwin , G. Battaglia , A. Helmi , M. D. Shetrone , E. Tolstoy , K. A. Venn

Based on the observed paucity of the dwarf spheroidal (dSph) satellites of the Milky Way at small Galactocentric distances, we put forward the hypothesis that subsequent to the formation of the Milky Way and its satellites, those dSphs that…

Astrophysics · Physics 2008-11-26 R. Cowsik , Charu Ratnam , Pijushpani Bhattacharjee , Subhabrata Majumdar

We measure the three components of velocity dispersion, $\sigma_{R},\sigma_{\theta},\sigma_{\phi}$, for stars within 6 < R < 30 kpc of the Milky Way using a new radial velocity sample from the MMT telescope. We combine our measurements with…

Astrophysics of Galaxies · Physics 2015-11-11 Charles King , Warren R. Brown , Margaret J. Geller , Scott J. Kenyon

Although still under debate, observations generally suggest that dwarf spheroidal (dSph) galaxies exhibit large constant-density cores in the centers, which can hardly be explained by dissipationless cold dark matter simulations without…

Astrophysics of Galaxies · Physics 2017-04-12 Shu-Rong Chen , Hsi-Yu Schive , Tzihong Chiueh

We present the recently derived Wolf et al. (2009) mass estimator, which is applicable for spherical pressure-supported stellar systems spanning over ten orders of magnitude in luminosity, as a tool to test galaxy formation theories. We…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Joe Wolf

Wide binary stars are used to test the modified gravity called Scalar-Tensor-Vector Gravity or MOG. This theory is based on the additional gravitational degrees of freedom, the scalar field $G=G_N(1+\alpha)$, where $G_N$ is Newton's…

General Relativity and Quantum Cosmology · Physics 2024-05-31 John W. Moffat

We use a K-selected (22.5 < K_AB < 24.0) sample of dwarf galaxies (8.4 < log(M*/Msun) < 10) at 0.89<z<1.15 in the Chandra Deep Field South (CDFS) to measure their contribution to the global star-formation rate density (SFRD), as inferred…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 G. T. Davies , David Gilbank , Karl Glazebrook , Richard Bower , I. K. Baldry , Michael Balogh , G. K. T. Hau , I. H. Li , P. McCarthy , S. Savaglio

We examine the prospects for detecting gamma-rays from dark matter annihilation in the six most promising dwarf spheroidal (dSph) satellite galaxies of the Milky Way. We use recently-measured velocity dispersion profiles to provide a…

We investigate the success and problems of MOdified Newtonian Dynamics (MOND) in explaining the structural parameters and dynamics of remote Galactic globular clusters (GCs) and dwarf spheroidal (dSph) galaxies. Using the MOND value for the…

Astrophysics · Physics 2010-11-11 F. J. Sanchez-Salcedo , X. Hernandez

We present results from high-resolution N-Body/SPH simulations of rotationally supported dwarf irregular galaxies moving on bound orbits in the massive dark matter halo of the Milky Way.The dwarf models span a range in disk surface density…