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We study r-mode instability of rotating compact objects composed of asymmetric and self-interacting Fermionic dark matter (dark stars). It is argued that the instability limit the angular frequency of the stars less than half of the…

High Energy Astrophysical Phenomena · Physics 2020-11-17 Shin'ichirou Yoshida

Assuming that Dark Matter is dominated by WIMPs, it accretes by gravitational attraction and scattering over baryonic material and annihilates inside celestial objects, giving rise to a "Dark Luminosity" which may potentially affect the…

Astrophysics · Physics 2010-11-11 Fabio Iocco

A neutron star harbors of order $10^{56}$ electrons in its core, and almost the same number of muons, with muon decay prohibited by Pauli blocking. However, as macroscopic properties of the star such as its mass, rotational velocity, or…

High Energy Astrophysical Phenomena · Physics 2023-12-15 Joachim Kopp , Toby Opferkuch

The effects of dark matter (DM) on the curvatures of the neutron star (NS) are examined by using the stiff and soft relativistic mean-field equation of states. The curvatures of the NSs are calculated with the variation of baryon density.…

Nuclear Theory · Physics 2021-11-29 H. C. Das , Ankit Kumar , Bharat Kumar , S. K. Biswal , S. K. Patra

Among the many different classes of stellar objects, neutron stars provide a unique environment where we can test (at the same time) our understanding of matter with extreme density, temperature, and magnetic field. In particular, the…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Nanda Rea

The properties of matter are significantly modified by strong magnetic fields, $B>>2.35\times 10^9$ Gauss ($1 G =10^{-4} Tesla$), as are typically found on the surfaces of neutron stars. In such strong magnetic fields, the Coulomb force on…

Astrophysics · Physics 2008-11-26 Dong Lai

A neutron star with mass close to the lower limit might be a reasonable model for some anomalous pulsars. Emission is thermal. X-ray luminosity is high. Spatial velocity can be high. Since the radius is predicted to be large, the magnetic…

Astrophysics · Physics 2007-05-23 Frederick D. Seward

Astrophysics gives evidence for the existence of Dark Matter and puts constraints on its nature. The Cold Dark Matter model has become "standard" cosmology combined with a cosmological constant. There are indications that "Cold" Dark Matter…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Charling Tao

We investigate the equations of state for pure neutron matter and strange hadronic matter in $\beta$-equilibrium, including $\Lambda$, $\Sigma$ and $\Xi$ hyperons. The masses and radii of pure neutron stars and strange hadronic stars are…

Nuclear Theory · Physics 2010-02-17 P. Wang , S. Lawley , D. B. Leinweber , A. W. Thomas , A. G. Williams

Compact relativistic stars allow us to study the nature of matter under extreme conditions, probing regions of parameter space that are otherwise inaccessible. Nuclear theory in this regime is not well constrained: one key issue is whether…

Astrophysics · Physics 2008-11-26 Anna L. Watts , Sanjay Reddy

We review theoretical developments in studies of dense matter and its phase structure of relevance to compact stars. Observational data on compact stars, which can constrain the properties of dense matter, are presented critically and…

Astrophysics · Physics 2008-11-26 Dany Page , Sanjay Reddy

The generic acceleration model for ultra high energy cosmic rays, which has been introduced in {\tt 1006.5708 [astro-ph.HE]}, suggests various types of electromagnetic interactions between cosmic charged particles and the different types of…

High Energy Astrophysical Phenomena · Physics 2014-03-18 A. Tawfik , A. Saleh

The nature of the dark matter in the haloes of galaxies is one of the outstanding questions in astrophysics. All stellar candidates, until recently thought to be likely baryonic contributions to the Halo of our Galaxy, are shown to be ruled…

Astrophysics · Physics 2009-10-31 Katherine Freese , Brian D. Field , David S. Graff

We demonstrate that the largest measured mass of a neutron star establishes an upper bound to the energy density of observable cold matter. An equation of state-independent expression satisfied by both normal neutron stars and self-bound…

Astrophysics · Physics 2009-11-10 James M. Lattimer Madappa Prakash

In accordance with current models of the accelerating Universe as a spacetime with a positive cosmological constant, new results about a cosmological upper bound for the area of stable marginally outer trapped surfaces are found taking into…

General Relativity and Quantum Cosmology · Physics 2022-10-11 Tetsuya Shiromizu , Keisuke Izumi , Kangjae Lee , Diego Soligon

Neutron stars are the endpoint of the life of intermediate mass stars and posses in their cores matter in the most extreme conditions in the universe. Besides their extremes of temperature (found in proto-neutron stars) and densities,…

High Energy Astrophysical Phenomena · Physics 2018-06-07 R. O. Gomes , S. Schramm , V. Dexheimer

Self-annihilation of dark matter accreted from the galactic halo in the inner regions of neutron stars may affect their kinematical properties, namely velocity kicks and rotation patterns. We find that if a stable long-lived single or…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-16 M. Angeles Perez-Garcia , Joseph Silk

Mach's "fixed stars" are actually not fixed at all. The distant clusters of galaxies are not only receding from each observer but they are also accelerating since the rate of cosmological expansion is not constant. If the distant cosmic…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Scott Funkhouser

The existence of massive compact stars $(M\gtrsim 2.1 M_{\odot})$ implies that the conformal limit of the speed of sound $c_s^2=1/3$ is violated if those stars have a crust of ordinary nuclear matter. Here we show that, if the most massive…

High Energy Astrophysical Phenomena · Physics 2022-04-20 Silvia Traversi , Prasanta Char , Giuseppe Pagliara , Alessandro Drago

At the supranuclear densities achieved inside a neutron star, matter may exhibit extreme properties. In particular, it may be the case that a suitable average of the speed of sound squared exceeds the so-called conformal limit, i.e.,…

General Relativity and Quantum Cosmology · Physics 2024-12-02 Raissa F. P. Mendes , Caroline F. Sodré , Felipe T. Falciano