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We explore static spherically symmetric stars in the Gauss-Bonnet gravity without cosmological constant, and present an exact internal solution which attaches to the exterior vacuum solution outside stars. It turns out that the presence of…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Kang Zhou , Zhan-Ying Yang , De-Cheng Zou , Rui-Hong Yue

In this work we study weighted Radon transforms in multidimensions. We introduce an analog of Chang approximate inversion formula for such transforms and describe all weights for which this formula is exact. In addition, we indicate…

Functional Analysis · Mathematics 2016-12-09 Fedor Goncharov , Roman Novikov

$f(R)$ theories of gravity are one of the most popular alternative explanations for dark energy and therefore studying the possible astrophysical implications of these theories is an important task. In the present paper we make a…

General Relativity and Quantum Cosmology · Physics 2015-06-23 Stoytcho S. Yazadjiev , Daniela D. Doneva , Kostas D. Kokkotas

Modelling isolated rotating stars at any rotation rate is a challenge for the next generation of stellar models. These models will couple dynamical aspects of rotating stars, like angular momentum and chemicals transport, with classical…

Solar and Stellar Astrophysics · Physics 2015-06-11 Michel Rieutord , Francisco Espinosa Lara

This work introduces a novel and general class of continuous transforms based on hierarchical Voronoi based refinement schemes. The resulting transform space generalizes classical approaches such as wavelets and Radon transforms by…

Numerical Analysis · Mathematics 2025-04-04 Zachary Mullaghy

We consider the transformation for the point rotation frames with the angle, spatial coordinate along the axis of rotation and time as variables. The problem arises when light, propagating through 3-fold electrooptical crystal, is modulated…

Optics · Physics 2007-10-24 Boris V. Gisin

In this paper, we address an alternative formulation for the exact inverse formula of the Radon transform on circle arcs arising in a modality of Compton Scattering Tomography in translational geometry proposed by Webber and Miller (Inverse…

Numerical Analysis · Mathematics 2021-12-06 Cécilia Tarpau , Javier Cebeiro , Geneviève Rollet , Mai K. Nguyen , Laurent Dumas

Screening mechanisms are often deployed by dark energy models in order to conceal the effects of their new degrees of freedom from the scrutiny of terrestrial and solar system experiments. However, extreme properties of nuclear matter may…

General Relativity and Quantum Cosmology · Physics 2021-12-08 Bernardo F. de Aguiar , Raissa F. P. Mendes , F. T. Falciano

Mass and radius measurements of stars are important inputs for models of stellar structure. Binary stars are of particular interest in this regard, because astrometry and spectroscopy of a binary together provide the masses of both stars as…

Instrumentation and Methods for Astrophysics · Physics 2021-09-22 Km Nitu Rai , Soumen Basak , Prasenjit Saha

The spatial resolution of astronomical images is limited by atmospheric turbulence and diffraction in the telescope optics, resulting in blurred images. This makes it difficult to accurately measure the brightness of blended objects because…

Instrumentation and Methods for Astrophysics · Physics 2023-05-31 Kevin Michalewicz , Martin Millon , Frédéric Dux , Frédéric Courbin

The atmospheres of planets (including Earth) and the outer layers of stars have often been treated in radiative transfer as plane-parallel media, instead of spherical shells, which can lead to inaccuracy, e.g. limb darkening. We give an…

Statistical Mechanics · Physics 2009-11-11 Michael J. Caola

We define a noncommutative Lorentz symmetry for canonical noncommutative spaces. The noncommutative vector fields and the derivatives transform under a deformed Lorentz transformation. We show that the star product is invariant under…

High Energy Physics - Theory · Physics 2009-11-10 Xavier Calmet

The conical Radon transform is an integral transform that maps a given function $f$ to its integral over a conical surface. In this study, we invesgate the conical Radon transform with a fixed central axis and opening angle, considering the…

Functional Analysis · Mathematics 2024-09-23 Gihyeon Jeon

Superradiance in black holes is well-understood but a general treatment for superradiance in stars has until now been lacking. This is surprising given the ease with which we can observe isolated neutron stars and the array of signatures…

High Energy Physics - Phenomenology · Physics 2022-12-14 Francesca Chadha-Day , Björn Garbrecht , Jamie McDonald

Many of the general-relativity-tests such as bending of light near a star and gravitational red/blue shift are explained without general-relativity and without Newtonian-approach. The author first casts doubts on both, the Newtonian and the…

General Physics · Physics 2007-05-23 Dr. R. C. Gupta

In this paper, we consider the lens hyperbolic gamma solution to the star-star relation and the flipping relation from three-dimensional $\mathcal{N}=2$ supersymmetric gauge theories on $S^3_b/\mathbb{Z}_r$. We explore that a certain limit…

High Energy Physics - Theory · Physics 2025-08-28 Erdal Catak , Mustafa Mullahasanoglu

We present raytracing computations for light emitted from the surface of a rapidly-rotating neutron star in order to construct light curves for X-ray pulsars and bursters. These calculations are for realistic models of rapidly-rotating…

Astrophysics · Physics 2011-02-11 Coire Cadeau , Sharon M. Morsink , Denis Leahy , Sheldon S. Campbell

The possibility of neutron swapping between the ordinary and mirror sectors is today a subject of a great many theoretical and experimental studies. In this paper, we investigate the neutron-mirror neutron transitions in different…

High Energy Physics - Phenomenology · Physics 2022-07-27 B. O. Kerbikov

Rotating deformed neutron stars are important potential sources for groundbased gravitational-wave interferometers such as LIGO, GE0600 and VIRGO. One mechanism that may lead to significant non-asymmetries is the internal magnetic field. It…

Astrophysics · Physics 2009-11-13 B. Haskell , L. Samuelsson , K. Glampedakis , N. Andersson

The spectral flux density of stars can indicate their atmospheric physical properties. A detector can obtain any band flux density at the design stage. However, the band flux density is confirmed and fixed in the process of operation…

Instrumentation and Methods for Astrophysics · Physics 2018-09-26 Chuanxin Zhang , Yuan Yuan , Zhaoyang Yu , Fuqiang Wang , Heping Tan