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Related papers: Exotica in rotating compact stars

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Pulse profile modeling of X-ray data from NICER is now enabling precision inference of neutron star mass and radius. Combined with nuclear physics constraints from chiral effective field theory ($\chi$EFT), and masses and tidal…

We study the feasibility of detecting exotic cores in merging neutron stars with ground-based gravitational-wave detectors. We focus on models with a sharp nuclear/exotic matter interface, and assume a uniform distribution of neutron stars…

High Energy Astrophysical Phenomena · Physics 2020-04-08 Hsin-Yu Chen , Paul M. Chesler , Abraham Loeb

We summarize our current knowledge of neutron star masses and radii. Recent instrumentation and computational advances have resulted in a rapid increase in the discovery rate and precise timing of radio pulsars in binaries in the last few…

High Energy Astrophysical Phenomena · Physics 2016-10-05 Feryal Ozel , Paulo Freire

We present VLT intermediate resolution spectroscopy of UY Vol, the optical counterpart of the LMXB X-ray burster EXO 0748-676. By using Doppler tomography we detect narrow components within the broad He II 4542 A, 4686 A and 5412 A emission…

High Energy Astrophysical Phenomena · Physics 2009-11-13 T. Muñoz-Darias , J. Casares , K. O'Brien , D. Steeghs , I. G. Martinez-Pais , R. Cornelisse , P. A. Charles

It has been predicted that quark and hybrid stars, containing strange quark matter in their core, have a significantly smaller radius than ordinary neutron stars. Preliminary X-ray observations of isolated neutron stars indicated a…

Astrophysics · Physics 2009-11-07 Markus H. Thoma , Joachim Truemper , Vadim Burwitz

Recently, the neutron star X-ray binary EXO 0748-676 underwent a transition to quiescence. We analyzed an XMM-Newton observation of this source in quiescence, where we fitted the spectrum with two different neutron-star atmosphere models.…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Guobao Zhang , Mariano Mendez , Peter Jonker , Beike Hiemstra

We analyze observations of eight quiescent low-mass X-ray binaries in globular clusters and combine them to determine the neutron star mass-radius curve and the equation of state of dense matter. We determine the effect that several…

High Energy Astrophysical Phenomena · Physics 2018-02-14 A. W. Steiner , C. O. Heinke , S. Bogdanov , C. Li , W. C. G. Ho , A. Bahramian , S. Han

Neutron stars are compact objects rotating at high speed, up to a substantial fraction of the speed of light (up to 20\% for millisecond pulsars) and possessing ultra-strong electromagnetic fields (close to and sometimes above the quantum…

High Energy Astrophysical Phenomena · Physics 2020-01-13 Jérôme Pétri

Searches for continuous gravitational waves from \textit{unknown} Galactic neutron stars provide limits on the shapes of neutron stars. A rotating neutron star will produce gravitational waves if asymmetric deformations exist in its…

High Energy Astrophysical Phenomena · Physics 2021-11-09 Brendan T. Reed , Alex Deibel , C. J. Horowitz

The Neutron Star Interior Composition Explorer (NICER) recently measured the mass and equatorial radius of the isolated neutron star PSR J0030+0451. We use these measurements to infer the moment of inertia, the quadrupole moment, and the…

General Relativity and Quantum Cosmology · Physics 2021-05-06 Hector O. Silva , A. Miguel Holgado , Alejandro Cárdenas-Avendaño , Nicolás Yunes

We present a model of thermal X-ray emission from hot spots on the surface of a rotating compact star with an unmagnetized light-element atmosphere. An application to ROSAT, Chandra, and XMM-Newton X-ray observations of the nearest known…

Astrophysics · Physics 2009-11-11 Slavko Bogdanov , George B. Rybicki , Jonathan E. Grindlay

According to various models, the orbital and the epicyclic frequencies of particles moving on a circular orbit around compact objects are related to the quasi-periodic oscillations observed in the X-ray flux of some pulsars or black hole…

General Relativity and Quantum Cosmology · Physics 2016-01-27 Kalin V. Staykov , Daniela D. Doneva , Stoytcho S. Yazadjiev

The merger of binary neutron stars is likely to lead to differentially rotating remnants. In this paper, we survey several cold nuclear equations of state (EOSs) and numerically construct models of differentially rotating neutron stars in…

Astrophysics · Physics 2009-11-10 Ian A. Morrison , Thomas W. Baumgarte , Stuart L. Shapiro

A bound on the compactness of the neutron star in the low mass x-ray binary 4U 1636-53 is used to estimate the equation of state of neutron star matter at high density. Observations of 580 Hz oscillations during the rising phase of x-ray…

Astrophysics · Physics 2007-05-23 T. S. Olson

Recent constraints on neutron star mass and radius have advanced our understanding of the equation of state (EOS) of cold dense matter. Some of them have been obtained by modeling the pulses of three millisecond X-ray pulsars observed by…

Employing the Quark Mass Denisity- and temperature- dependent model and the Hartle's method, We have studied the slowly rotating strange star with uniform angular velocity. The mass-radius relation, the moment of inertia and the frame…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Jianyong Shen , Yun Zhang , Bin Wang , Ru-Keng Su

We propose an approximate description of basic parameters (radius, mass and oblateness) of general relativistic compact rotating objects in terms of the parameters of the static configuration and of the angular velocity only. The…

Astrophysics · Physics 2007-05-23 K. S. Cheng , T. Harko

Neutron stars are commonly considered as astronomical objects having highdensity interiors and an inner core region in which various hadronic matter phases are expected. Several studies show that the inner structures affect macroscopic…

High Energy Astrophysical Phenomena · Physics 2016-06-22 Tomoki Endo

I make the first estimates of maximum elastic quadrupole deformations sustainable by alternatives to conventional neutron stars. Solid strange quark stars might sustain maximum ellipticities (dimensionless quadrupoles) up to a few times…

Astrophysics · Physics 2007-05-23 Benjamin J. Owen

The binary pulsar J0737-3039 is the only known system having two observable pulsars, thus offering a unique laboratory to test general relativity and explore pulsar physics. Based on the low eccentricity and the position within the galactic…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Simone Dall'Osso , Tsvi Piran , Nir Shaviv