A SHOT NOISE MODEL FOR A 2-COMPONENT NEUTRON-STAR

Date

1991-12-01

Author

Baykal, Altan
KIZILOGLU, U

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

117
views

0
downloads

The two component neutron star model and the response of the neutron star under the influence of external white torque noise are reviewed. A new simulation technique is developed for estimating the crust core coupling time and the moment of inertia of the superfluid in the neutron star from the irregularly sampled data. The model is applied to Vela X-1, since this source has a long period P = 283 s and theoretical estimates of crust-core coupling time which are proportional to P lie in the observable region, tau = 1 - 30 d for Vela X-1. In the analysis, it is found that moment of inertia of the superfluid cannot exceed 85% of the total moment inertia of the star if the crust core coupling time is longer than 1 d (tau > 1 d). This is in agreement with the analysis of Boynton et al. (1984) on earlier data. This result indicates that either the core superfluid mixture is less than 85% of the total moment of inertia of the star or the crust core coupling time should be less than 1 d.

Subject Keywords

X-RAY BINARIES, NEUTRON STARS, STOCHASTIC PROCESSES

URI

https://hdl.handle.net/11511/55833

Journal

ASTRONOMY & ASTROPHYSICS

Collections

Department of Physics, Article

Suggestions

OpenMETU
Core

AN EMPIRICAL TORQUE NOISE AND SPIN-UP MODEL FOR ACCRETION-POWERED X-RAY PULSARS Baykal, Altan (1993-01-01) By using the first order autoregressive time series model, rotation histories of accretion-powered X-ray pulsars are modeled yielding a torque noise strength S(in) and the average secular spin-up term [OMEGA]. We find that Her X-1, Cen X-3, A0535 + 26, and Vela X-1 can be modeled with white torque-noise leading to random walks in pulse frequency; for the remaining sources the random walk model is also acceptable. Using this model we calculate the noise strengths in the frequency derivative and estimate the ...
A Domain Decomposition Finite-Element Method for Modeling Electromagnetic Scattering From Rough Sea Surfaces With Emphasis on Near-Forward Scattering ÖZGÜN, ÖZLEM; Kuzuoğlu, Mustafa (Institute of Electrical and Electronics Engineers (IEEE), 2019-01-01) A high-fidelity full-wave simulator is presented to perform numerical experiments for rough sea scattering problem by considering different polarizations, frequencies, grazing angles, wind speeds, and sea surface spectra. The simulator is based on a novel finite-element domain decomposition (FEDD) method for solving the problem of 2-D electromagnetic scattering over 1-D sea surface. This noniterative method partitions the computational domain into a number of overlapping subdomains and solves each domain in...
A Deep Learning Approach to Proton Background Rejection for Positron Analysis with the AMS Electromagnetic Calorimeter Hashmani, Raheem Karim; Akbaş, Emre; Demirköz, Melahat Bilge; Department of Computer Engineering (2023-1-26) The Alpha Magnetic Spectrometer (AMS) is a high-precision particle detector onboard the International Space Station containing six different subdetectors. The Transition Radiation Detector and Electromagnetic Calorimeter (ECAL) are used to separate electrons/positrons from the abundant cosmic-ray proton background. The positron flux measured in space by AMS falls with a power law which unexpectedly softens above 25 GeV and then hardens above 280 GeV. Several theoretical models try to explain these phenomen...
A NUMERICAL-SIMULATION OF THE AXISYMMETRICAL VORTEX BREAKDOWN IN A TUBE Aksel, Mehmet Haluk; KAYA, MT (1992-08-01) The axisymmetric vortex breakdown of a laminar, incompressible, viscous, and swirling flow in a cylindrical tube is simulated. The numerical solutions of the time-dependent axisymmetric angular momentum and the vorticity transport equations are obtained by using the finite element method. Linear and quadratic isoparametric elements are used for the space discretization, while the leapfrog time integration scheme is employed for the time discretization. The iteration process is started with the numerical sol...
A comparative study of the electronic properties of aluminum nitride compounds Mohammad, Rezek; Katırcıoğlu, Şenay (2016-01-01) Electronic properties of aluminum nitride in wurtzite, zinc-blende, and rock-salt phases are investigated by a full potential-linearized augmented plane waves method based on density functional theory within standard local density approximation and its four improved versions. Local density approximation corrected by the generalized gradient functional of Perdew-Wang-Engel-Vosko is found to be more successful than the other generalized gradient functional approximations considered in this work for providing ...

Citation Formats

A. Baykal and U. KIZILOGLU, “A SHOT NOISE MODEL FOR A 2-COMPONENT NEUTRON-STAR,” ASTRONOMY & ASTROPHYSICS, pp. 664–668, 1991, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/55833.