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The disciplines of asteroseismology and extrasolar planet science overlap methodically in the branch of high-precision photometric time series observations. Light curves are, amongst others, useful to measure intrinsic stellar variability…

Solar and Stellar Astrophysics · Physics 2010-05-20 Sonja Schuh

We present a theoretical background for the data analysis of the gravitational-wave signals from spinning neutron stars for Earth-based laser interferometric detectors. We introduce a detailed model of the signal including both the…

General Relativity and Quantum Cosmology · Physics 2009-12-30 Piotr Jaranowski , Andrzej Królak , Bernard F. Schutz

The search for faint emission or absorption lines in astronomical spectra has received considerable attention in recent years, especially in the X-ray wavelength range. These features usually appear as a deficit or excess of counts in a…

High Energy Astrophysical Phenomena · Physics 2018-10-05 Massimiliano Bonamente

This thesis investigates in the time domain a particular class of second order perturbations of a perfect fluid non-rotating compact star: those arising from the coupling between first order radial and non-radial perturbations. This problem…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Andrea Passamonti

Asteroseismology has opened a window on the internal physics of thousands of stars, by relating oscillation spectra properties to the internal physics of stars. Mode identification, namely the process of associating a measured oscillation…

Solar and Stellar Astrophysics · Physics 2022-09-21 Giovanni Marcello Mirouh

Context. The Blazhko effect, in RR Lyrae type stars, is a century old mystery. Dozens of theory exists, but none have been able to entirely reproduce the observational facts associated to this modulation phenomenon. Existing theory all rely…

Solar and Stellar Astrophysics · Physics 2016-10-25 Cyrus Zalian

Radio observations from normal pulsars indicate that the coherent radio emission is excited by curvature radiation from charge bunches. In this review we provide a systematic description of the various observational constraints on the radio…

High Energy Astrophysical Phenomena · Physics 2024-06-03 Dipanjan Mitra , Rahul Basu , George I Melikizde

Aims. The wavelet transform has been used as a powerful tool for treating several problems in astrophysics. In this work, we show that the time-frequency analysis of stellar light curves using the wavelet transform is a practical tool for…

Instrumentation and Methods for Astrophysics · Physics 2014-09-05 J. P. Bravo , S. Roque , R. Estrela , I. C. Leão , J. R. De Medeiros

Linear time-domain simulations of acoustic oscillations are unstable in the stellar convection zone. To overcome this problem it is customary to compute the oscillations of a stabilized background stellar model. The stabilization, however,…

Solar and Stellar Astrophysics · Physics 2013-12-17 Emanuele Papini , Laurent Gizon , Aaron C. Birch

In the context of the space-based mission CoRoT, devoted to asteroseismology and search for planet transits, we analyse the accuracy of fundamental stellar parameters (mass, radius, luminosity) that can be obtained from asteroseismological…

Solar and Stellar Astrophysics · Physics 2015-05-13 C. Mulet-Marquis , I. Baraffe , S. Aigrain , F. Pont

High-quality data from space-based observatories present an opportunity to fit stellar models to observations of individually-identified oscillation frequencies, not just the large and small frequency separations. But such fits require the…

Solar and Stellar Astrophysics · Physics 2015-06-17 Warrick H. Ball , Jesper Schou , Laurent Gizon , João P. Marques

We introduce a method for extracting spectral information from energy-resolved light curves folded at the neutron star spin period (known as pulse profiles) in accreting X-ray binaries. Spectra of these sources are sometimes characterized…

High Energy Astrophysical Phenomena · Physics 2023-09-13 Carlo Ferrigno , Antonino D'Aì , Elena Ambrosi

A new method for solving non-autonomous ordinary differential equations is proposed, the method achieves spectral accuracy. It is based on a new result which expresses the solution of such ODEs as an element in the so called…

Numerical Analysis · Mathematics 2022-10-03 Stefano Pozza , Niel Van Buggenhout

Young pulsars deviate from a perfectly regular spin-down by two non-deterministic phenomena: impulsive glitches and timing noise. Both phenomena are interesting per se, and may provide insights into the superfluid properties of neutron…

High Energy Astrophysical Phenomena · Physics 2023-02-17 Marco Antonelli , Avishek Basu , Brynmor Haskell

We present a new survey of the radial oscillation modes of neutron stars. This study complements and corrects earlier studies of radial oscillations. We present an extensive list of frequencies for the most common equations of state and…

General Relativity and Quantum Cosmology · Physics 2011-05-23 Kostas. D. Kokkotas , Johannes Ruoff

The spectrum of oscillating compact objects can be considerably altered in alternative theories of gravity. In particular, it may be enriched by modes with no counterpart in general relativity, tied to the dynamics of additional degrees of…

General Relativity and Quantum Cosmology · Physics 2022-01-21 Raissa F. P. Mendes , Néstor Ortiz , Nikolaos Stergioulas

This paper introduces the novel class of modulated cyclostationary processes, a class of non-stationary processes exhibiting frequency coupling, and proposes a method of their estimation from repeated trials. Cyclostationary processes also…

Methodology · Statistics 2012-10-25 Sofia C. Olhede , Hernando Ombao

We propose a new information theoretic metric for finding periodicities in stellar light curves. Light curves are astronomical time series of brightness over time, and are characterized as being noisy and unevenly sampled. The proposed…

Instrumentation and Methods for Astrophysics · Physics 2014-12-08 Pablo Huijse , Pablo A. Estevez , Pavlos Protopapas , Pablo Zegers , Jose C. Principe

We present an overview of the Velocity Coordinate Spectrum (VCS), a new technique for studying astrophysical turbulence that utilizes the line-of-sight statistics of Doppler-broadened spectral lines. We consider the retrieval of turbulence…

Astrophysics of Galaxies · Physics 2009-02-03 D. Pogosyan , A. Lazarian

We discuss a new technique for studying astrophysical turbulence that utilizes the statistics of Doppler-broadened spectral lines. The technique relates the power Velocity Coordinate Spectrum (VCS), i.e. the spectrum of fluctuations…

Astrophysics · Physics 2009-11-11 A. Lazarian , D. Pogosyan