Search results for "XTE J1807-294"

showing 3 items of 3 documents

Spin up and phase fluctuations in the timing of the accreting millisecond pulsar XTE J1807-294

2007

We performed a timing analysis of the 2003 outburst of the accreting X-ray millisecond pulsar XTE J1807-294 observed by RXTE. Using recently refined orbital parameters we report for the first time a precise estimate of the spin frequency and of the spin frequency derivative. The phase delays of the pulse profile show a strong erratic behavior superposed to what appears as a global spin-up trend. The erratic behavior of the pulse phases is strongly related to rapid variations of the light curve, making it very difficult to fit these phase delays with a simple law. As in previous cases, we have therefore analyzed separately the phase delays of the first harmonic and of the second harmonic of …

Orbital elementsPhysicsAstrophysics::High Energy Astrophysical PhenomenaAstrophysics (astro-ph)Phase (waves)Static timing analysisFOS: Physical sciencesAstronomy and AstrophysicsAstrophysicsLight curveAstrophysicsPulsars: General Stars: Pulsars: Individual: Alphanumeric: XTE J1807-294 Stars: Magnetic Fields Stars: Neutron X-Rays: Binaries [Stars]Pulse (physics)Settore FIS/05 - Astronomia E AstrofisicaSpace and Planetary ScienceMillisecond pulsarHarmonicStars: Pulsars: General Stars: Pulsars: Individual: Alphanumeric: XTE J1807-294 Stars: Magnetic Fields Stars: Neutron X-Rays: BinariesSpin-½
researchProduct

Precise determination of orbital parameters in system with slowly drifting phases: application to the case of XTE J1807-294

2007

We describe a timing technique that allows to obtain precise orbital parameters of an accreting millisecond pulsar in those cases in which intrinsic variations of the phase delays (caused e.g. by proper variation of the spin frequency) with characteristic timescale longer than the orbital period do not allow to fit the orbital parameters over a long observation (tens of days). We show under which conditions this method can be applied and show the results obtained applying this method to the 2003 outburst observed by RXTE of the accreting millisecond pulsar XTE J1807-294 which shows in its phase delays a non-negligible erratic behavior. We refined the orbital parameters of XTE J1807-294 usin…

Orbital elementsPhysicspulsars : individualAstrophysics::High Energy Astrophysical PhenomenaAstrophysics (astro-ph)Phase (waves)pulsars : generalFOS: Physical sciencesstars : magnetic fieldAstronomy and AstrophysicsAstrophysicsOrbital periodAstrophysicsstars : neutronX-ray : binariesXTE J1807-294Space and Planetary ScienceMillisecond pulsarAstrophysics::Earth and Planetary AstrophysicsSpin (physics)Variation (astronomy)magnetic fields; stars : neutron; pulsars : general; pulsars : individual; XTE J1807-294; X-ray : binaries [stars]Order of magnitude
researchProduct

A model to interpret pulse phase shifts in AMXPs: SAX J1808.4-3658 as a proof of concept

2011

Abstract: Observational evidences of erratic 1(st) harmonic pulse phase shifts in accreting millisecond X-ray pulsars pulse phase evolution was reported by several authors. This effect always go together with much more stable 2(nd) harmonics pulse phase delays. Different possible explanations of these phase shifts have been given in literature. But all these interpretations do not explain why the 2(nd) harmonic are more stable than the 1(st) harmonic. The explanation of such a behaviour is of fundamental importance in order to gain an insight on the NS rotational behaviour and to remove the still present interpretative ambiguity on the results of timing analysis. We propose a simple toy-mod…

PhysicsMillisecondstars: magnetic fieldPhase (waves)Static timing analysispulsars: individual: XTE J1807-294Computational physicsPulse (physics)stars: neutronTheoretical physicsSettore FIS/05 - Astronomia E AstrofisicaAmplitudePulsarpulsars: generalHarmonicsHarmonicX-ray: binariesAIP Conference Proceedings
researchProduct