Related papers: Energy-resolved pulse profiles of accreting pulsar…
We review the results of a timing analysis of the observations for ten bright X-ray pulsars (with fluxes >100 mCrab in the 20-100 keV energy band) that fell within the INTEGRAL field of view from 2003 to 2007. The dependence of the pulse…
A great deal of emphasis on timing in the RXTE era has been on pushing toward higher and higher frequency phenomena, particularly kHz QPOs. However, the large areas of the RXTE pointed instruments provide another capability which is key for…
Using a consistent set of models, we parameterized the X-ray spectra of all accreting pulsars in the Rossi X-ray Timing Explorer database which exhibit Cyclotron Resonance Scattering Features (CRSFs, or cyclotron lines). These sources in…
The paper presents model pulse profiles from binary accreting X-ray pulsars using high-resolution numerical simulations for pencil and fan emission beam geometries, each with two different optical depths obtained using a new numerical code…
We describe the X-ray pulse profile models we use, and how we use them, to analyze Neutron Star Interior Composition Explorer (NICER) observations of rotation-powered millisecond pulsars to obtain information about the mass-radius relation…
It is expected that extreme mass accretion rate onto strongly magnetised neutron star results in appearance of accretion columns above stellar surface. For a distant observer, rotation of a star results in periodic variations of X-ray flux.…
The pulsed X-ray emission from the neutron star surface acts as a window to study the state of matter in the neutron star interior. For accreting millisecond pulsars, the surface X-ray emission is generated from the `hotspots' formed due to…
We present a Bayesian method to constrain the masses and radii of neutron stars (NSs) using the information encoded in the X-ray pulse profiles of accreting millisecond pulsars. We model the shape of the pulses using "oblate Schwarzschild"…
We applied a decomposition method to the energy dependent pulse profiles of the accreting binary pulsar A 0535+26, in order to identify the contribution of the two magnetic poles of the neutron star and to obtain constraints on the geometry…
Approximate analytical formulae are derived for the pulse profile produced by small hot spots on a rapidly rotating neutron star. Its Fourier amplitudes and phases are calculated. The proposed formalism takes into account gravitational…
We have simulated the X-ray polarization data that can be obtained with the Imaging X-ray Polarimetry Explorer, when observing accretion-powered millisecond pulsars. We estimated the necessary exposure times for SAX J1808.4$-$3658 in order…
We present the results of broad band (3-100 keV) observations of several X-ray pulsars with the INTEGRAL and RXTE observatories. We concentrate on the luminosity and energy dependence of the pulse profile and the variations of the cyclotron…
Context. Cyclotron resonant scattering features (CRSFs) in accreting X-ray pulsars are often difficult to detect, especially when shallow or variable. Recent studies have shown that combining spectral and timing analyses enhances their…
We calculate the photon energy dependence of the pulsed amplitude of neutron star (NS) surface modes. Simple approximations demonstrate that it depends most strongly on the bursting NS surface temperature. This result compares well with…
We have studied the temporal and spectral properties of SXP 15.3 observed by \textit{NuSTAR} in hard energy range 3-79 keV during late 2018. The timing analysis of \textit{NuSTAR} observation predicts coherent pulsation at…
A fraction of the Ultra Luminous X-ray (ULX) sources are known to be accreting neutron stars as they show coherent X-ray pulsations with pulse periods ranging from ~1-30 seconds. While initially thought to host intermediate-mass black…
We report on the Neutron Star Interior Composition Explorer (NICER) monitoring campaign of the 468 Hz accreting millisecond X-ray pulsar IGR J17379-3747. From a detailed spectral and timing analysis of the coherent pulsations we find that…
Some of the accreting X-ray pulsars are reported to exhibit a peculiar spectral feature at $\sim$10 keV, known as the "10 keV feature". The feature has been characterized as either an emission line or an absorption line, and its origin is…
We study the effects of the time-variable properties of thermonuclear X-ray bursts on modeling their millisecond-period burst oscillations. We apply the pulse profile modeling technique that is being used in the analysis of rotation-powered…
Vela X-1 is a well-studied accreting X-ray pulsar, with a distinctive pulse profile that has been found to be very similar in different observations spread out over decades. On the other hand, significant variations down to the timescale of…