Related papers: Constraints on Torque-Reversing Accretion-Powered …

We elaborate on a recently proposed model for subsonic quasi-spherical accretion onto slowly rotating pulsars, in which accretion is mediated through a hot quasi-static shell above the neutron star magnetosphere. We show that under the same…

Transitional millisecond pulsars (tMSPs) switch, on roughly multi-year timescales, between rotation-powered radio millisecond pulsar (RMSP) and accretion-powered low-mass X-ray binary (LMXB) states. The tMSPs have raised several questions…

The millisecond pulsar PSR B1620-26, in the globular cluster M4, has a white dwarf companion in a half-year orbit. Anomalously large variations in the pulsar's apparent spin-down rate have suggested the presence of a second companion in a…

We represent noise strength analysis of Anomalous X-Ray Pulsars (AXPs) 4U 0142+61, 1RXS J170849.9-400910, 1E 1841-045, 1E 2259+586 and Soft Gamma Repeaters (SGRs) SGR J1833-0832, SWIFT J1822.3-1606 and SWIFT J1834.9-0846 together with the…

We have detected quasi-periodic oscillations (QPOs) near 1 kHz from the low mass X-ray binary 4U 0614+091 in observations with XTE. The observations span several months and sample the source over a large range of X-ray luminosity. In every…

We describe observations of the 2003 outburst of the hard-spectrum X-ray transient 4U 1901+03 with the Rossi X-ray Timing Explorer. The outburst was first detected in 2003 February by the All-Sky Monitor, and reached a peak 2.5-25 keV flux…

We aim both to complement the existing data on the spin history of the peculiar accreting X-ray pulsar GX 1+4 with more past and current data from BeppoSAX, INTEGRAL, and Fermi and to interpret the evolution in the framework of accretion…

Cen X-3 shows alternate spin-up/spin-down episodes lasting for tens of days. We study the orbital profiles and spectra of Cen X-3 during these spin-up/spin-down intervals, using long-term data monitored by Fermi/GBM, Swift/BAT and MAXI/GSC.…

We report on a long X-ray observation of the slow-rotating binary pulsar GX 1+4. BeppoSAX observed, in the 0.1-200 keV energy range, an event in which the source flux dropped for almost a day, and then recovered. During this event only the…

The low mass X-ray binary 2A 1822-371 is an eclipsing system with an accretion disc corona and with an orbital period of 5.57 hr. The primary is an 0.59 s X-ray pulsar with a proposed strong magnetic field of 10^10-10^12 G. In this paper we…

The measurement of the spin frequency in accreting millisecond X-ray pulsars (AMXPs) is strongly affected by the presence of an unmodeled component in the pulse arrival times called 'timing noise'. We show that it is possible to attribute…

We present results of the first dedicated observation of the young X-ray pulsar SXP 1062 in the broad X-ray energy band obtained during its 2019 outburst with the NuSTAR and XMM-Newton observatories. The analysis of the pulse-phase averaged…

We summarize five years of continuous monitoring of accretion-powered pulsars with the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory. Our 20-70 keV observations have determined or refined the orbital…

IGR J18245-2452 is the fifteenth discovered accreting millisecond X-ray pulsar and the first source of this class showing direct evidence for transition between accretion and rotational powered emission states. These swing provided the…

The accretion-induced pulse-period changes of the Be/X-ray binary pulsar X Persei were investigated over a period of 1996 January to 2017 September. This study utilized the monitoring data acquired with the RXTE/ASM in 1.5$-$12 keV and…

We report results from an observation with the XMM-Newton observatory of a unique X-ray pulsar 4U 1626-67. EPIC-pn data during the current spin-up phase of 4U 1626-67 have been used to study pulse phase dependence of low energy emission…

Millisecond x-ray pulsars have weak magnetic dipole moments of $\sim 10^{16}$\,T\,m$^3$ compared to ordinary X-ray pulsars with dipole moments of $10^{20}$\,T\,m$^3$. For this reason a surrounding accretion disc can extend closer to the…

Millisecond spinning, low magnetic field neutron stars are believed to attain their fast rotation in a 0.1-1 Gyr-long phase during which they accrete matter endowed with angular momentum from a low-mass companion star. Despite extensive…

We report the detection of mHz quasi-periodic oscillations (QPOs) in four NuSTAR observations of 4U 1626-67 during its recent spin-down episode. By using a novel method based on the Hilbert-Huang Transform (HHT), we present the first…

We have studied the aperiodic variability of the 401 Hz accreting millisecond X-ray pulsar SAX J1808.4-3658 using the complete data set collected with the Rossi X-ray Timing Explorer over 14 years of observation. The source shows a number…