Quasi-simultaneous Radio/X-Ray Observations of the Candidate Transitional Millisecond Pulsar 3FGL J1544.6?1125 during its Low-luminosity Accretion-disk State

Multi-wavelength Observations of 3fgl J2039.6–5618: a Candidate Redback Millisecond Pulsar

We present multi-wavelength observations of the unassociated γ-ray source 3FGL J2039.6−5618 detected by the Fermi Large Area Telescope. The source γ-ray properties suggest that it is a pulsar, most likely a millisecond pulsar, for which neither radio nor γ-ray pulsations have been detected. We observed 3FGL J2039.6−5618 with XMM-Newton and discovered several candidate X-ray counterparts within/...

Very low luminosities from the accretion-driven millisecond X-ray pulsar SAX J1808.4–3658 during quiescence

We have observed the millisecond X-ray pulsar SAX J1808.4–3658 on three occasions during its 2000 outburst with the BeppoSAX satellite. The source was highly variable and erratic during this outburst, and by coincidence we obtained data only during times when the source had very low luminosities. During our observations, we detected four faint sources. The source closest to the position of SAX ...

Discovery of the First Accretion-powered Millisecond X-ray Pulsar

Accretion-powered Millisecond Pulsar Outbursts

The population of accretion-powered millisecond pulsars (AMSPs) has grown rapidly over the last four years, with the discovery of six new examples to bring the total sample to seven. While the first six discovered are transients active for a few weeks every two or more years, the most recently-discovered source HETE J1900.1−2455, has been active for more than 8 months. We summarise the transien...

A precessing warped accretion disk around the X - ray pulsar

We have performed an analysis and interpretation of the X-ray light curve of the accreting neutron star Her X-1 obtained with the ASM RXTE over the period 1996 February to 2004 September. The averaged X-ray light curves are constructed by means of adding up light curves corresponding to different 35 day cycles. A numerical model is introduced to explain the properties of the averaged light curv...