Related papers: The $\textit{False Widow}$ Link Between Neutron St…
We show that stable disk accretion should be very rare among low-mass X-ray binaries and cataclysmic variables whose evolution is driven by the nuclear expansion of the secondary star on the first giant branch. Stable accretion is confined…
We present the first results from a joint XMM-Newton and NuSTAR observation of the gamma-ray emitting millisecond pulsar compact binary PSR J2129-0429. X-ray emission up to about 40 keV is detected and the joint spectrum can be modeled with…
The intrabinary shocks (IBS) of spider pulsars emit non-thermal synchrotron X-rays from accelerated electrons and positrons in the shocked pulsar wind, likely energized by magnetic reconnection. In redback spider pulsars, the IBS typically…
Radio timing observations of millisecond pulsars (MSPs) in support of Fermi LAT observations of the gamma-ray sky enhance the sensitivity of high-energy pulsation searches. With contemporaneous ephemerides we have detected gamma-ray…
Millisecond pulsars (MSPs) orbiting helium white dwarfs (WDs) in eccentric orbits challenge the established binary evolution paradigm that predicts efficient orbital circularization during the mass transfer episode that spins up the pulsar.…
We identify and quantify the set of constraints that neutron star-normal star binaries must satisfy in order to become observable LMXBs. These constraints are related to (i) the thermal and hydrostatic equilibrium of the donors, (ii) the…
Using the 1.3m and 2.4m telescopes of the MDM Observatory, we identified the close companions of two eclipsing millisecond radio pulsars discovered by the Green Bank Telescope in searches of Fermi Gamma-ray Space Telescope sources, and…
Millisecond pulsars (MSPs) are believed to be old neutron stars, formed via Type Ib/c core-collapse supernovae, which have subsequently been spun up to high rotation rates via accretion from a companion star in a highly circularised…
Stellar evolutionary models predict that most of the early type subdwarf stars in close binary systems have white dwarf companions. More massive companions, such as neutron stars or black holes, are also expected in some cases. The presence…
X-ray eclipse mapping is a promising modelling technique, capable of constraining the mass and/or radius of neutron stars (NSs) or black holes (BHs) in eclipsing binaries and probing any structure surrounding the companion star. In…
Millisecond pulsars (MSPs) are prolific GeV $\gamma\text{-ray}$ emitters, and nearly 80\% of Fermi-LAT MSPs reside in compact binaries. We demonstrate that the companions in these compact MSPs binaries are also 511 keV annihilation line…
Properties of X-ray luminosities in low-mass X-ray binaries (LMXBs) mainly depend on donors. We have carried out a detailed study of donors in persistent neutron-star LMXBs (PLMXBs) by means of a population synthesis code. PLMXBs with…
We investigate the correlation between the frequencies of the twin kilohertz quasi-periodic oscillations (kHz QPOs) and the neutron star (NS) spins in low mass X-ray binaries (LMXBs), based on the data sets of 12 sources with simultaneously…
Black widows are extreme millisecond pulsar binaries where the pulsar wind ablates their low-mass companion stars. Their optical light curves vary periodically due to the high irradiation and tidal distortion of the companion, which allows…
We present the first X-ray observation of the energetic millisecond pulsar binary PSR J1431-4715, performed with XMM-Newton and complemented with fast optical multi-band photometry acquired with the ULTRACAM instrument at ESO-NTT. It is…
The Galactic population of rotation-powered (aka radio) millisecond pulsars (MSPs) exhibits diverse X-ray properties. Energetic MSPs show pulsed non-thermal radiation from their magnetospheres. Eclipsing binary MSPs predominantly have X-ray…
Neutron stars in high-mass X-ray binaries (HMXBs) generally accrete from the wind matter of their massive companion stars. Recently Shakura et al. (2012) suggested a subsonic accretion model for low-luminosity ($<4\times 10^{36}$…
We present a model for pulsar radio eclipses in some binary systems, and test this model for PSRs B1957+20 and J2051-0827. We suggest that in these binaries the companion stars are degenerate dwarfs with strong surface magnetic fields. The…
Long secondary periods (LSPs), observed in a third of pulsating red giant stars, are the only unexplained type of large-amplitude stellar variability known at this time. Here we show that this phenomenon is a manifestation of a substellar…
We report the discovery of peculiar X-ray spectral variability in the binary radio millisecond pulsar PSR J0024--7204W in the globular cluster 47 Tucanae. The observed emission consists of a dominant non-thermal component, which is eclipsed…