Related papers: He star evolutionary channel to intermediate-mass …

Recent pulsar timing observations using MeerKAT of the eccentric binary millisecond pulsar, PSR J0514$-$4002E, have unveiled a companion with a mass in the mass gap, ranging from $2.09\, M_\odot$ to $2.71\, M_\odot$. This challenges…

We have identified a new intermediate polar, HS 0943+1404, as part of our ongoing search for cataclysmic variables in the Hamburg Quasar Survey. The orbital and white dwarf spin periods determined from time-resolved photometry and…

We investigate the possibility that mass transfer early in the evolution of a massive binary can effect a reversal of the end states of the two components, resulting in a neutron star which forms before a black hole. In this sense, such…

We examine the growing class of binary millisecond pulsars known as redbacks. In these systems the pulsar's companion has a mass between 0.1 and about 0.5 solar masses in an orbital period of less than 1.5 days. All show extended radio…

PSR J2032+4127 is a radio-loud gamma-ray-emitting pulsar; it is orbiting around a high-mass Be type star with a very long orbital period of 25-50years, and is approaching periastron, which will occur in late 2017/early 2018. This system…

The bright subdwarf-O star (sdO), HD 49798, is in a 1.55 day orbit with a compact companion that is spinning at 13.2 seconds. Using the measurements of the effective temperature ($T_{\rm eff}$), surface gravity ($\log g$), and surface…

PSR J1910-5959A is a binary pulsar with a helium white dwarf companion located about 6 arcmin from the center of the globular cluster NGC6752. Based on 12 years of observations at the Parkes radio telescope, the relativistic Shapiro delay…

Binary millisecond pulsars (MSPs) provide several opportunities for research of fundamental physics. However, finding them can be challenging. Several subdwarf B (sdB) binary systems with possible neutron star companions have been…

PSR J2215+5135 (J2215) is a `redback' spider pulsar, where the intrabinary shock (IBS) wraps around the pulsar rather than the stellar-mass companion. Spider orbital light curves are modulated, dominated by their binary companion thermal…

We present a scenario for the spin-up and evolution of binary millisecond pulsars. This can explain the observational properties of the recently discovered binary millisecond pulsar PSR J1740-5340, with orbital period 32.5 hrs, in the…

Here we report timing measurements of the relativistic binary pulsar PSR J1141-6545 that constrain the component masses and demonstrate that the orbital period derivative \dot Pb = (-4+/-1)x10^-13 is consistent with gravitational wave…

Binary systems consisting of a white dwarf and a main-sequence companion with orbital periods up to $\approx 100$ d are often thought to be formed through common envelope evolution which is still poorly understood. To provide new…

We report the discovery of SDSS~J022932.28+713002.7, a nascent extremely low-mass (ELM) white dwarf (WD) orbiting a massive ($> 1\,M_\odot$ at 2$\sigma$ confidence) companion with a period of 36 hours. We use a combination of spectroscopy,…

Extreme mass ratio inspirals (EMRIs) of low-mass white dwarfs (WDs, 0.1 - 0.3 Msun) around spinning intermediate-mass black holes (IMBHs, 10^3 - 10^5 Msun) offer unique opportunities for multi-messenger astronomy, emitting both…

A very recent and meticulous timing effort suggests that an eccentric millisecond pulsar (eMSP) binary, namely PSR J1618-3921, is likely to be a part of a hierarchical triple (HT) system with a $0.6M_{\odot}$ companion in a $\sim 300$yr…

A single-lined spectroscopic orbit for the M giant in the X-ray binary IGR J16194-2810 is determined from a time-series of optical spectra. The spectroscopic orbital period of 192.5 days is twice that of the photometric period, confirming…

The binary pulsar J0348+0432 was previously shown to have a mass of approximately 2\,${\rm M_\odot}$, based on the combination of radial-velocity and model-dependent mass parameters derived from high-resolution optical spectroscopy of its…

We present optical follow-up of IGR J16194-2810, a hard X-ray source discovered by the INTEGRAL mission. The optical counterpart is a $\sim500\,L_\odot$ red giant at a distance of $2.1$ kpc. We measured 17 radial velocities (RVs) of the…

We report the detections of two substellar companions orbiting around evolved intermediate-mass stars from precise Doppler measurements at Subaru Telescope and Okayama Astrophysical Observatory. HD 145457 is a K0 giant with a mass of 1.9…

The evolution of helium stars with masses of 1.5 - 6.7 M_sun in binary systems with a 1.4 M_sun neutron-star companion is presented. Such systems are assumed to be the remnants of Be/X-ray binaries with B-star masses in the range of 8 - 20…