Related papers: A pulsar in a binary with a compact object in the …
We have used the Green Bank Telescope to observe the millisecond pulsar PSR J0514-4002A on 43 occasions spread over 2 years. This 5-ms pulsar is located in the globular cluster NGC 1851; it belongs to a binary system and has a highly…
Binary neutron-star mergers will predominantly produce black-hole remnants of mass $\sim 3-4\,M_{\odot}$, thus populating the putative \emph{low mass gap} between neutron stars and stellar-mass black holes. If these low-mass black holes are…
Can one distinguish a binary black hole undergoing a merger from a binary neutron star if the individual compact companions have masses that fall inside the so-called mass gap of $3-5\ M_\odot$? For neutron stars, achieving such masses…
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…
Mass distribution of black holes in low-mass X-ray binaries previously suggested the existence of a $ \sim 2-5M_{\odot} $ mass gap between the most massive neutron stars and the least massive black holes, while some recent evidence appears…
Many physically motivated extensions to general relativity (GR) predict significant deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 +/- 0.04 solar mass pulsar in a 2.46-hr…
Recent gravitational wave observations include possible detections of black hole - neutron star binary mergers. As with binary black hole mergers, numerical simulations help characterize the sources. For binary systems with neutron star…
The recent discovery by LIGO/Virgo of a merging binary having a $\sim 23 M_\odot$ black hole and a $\sim 2.6 M_\odot$ compact companion has triggered a debate regarding the nature of the secondary, which falls into the so-called mass gap.…
Observations of X-ray binaries indicate a dearth of compact objects in the mass range from $\sim 2-5 M_{\odot}$. The existence of this (first mass) gap has been used to discriminate between proposed engines behind core-collapse supernovae.…
In this letter we focus on the peculiar case of a coalescing compact-object binary whose chirp mass is compatible both with a neutron star-neutron star and black hole-neutron star system, with the black hole in the $\sim 3-5M_\odot$ range…
The maximum mass of a neutron star has important implications across multiple research fields, including astrophysics, nuclear physics and gravitational wave astronomy. Compact binary millisecond pulsars (with orbital periods shorter than…
A stellar common envelope occurs in a binary system when the atmosphere of an evolving star expands to encompass an orbiting companion object. Such systems are predicted to evolve rapidly, ejecting the stellar envelope and leaving the…
Although gravitational-wave signals from exceptional low-mass compact binary coalescences, like GW170817, may carry matter signatures that differentiate the source from a binary black hole system, only one out of every eight events detected…
Depending principally on mass, the compact object remnant left behind after a star's life may be a white dwarf (WD), neutron star (NS), or black hole (BH). While we have large samples of each of these remnants, we lack knowledge of the…
We estimate the mass of the compact object in the gamma-ray binaries LSI+61303 and MWC 148, using the latest data for the inclination, orbital motion and assuming that the orbital plane coincides with the equatorial plane of the Be star.…
The properties of rotating neutron stars are investigated using eight equations of state (EOSs). We also study the relations between various observables corresponding to different angular velocities for all those EOSs. All of these EoSs…
We have performed population synthesis calculation on the formation of binaries containing a black hole (BH) and a neutron star (NS) in the Galactic disk. Some of important input parameters, especially for the treatment of common envelope…
We report the discovery of PSR J1757$-$1854, a 21.5-ms pulsar in a highly-eccentric, 4.4-h orbit around a neutron star (NS) companion. PSR J1757$-$1854 exhibits some of the most extreme relativistic parameters of any known pulsar, including…
Compact objects observed via gravitational waves are classified as black holes or neutron stars primarily based on their inferred mass with respect to stellar evolution expectations. However, astrophysical expectations for the lowest mass…
The existence of compact stellar remnants in the mass range $2-5\,M_{\odot}$ has long been debated. This so-called lower mass gap was initially suggested by the lack of low-mass X-ray binary observations with accretors about…