scholarly journals Masses of double neutron star mergers

2020 ◽  
Vol 639 ◽  
pp. A123 ◽  
Author(s):  
Matthias U. Kruckow
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Milky Way ◽  
Radio Pulsar ◽  
Population Synthesis ◽  
Radio Pulsars ◽  
Wave Observation ◽  
Binary Evolution ◽  
Star Binary

Aims. I aim to explain the mass discrepancy between the observed double neutron-star binary population by radio pulsar observations and gravitational-wave observation. Methods. I performed binary population synthesis calculations and compared their results with the radio and the gravitational-wave observations simultaneously. Results. Simulations of binary evolution were used to link different observations of double neutron star binaries with each other. I investigated the progenitor of GW190425 in more detail. A distribution of masses and merger times of the possible progenitors is presented. Conclusions. A mass discrepancy between the radio pulsars in the Milky Way with another neutron star companion and the inferred masses from gravitational-wave observations of those kind of merging systems is naturally found in binary evolution.

scholarly journals The expansion of stripped-envelope stars: Consequences for supernovae and gravitational-wave progenitors

2020 ◽  
Vol 637 ◽  
pp. A6 ◽  
Author(s):  
E. Laplace ◽  
Y. Götberg ◽  
S. E. de Mink ◽  
S. Justham ◽  
R. Farmer
Keyword(s):  
Mass Transfer ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Compact Objects ◽  
Population Synthesis ◽  
Outer Envelope ◽  
Low Metallicity ◽  
Binary Evolution ◽  
Ultimate Fate ◽  
High Metallicity

Massive binaries that merge as compact objects are the progenitors of gravitational-wave sources. Most of these binaries experience one or more phases of mass transfer, during which one of the stars loses all or part of its outer envelope and becomes a stripped-envelope star. The evolution of the size of these stripped stars is crucial in determining whether they experience further interactions and understanding their ultimate fate. We present new calculations of stripped-envelope stars based on binary evolution models computed with MESA. We use these to investigate their radius evolution as a function of mass and metallicity. We further discuss their pre-supernova observable characteristics and potential consequences of their evolution on the properties of supernovae from stripped stars. At high metallicity, we find that practically all of the hydrogen-rich envelope is removed, which is in agreement with earlier findings. Only progenitors with initial masses below 10 M⊙ expand to large radii (up to 100 R⊙), while more massive progenitors remain compact. At low metallicity, a substantial amount of hydrogen remains and the progenitors can, in principle, expand to giant sizes (> 400 R⊙) for all masses we consider. This implies that they can fill their Roche lobe anew. We show that the prescriptions commonly used in population synthesis models underestimate the stellar radii by up to two orders of magnitude. We expect that this has consequences for the predictions for gravitational-wave sources from double neutron star mergers, particularly with regard to their metallicity dependence.

Opening the window

2019 ◽  
pp. 1-22
Author(s):  
Nils Andersson
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Binary Event ◽  
Star Binary

This chapter provides a brief survey of gravitational-wave astronomy, including the recent recent breakthrough detection. It sets the stage for the rest of the book via simple back-of-the-envelope estimates for different sets of sources. The chapter also describes the first detection of a black hole merger (GW150914) as well as the first observed neutron star binary event (GW170817) and introduces some of the ideas required to understand these breakthroughs.

scholarly journals EARLY PHASES OF DIFFERENT TYPES OF ISOLATED NEUTRON STAR

2005 ◽  
Vol 14 (06) ◽  
pp. 1075-1082 ◽  
Author(s):  
AŞKIN ANKAY ◽  
SERKAN ŞAHIN ◽  
GÖKÇE KARANFIL ◽  
EFE YAZGAN
Keyword(s):  
Neutron Star ◽  
Thermal Neutron ◽  
Early Phase ◽  
Radio Pulsar ◽  
Radio Pulsars ◽  
X Ray ◽  
Soft Gamma Repeaters ◽  
Different Types ◽  
Early Phases

Two Galactic isolated strong X-ray pulsars seem to be in the densest environments compared to other types of Galactic pulsar. X-ray pulsar J1846-0258 can be in an early phase of anomalous X-ray pulsars and soft gamma repeaters if its average braking index is ~1.8–2.0. X-ray pulsar J1811-1925 must have a very large average braking index (~11) if this pulsar was formed by SN 386AD. This X-ray pulsar can be in an early phase of the evolution of the radio pulsars located in the region P ~ 50–150 ms and Ṗ ~ 10-14–10-16 ss -1 of the P–Ṗ diagram. X-ray/radio pulsar J0540-69 seems to be evolving in the direction to the dim isolated thermal neutron star region on the P–Ṗ diagram. Possible progenitors of different types of neutron star are also discussed.

scholarly journals The Case for no field decay from improved pulsar population studies

1996 ◽  
Vol 160 ◽  
pp. 47-48
Author(s):  
J.W. Hartman ◽  
F. Verbunt ◽  
D. Bhattacharya ◽  
R. Wijers
Keyword(s):  
Population Studies ◽  
Solar Neighborhood ◽  
Radio Pulsar ◽  
Population Synthesis ◽  
Radio Pulsars ◽  
Free Electrons ◽  
New Model ◽  
Full Report ◽  
The Galaxy ◽  
Field Decay

We perform radio pulsar population synthesis to study the evolution of the pulsar population. In doing this, we continue our earlier work on this subject (Bhattacharya et al. 1992). We have extended our work by 1) calculating orbits in the whole galaxy (the simulation of the observations however is still limited to the solar neighborhood), 2) using the high birth velocities of radio pulsars from Lyne & Lorimer (1994) and 3) implementing the new model by Taylor & Cordes (1993) of the distribution of free electrons in the galaxy. A full report of this work will be given in Hartman et al. (1996).

PULSAR KICKS AND DARK MATTER FROM A STERILE NEUTRINO

2005 ◽  
Vol 20 (06) ◽  
pp. 1148-1154 ◽  
Author(s):  
ALEXANDER KUSENKO
Keyword(s):  
Dark Matter ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Sterile Neutrino ◽  
Supernova Explosion ◽  
Radio Pulsars ◽  
X Ray ◽  
Gravitational Wave Detectors ◽  
Rule Out

The observed velocities of radio pulsars, which range in the hundreds kilometers per second, and many of which exceed 1000 km/s, are not explained by the standard physics of the supernova explosion. However, if a sterile neutrino with mass in the 1–20 keV range exists, it would be emitted asymmetrically from a cooling neutron star, which could give it a sufficient recoil to explain the pulsar motions. The same particle can be the cosmological dark mater. Future observations of X-ray telescopes and gravitational wave detectors can confirm or rule out this explanation.

scholarly journals The velocity distribution of young radio pulsars: simulating the observations

1996 ◽  
Vol 160 ◽  
pp. 53-54 ◽  
Author(s):  
J.W. Hartman
Keyword(s):  
Magnetic Field ◽  
Velocity Distribution ◽  
Proper Motion ◽  
Transverse Velocity ◽  
Radio Pulsar ◽  
Population Synthesis ◽  
Radio Pulsars ◽  
Full Report ◽  
Simulated Sample

Lyne & Lorimer (1994) argue that the velocities of young pulsars are much higher than was previously thought. However, recent radio pulsar population synthesis work by Hartman et al. (1996, these proceedings) shows that simulations that use a birth velocity distribution with more pulsars at low velocities, Phinney’s modification of the Paczyński (1990) distributiondescribes the observed magnetic field, period and luminosity distribution equally well as simulations that use the Lyne & Lorimer distribution.We use this radio pulsar population synthesis model to obtain the proper motion distribution of the simulated sample, and from that we calculate the transverse velocity distribution to compare it with the observed transverse velocity distribution. A full report of this work will be given in Hartman (1996).

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