scholarly journals Interstellar Scintillations and Neutron Star Kinematics

1987 ◽  
Vol 125 ◽  
pp. 35-46
Author(s):  
J.M. Cordes
Keyword(s):  
Monte Carlo ◽  
Neutron Star ◽  
Neutron Stars ◽  
Binary Systems ◽  
Galactic Plane ◽  
Radio Pulsars ◽  
Population Monte Carlo ◽  
Interstellar Scintillation ◽  
Supernova Explosions ◽  
The Mean

The interstellar scintillation technique for measuring neutron star speeds is described and results are given for 71 radio pulsars. The mean transverse neutron star speed is 100 km s−1 and the distribution extends to 300 km s−1. The transverse speed correlates with the z velocity derived independently using distance from the galactic plane, consistent with most neutron stars having been born near the galactic plane. A correlation of transverse speed with the quantity PP ∝ (magnetic moment)2 is a general property of the neutron star population. Monte Carlo simulations of the progenitors of neutron stars show that the velocity distribution is inconsistent with the disruption of binary systems solely by symmetric supernova explosions. Either explosions are asymmetric or there are additional accelerations of neutron stars after their formation.

scholarly journals Impact of accretion on the statistics of neutron star masses

2012 ◽  
Vol 8 (S290) ◽  
pp. 195-196
Author(s):  
Z. Cheng ◽  
A. Taani ◽  
Y. H. Zhao
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Neutron Star ◽  
Neutron Stars ◽  
Binary Systems ◽  
Gaussian Function ◽  
Recycling Process ◽  
Mass Distributions ◽  
Spin Period ◽  
Boot Strap

AbstractWe have collected the parameter of 38 neutron stars (NSs) in binary systems with spin periods and measured masses. By adopting the Boot-strap method, we reproduced the procedure of mass calculated for each system separately, to determine the truly mass distribution of the NS that obtained from observation. We also applied the Monte-Carlo simulation and introduce the characteristic spin period 20 ms, in order to distinguish between millisecond pulsars (MSPs) and less recycled pulsars. The mass distributions of MSPs and the less recycled pulsars could be fitted by a Gaussian function as 1.45±0.42 M⊙ and 1.31±0.17 M⊙ (with 1σ) respectively. As such, the MSP masses are heavier than those in less recycled systems by factor of ~ 0.13M⊙, since the accretion effect during the recycling process.

scholarly journals Pulsars and Close Binary Systems

1971 ◽  
Vol 46 ◽  
pp. 273-278
Author(s):  
Virginia Trimble ◽  
Martin Rees
Keyword(s):  
Mass Transfer ◽  
Neutron Stars ◽  
Binary Systems ◽  
Alternative Explanation ◽  
Galactic Plane ◽  
Orbital Motion ◽  
Close Binary ◽  
Close Binaries ◽  
Close Binary Systems ◽  
Supernova Explosions

It is first considered what must happen if pulsars (i.e. neutron stars) are formed in close binary systems (CBS), and whether the resulting orbital motion and mass transfer should be observable. As this set of alternatives seems unlikely, there follow suggestions of how one might prevent the formation of neutron stars in close binaries. Finally, it is shown that ‘runaway’ pulsars with velocities larger than about 15 km/sec cannot be produced by isotropic supernova explosions within close binaries, and an alternative explanation is suggested for the observed correlation of periods of pulsars with their distances from the galactic plane.

Do neutron stars produce jets?

1986 ◽  
Vol 64 (4) ◽  
pp. 474-478 ◽  
Author(s):  
Eric D. Feigelson
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Binary Systems ◽  
Crab Nebula ◽  
Compact Object ◽  
Radio Pulsars ◽  
X Ray ◽  
The Crab Nebula ◽  
X Ray Binaries

The evidence for jets emanating from neutron stars is reviewed. Isolated radio pulsars do not appear to produce collimated outflows. A few supernova remnants, notably the Crab nebula, exhibit jetlike protrusions at their outer boundaries. These are probably "blowouts" of the plasma in the remnant rather than true jets from a neutron star. However, several cases of degenerate stars in X-ray binary systems do make jets. SS433 has twin precessing jets moving outward at v ~ 0.26c, and Sco X-1 has radio lobes with v ~ 0.0001c. Cyg X-3 appears to eject synchrotron plasmoids at high velocities. Other X-ray binaries associated with variable radio sources are discussed; some are interesting candidates for collimated outflow. G109.1-1.0 is an X-ray binary in a supernova remnant that may have radio or X-ray jets. It is not clear in all these cases, however, that the compact object is a neutron star and not a black hole or white dwarf.A tentative conclusion is reached that isolated neutron stars do not produce jets, but degenerate stars in accreting binary systems can. This suggests that the presence of an accretion disk, rather than the characteristics of an isolated pulsar's dipole magnetosphere, is critical in making collimated outflows.

MONTE CARLO SIMULATION OF NEUTRON STAR MASSES

2013 ◽  
Vol 23 ◽  
pp. 157-160
Author(s):  
ZHENG CHENG ◽  
CHENGMIN ZHANG ◽  
ALI TAANI
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Neutron Star ◽  
Confidence Level ◽  
White Dwarfs ◽  
Binary Systems ◽  
The Other ◽  
Radio Pulsars ◽  
Millisecond Pulsars ◽  
Spin Period

We perform a Monte Carlo simulation to investigate the distribution and evolution of 66 mass measured pulsars. We get the best fits to the distribution at 1.35 ± 0.27M⨀ (1σ confidence level). In addition, we notice bimodal distributions in 1.34 ± 0.15M⨀ and 1.48 ± 0.53M⨀, this can be led to the idea that radio pulsars in binary systems have recycled. Thus we divide the data according to the characteristic spin period into two groups, millisecond pulsars (MSPs), P Spin ≤ 20 ms and less recycled pulsars P Spin ≥ 20 ms , respectively. We show that the distributions of MSPs at 1.42 ± 0.36M⨀, and 1.32 ± 0.18M⨀ for less recycled pulsars. As such, the mass of MSPs are heavier than those in less recycled pulsars by ~ 0.1M⨀, since they accreting material from their companions. On the other hand, the formation of heavier pulsars from the accretion induced collapse of accreting white dwarfs, must be invoked.

scholarly journals Monte Carlo Simulations of Radio Pulsars and Their Progenitors

1987 ◽  
Vol 125 ◽  
pp. 408-408
Author(s):  
Rachel J. Dewey ◽  
James M. Cordes
Keyword(s):  
Neutron Star ◽  
Velocity Distribution ◽  
Neutron Stars ◽  
Binary Systems ◽  
Stellar Population ◽  
Main Sequence ◽  
Radio Pulsar ◽  
Close Binary ◽  
Radio Pulsars ◽  
Binary Pulsars

The formation of neutron stars in binary systems is often used to explain the nature of specific radio pulsars and characteristics of the pulsar population as a whole. We have investigated the extent to which such scenarios provide a self-consistent description of the pulsar population. Using a computer simulation, we modeled the evolution of the main sequence stellar population and compared the predicted neutron star population to the observed radio pulsar population, focusing our attention on the pulsar velocity distribution and the incidence of binary pulsars. These characteristics relate very directly to the binary nature of pulsar progenitors, and are not strongly dependent on models of pulsar magentic field and luminosity evolution.The need to reproduce both the high velocities typical of pulsars and the low incidence of binary pulsars strongly constrains the formation of pulsars in binary systems. Unless one assumes that virtually all pulsars originate in close binary systems, the observed velocity distribution cannot result from the disruption of binary systems by symmetric supernova explosions; some additional acceleration process (e.g. asymmetric supernova mass ejection or asymmetries in pulsar radiation) must act during or soon after a pulsar's formation. It is possible to reproduce the velocity distribution by assuming that all pulsars are born in binary systems with initial orbital periods less than about 30 years. However, the predicted incidence of binaries is then too large by more than an order of magnitude, unless one also assumes that the process of mass transfer from the primary to the secondary is almost always non-conservative, or that the minimum mass necessary for a stripped helium core to explode as a supernova is larger (over 4 M⊙) than currently believed. Further analyses of the radio pulsar population, the X-ray binary population and the abundances of elements ejected in supernovae should help determine which of these alternatives is most reasonble. Additional studies of the main sequence stellar population, accounting more accurately for evolutionary and observational selection effects, will reduce the uncertainties in modeling the formation of the neutron star population.It has also been suggested that the observed correlation between pulsar velocities and magnetic moments (see Cordes, these Proceedings) is induced by the differing evolutionary paths by which stars in binary systems form radio pulsars. Our simulation does not reproduce this correlation, and we do not find any paths likely to produce low velocity, low magnetic field neutron stars not in binary systems.We are submitting a full description of our model and results to The Astrophysical Journal.

scholarly journals Masses of Neutron Stars in X-ray Binary Systems

1981 ◽  
Vol 95 ◽  
pp. 353-356
Author(s):  
R. L. Kelley ◽  
S. Rappaport
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Binary Systems ◽  
Radio Pulsars ◽  
X Ray ◽  
The Masses

The masses of 6 neutron stars have now been established through studies of binary X-ray and radio pulsars. All of the masses are found to be consistent with, but not necessarily constrained to, the range 1.2–1.6 M⊙. In this talk we discuss the methods and assumptions used in determining the masses of neutron stars in binary X-ray pulsar systems. For other recent reviews of this subject, the reader is referred to Bahcall (1978), Rappaport and Joss (1981), and references therein. Neutron-star parameters may also be obtained from studies of X-ray bursts that result from thermonuclear flashes near the surface of an accreting neutron star (see Joss 1980 and references therein), which we will not discuss here.

scholarly journals A hot and fast ultra-stripped supernova that likely formed a compact neutron star binary

Science ◽  
2018 ◽  
Vol 362 (6411) ◽  
pp. 201-206 ◽  
Author(s):  
K. De ◽  
M. M. Kasliwal ◽  
E. O. Ofek ◽  
T. J. Moriya ◽  
J. Burke ◽  
...  
Keyword(s):  
Neutron Star ◽  
Kinetic Energy ◽  
Light Curve ◽  
Stellar Evolution ◽  
Binary Systems ◽  
Massive Stars ◽  
Compact Binary ◽  
Compact Binary Systems ◽  
Supernova Explosions ◽  
Star Binary

Compact neutron star binary systems are produced from binary massive stars through stellar evolution involving up to two supernova explosions. The final stages in the formation of these systems have not been directly observed. We report the discovery of iPTF 14gqr (SN 2014ft), a type Ic supernova with a fast-evolving light curve indicating an extremely low ejecta mass (≈0.2 solar masses) and low kinetic energy (≈2 × 1050ergs). Early photometry and spectroscopy reveal evidence of shock cooling of an extended helium-rich envelope, likely ejected in an intense pre-explosion mass-loss episode of the progenitor. Taken together, we interpret iPTF 14gqr as evidence for ultra-stripped supernovae that form neutron stars in compact binary systems.

scholarly journals The Galactic Pulsar Population and Neutron Star Birth

1987 ◽  
Vol 125 ◽  
pp. 67-78
Author(s):  
Ramesh Narayan
Keyword(s):  
Angular Momentum ◽  
Neutron Star ◽  
Binary Systems ◽  
Magnetic Coupling ◽  
Scale Height ◽  
High Magnetic Fields ◽  
Radio Pulsars ◽  
X Ray ◽  
The Galaxy ◽  
Low Mass

The radio pulsars in the Galaxy are found predominantly in the disk, with a scale height of several hundred parsecs. After allowing for pulsar velocities, the data are consistent with the hypothesis that single pulsars form from massive stellar progenitors. The number of active single pulsars in the Galaxy is ∼ 1.5 × 105, and their birthrate is 1 per ∼ 60 yrs. There is some evidence that many single pulsars, particularly those with high magnetic fields, are born spinning slowly, with initial periods ∼ 0.5–1s. This could imply an origin through binary “recycling” followed by orbit disruption, or might suggest that the pre-supernova stellar core efficiently loses angular momentum to the envelope through magnetic coupling. The birthrate of binary radio pulsars, particularly of the millisecond variety, seems to be much larger than previous estimates, and might suggest that these systems do not originate in low mass X-ray binary systems.

scholarly journals A search for pulsars in subdwarf B binary systems and discovery of giant-pulse emitting PSR J0533−4524

2020 ◽  
Vol 492 (4) ◽  
pp. 4825-4836 ◽  
Author(s):  
L C Oostrum ◽  
J van Leeuwen ◽  
Y Maan ◽  
T Coenen ◽  
C H Ishwara-Chandra
Keyword(s):  
Neutron Star ◽  
Binary Systems ◽  
Mass Range ◽  
Radio Pulsars ◽  
Average Sensitivity ◽  
Fundamental Physics ◽  
Giant Pulses ◽  
Periodic Signals ◽  
Low Magnetic Field

ABSTRACT 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 identified, allowing us to perform a targeted search for MSPs within these systems. Six sdBs with companions in the neutron star mass range, as determined from their optical light curves, were observed with the Green Bank and Westerbork radio telescopes. The data were searched for periodic signals as well as single pulses. No radio pulsations from sdB systems were detected, down to an average sensitivity limit of $0.11\,$mJy. We did, however, discover a pulsar in the field of sdB HE0532−4503. Follow-up observations with the Giant Metrewave Radio Telescope showed that this pulsar, J0533−4524, is not spatially coincident with the sdB system. The pulsar has a relatively low magnetic field but still emits giant pulses. We place an upper limit of three to the number of radio pulsars in the six sdB systems. The non-detections may be explained by a combination of the MSP beaming fraction, luminosity, and a recycling fraction <0.5. Alternatively, the assumption of corotation between the MSP and sdB may break down, which implies the systems are more edge-on than previously thought. This would shift the predicted companion masses into the white dwarf range. It would also explain the relative lack of edge-on sdB systems with massive companions.

scholarly journals Astrometric observations of neutron stars

2012 ◽  
Vol 8 (S289) ◽  
pp. 82-82
Author(s):  
Shami Chatterjee
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Gamma Ray ◽  
Radio Pulse ◽  
Focal Plane Arrays ◽  
Yield Model ◽  
Long Baseline ◽  
Wide Range ◽  
Pulse Timing ◽  
Supernova Explosions

AbstractAstrometric observations of neutron stars have been conducted with a variety of techniques and over a wide range of wavelengths, ranging from radio-pulse timing and Very Long Baseline Interferometry to optical and X-ray imaging. Here I review the techniques and scientific goals behind recent high-precision neutron-star astrometry. Such measurements can yield model-independent distances and velocities that can be exploited, for example, to locate neutron-star birth sites, establish reference-frame ties, model the Galactic electron-density distribution, and constrain the astrophysics of supernova explosions. Recently, the Fermi gamma-ray space telescope has identified several highly luminous recycled pulsars, and precise measurement of their distances is of paramount importance to understand their energetics and astrophysics. The ongoing science returns from precision astrometry will continue in the long term with improvements in technology such as focal-plane arrays and synergies with new telescopes such as Gaia and the Square Kilometer Array.

Sign in / Sign up

Export Citation Format

Share Document