scholarly journals Radio emission from a pulsar’s magnetic pole revealed by general relativity

Science ◽  
2019 ◽  
Vol 365 (6457) ◽  
pp. 1013-1017 ◽  
Author(s):  
Gregory Desvignes ◽  
Michael Kramer ◽  
Kejia Lee ◽  
Joeri van Leeuwen ◽  
Ingrid Stairs ◽  
...  
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Radio Emission ◽  
Neutron Stars ◽  
Geometrical Model ◽  
Spin Axis ◽  
Magnetic Pole ◽  
Polarization Model ◽  
Binary Pulsars ◽  
Relativistic Treatment

Binary pulsars are affected by general relativity (GR), causing the spin axis of each pulsar to precess. We present polarimetric radio observations of the pulsar PSR J1906+0746 that demonstrate the validity of the geometrical model of pulsar polarization. We reconstruct the (sky-projected) polarization emission map over the pulsar’s magnetic pole and predict the disappearance of the detectable emission by 2028. Two tests of GR are performed using this system, including the spin precession for strongly self-gravitating bodies. We constrain the relativistic treatment of the pulsar polarization model and measure the pulsar beaming fraction, with implications for the population of neutron stars and the expected rate of neutron star mergers.

General relativity and neutron stars

2016 ◽  
Vol 31 (02n03) ◽  
pp. 1641017
Author(s):  
D. G. Yakovlev
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Mass Measurements ◽  
Einstein Theory ◽  
Superdense Matter ◽  
Compact Binaries ◽  
Star Models ◽  
Neutron Star Mass

General Relativity affects all major aspects of neutron star structure and evolution including radiation from the surface, neutron star models, evolution in compact binaries. It is widely used for neutron star mass measurements and for studying properties of superdense matter in neutron stars. Observations of neutron stars help testing General Relativity and planning gravitational wave experiments. No deviations from Einstein Theory of Gravity have been detected so far from observations of neutron stars.

scholarly journals Binary pulsars and tests of general relativity

2009 ◽  
Vol 5 (S261) ◽  
pp. 218-227 ◽  
Author(s):  
I. H. Stairs
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
White Dwarf ◽  
Strong Field ◽  
Binding Energies ◽  
Tests Of General Relativity ◽  
Binary Pulsars ◽  
The Difference

AbstractBinary pulsars are a valuable laboratory for gravitational experiments. Double-neutron-star systems such as the double pulsar provide the most stringent tests of strong-field gravity available to date, while pulsars with white-dwarf companions constrain departures from general relativity based on the difference in gravitational binding energies in the two stars. Future observations may open up entirely new tests of the predictions of general relativity.

scholarly journals The MAVERIC Survey: Variable Jet-accretion Coupling in Luminous Accreting Neutron Stars in Galactic Globular Clusters

2021 ◽  
Vol 923 (1) ◽  
pp. 88
Author(s):  
Teresa Panurach ◽  
Jay Strader ◽  
Arash Bahramian ◽  
Laura Chomiuk ◽  
James C. A. Miller-Jones ◽  
...  
Keyword(s):  
Black Holes ◽  
Neutron Star ◽  
Radio Emission ◽  
Neutron Stars ◽  
Globular Clusters ◽  
Radio Continuum ◽  
X Rays ◽  
X Ray ◽  
Galactic Globular Clusters ◽  
X Ray Binaries

Abstract Accreting neutron stars in low-mass X-ray binaries show outflows—and sometimes jets—in the general manner of accreting black holes. However, the quantitative link between the accretion flow (traced by X-rays) and outflows and/or jets (traced by radio emission) is much less well understood for neutron stars than for black holes, other than the general observation that neutron stars are fainter in the radio at a given X-ray luminosity. We use data from the deep MAVERIC radio continuum survey of Galactic globular clusters for a systematic radio and X-ray study of six luminous (L X > 1034 erg s−1) persistent neutron star X-ray binaries in our survey, as well as two other transient systems also captured by our data. We find that these neutron star X-ray binaries show an even larger range in radio luminosity than previously observed. In particular, in quiescence at L X ∼ 3 × 1034 erg s−1, the confirmed neutron star binary GRS 1747–312 in Terzan 6 sits near the upper envelope of the black hole radio/X-ray correlation, and the persistently accreting neutron star systems AC 211 (in M15) and X1850–087 (in NGC 6712) show unusual radio variability and luminous radio emission. We interpret AC 211 as an obscured “Z source” that is accreting at close to the Eddington limit, while the properties of X1850–087 are difficult to explain, and motivate future coordinated radio and X-ray observations. Overall, our results show that neutron stars do not follow a single relation between inflow and outflow, and confirm that their accretion dynamics are more complex than for black holes.

scholarly journals Recent Observations of PSR B1534+12

2001 ◽  
Vol 205 ◽  
pp. 408-409
Author(s):  
I.H. Stairs ◽  
S.E. Thorsett ◽  
J.H. Taylor ◽  
Z. Arzoumanian
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Spin Axis ◽  
Pulse Profile ◽  
High Quality ◽  
Orbital Parameters ◽  
General Relativistic ◽  
Star Binary

We present the results of recent Arecibo observations of the relativistic double-neutron-star binary PSR B1534+12. The timing solution includes measurements of five post-Keplerian orbital parameters, whose values agree well with the predictions of general relativity. The observations show that the pulse profile is evolving secularly at both 1400 MHz and 430 MHz. This effect is similar to that seen in PSR B1913+16, and is almost certainly due to general relativistic precession of the pulsar's spin axis. We also present high-quality polarimetric profiles at both observing frequencies.

Black Hole, Neutron Star and Numerical Relativity

2021 ◽  
Vol 30 (6) ◽  
pp. 7-13
Author(s):  
Jinho KIM
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Neutron Star ◽  
Neutron Stars ◽  
Numerical Method ◽  
High Velocity ◽  
Compact Objects ◽  
Compact Stars ◽  
Speed Of Light

Compact stars, e.g., black holes and neutron stars, are the most energetic objects in astrophysics. These objects are accompanied by extremely strong gravity and a high velocity, which approaches the speed of light. Therefore, compact objects should be dealt with in Einstein’s relativity. This article will briefly introduce a numerical method that will allow us to obtain general solutions in general relativity. Several applications using numerical relativistic simulations will also be presented.

Pan Galactic Gargle Blaster

2019 ◽  
pp. 132-137
Author(s):  
Nicholas Mee
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Neutron Stars ◽  
Gravitational Waves ◽  
Gamma Ray ◽  
Great Accuracy ◽  
Gamma Ray Bursts ◽  
Tests Of General Relativity ◽  
Binary Neutron Star

The sources of short gamma ray bursts (GRBs) have been identified with neutron star merger events. Hulse and Taylor discovered the first binary neutron star in 1974. By monitoring the pulsar in this system the orbital characteristics of the system have been determined with great accuracy. This has led to tests of general relativity, including the first confirmation of the existence of gravitational waves. The emission of this radiation is gradually bringing the two neutron stars together. They will collide and merge in about 300 million years.

scholarly journals Evolving neutron star+helium star systems to intermediate-mass binary pulsars

2019 ◽  
Vol 490 (1) ◽  
pp. 752-757 ◽  
Author(s):  
W Tang ◽  
D Liu ◽  
B Wang
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Accretion Rate ◽  
Intermediate Mass ◽  
X Ray ◽  
Binary Pulsars ◽  
Orbital Periods ◽  
Helium Star ◽  
X Ray Binaries ◽  
Better Than

ABSTRACT Intermediate-mass binary pulsars (IMBPs) are composed of neutron stars (NSs) and CO/ONe white dwarfs (WDs). It is generally suggested that IMBPs evolve from intermediate-mass X-ray binaries (IMXBs). However, this scenario is difficult to explain the formation of IMBPs with orbital periods (Porb) less than 3 d. It has recently been proposed that a system consisting of an NS and a helium (He) star can form IMBPs with Porb less than 3 d (known as the NS+He star scenario), but previous works can only cover a few observed sources with short orbital periods. We aim to investigate the NS+He star scenario by adopting different descriptions of the Eddington accretion rate ($\skew4\dot{M}_{\rm Edd}$) for NSs and different NS masses (MNS) varying from $1.10$ to $1.80\, \rm M_{\odot }$. Our results can cover most of the observed IMBPs with short orbital periods and almost half of the observed IMBPs with long orbital periods. We found that $\skew4\dot{M}_{\rm Edd}$ ∝ MNS−1/3 could match the observations better than a specific value for all NSs. We also found that the final spin periods of NSs slightly decrease with the initial MNS. The observed parameters of PSR J0621+1002, which is one of the well-observed IMBPs whose pulsar mass has been precisely measured, can be reproduced by this work.

scholarly journals Secondary Components of Binary Pulsars & Magnetic Field Decay in Neutron Stars

1987 ◽  
Vol 125 ◽  
pp. 407-407
Author(s):  
Shrinivas R. Kulkarni
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Neutron Stars ◽  
White Dwarf ◽  
Optical Counterpart ◽  
Surface Magnetic Field ◽  
Binary Pulsars ◽  
Field Decay

We report the discovery of white dwarf secondaries in 0655+64 and 0820+02 systems. In the 2303+46 system, we do not find any optical counterpart suggesting that the companion is another neutron star. The existence of a cool and therefore old white dwarf in the 0655+64 system implies that the surface magnetic field of neutron stars stops decaying beyond some value(s) of field strength.

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 Recent LIGO-Virgo discoveries

2021 ◽  
pp. 2130010
Author(s):  
Maximiliano Isi
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Neutron Star ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Compact Objects ◽  
Tests Of General Relativity ◽  
Mass Gap ◽  
Cosmic History

The LIGO and Virgo gravitational-wave detectors carried out the first half of their third observing run from April through October 2019. During this period, they detected 39 new signals from the coalescence of black holes or neutron stars, more than quadrupling the total number of detected events. These detections included some unprecedented sources, like a pair of black holes with unequal masses (GW190412), a massive pair of neutron stars (GW190425), a black hole potentially in the supernova pair-instability mass gap (GW190521), and either the lightest black hole or the heaviest neutron star known to date (GW190814). Collectively, the full set of signals provided astrophysically valuable information about the distributions of compact objects and their evolution throughout cosmic history. It also enabled more constraining and diverse tests of general relativity, including new probes of the fundamental nature of black holes. This review summarizes the highlights of these results and their implications.

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