scholarly journals Periodically repeating fast radio bursts: Lense–Thirring precession of a debris disk?

2020 ◽  
Vol 72 (4) ◽  
Author(s):  
Wen-Cong Chen
Keyword(s):  
Magnetic Field ◽  
Rotational Energy ◽  
Radio Bursts ◽  
Spin Period ◽  
Disk Mass ◽  
Debris Disk ◽  
The Magnetic Field ◽  
Normal Magnetic Field ◽  
Current Stage ◽  
Tilted Disk

Abstract Recently, repeating fast radio bursts (FRBs) with a period of PFRB = 16.35 ± 0.18 d from FRB 180916.J0158+65 were reported. It still remains controversial how such a periodicity might arise for this FRB. In this Letter, based on an assumption of a young pulsar surrounding by a debris disk, we attempt to diagnose whether Lense–Thirring precession of the disk on the emitter can produce the observed periodicity. Our calculations indicate that the Lense–Thirring effect of a tilted disk can result in a precession period of 16 d for a mass inflow rate of 0.5–1.5 × 1018 g s−1, a pulsar spin period of 1–20 ms, and an extremely low viscous parameter α = 10−8 in the disk. The disk mass and the magnetic field of the pulsar are also constrained to be ∼10−3 M⊙ and <2.5 × 1013 G. In our model, a new-born pulsar with normal magnetic field and millisecond period would successively experience the accretion and propeller phases, and is visible as a strong radio source in the current stage. The rotational energy of such a young neutron star can provide the observed radio bursting luminosity for 400 yr.

scholarly journals Analyzing the propagation of EUV waves and their connection with type II radio bursts by combining numerical simulations and multi-instrument observations

2020 ◽  
Vol 644 ◽  
pp. A90
Author(s):  
A. Koukras ◽  
C. Marqué ◽  
C. Downs ◽  
L. Dolla
Keyword(s):  
Magnetic Field ◽  
Wave Front ◽  
Ray Tracing ◽  
Radio Burst ◽  
Radio Bursts ◽  
Type Ii ◽  
Fast Mode ◽  
Type Ii Radio Bursts ◽  
The Magnetic Field ◽  
Burst Emission

Context. EUV (EIT) waves are wavelike disturbances of enhanced extreme ultraviolet (EUV) emission that propagate away from an eruptive active region across the solar disk. Recent years have seen much debate over their nature, with three main interpretations: the fast-mode magneto-hydrodynamic (MHD) wave, the apparent wave (reconfiguration of the magnetic field), and the hybrid wave (combination of the previous two). Aims. By studying the kinematics of EUV waves and their connection with type II radio bursts, we aim to examine the capability of the fast-mode interpretation to explain the observations, and to constrain the source locations of the type II radio burst emission. Methods. We propagate a fast-mode MHD wave numerically using a ray-tracing method and the WKB (Wentzel-Kramers-Brillouin) approximation. The wave is propagated in a static corona output by a global 3D MHD Coronal Model, which provides density, temperature, and Alfvén speed in the undisturbed coronal medium (before the eruption). We then compare the propagation of the computed wave front with the observed wave in EUV images (PROBA2/SWAP, SDO/AIA). Lastly, we use the frequency drift of the type II radio bursts to track the propagating shock wave, compare it with the simulated wave front at the same instant, and identify the wave vectors that best match the plasma density deduced from the radio emission. We apply this methodology for two EUV waves observed during SOL2017-04-03T14:20:00 and SOL2017-09-12T07:25:00. Results. The simulated wave front displays a good qualitative match with the observations for both events. Type II radio burst emission sources are tracked on the wave front all along its propagation. The wave vectors at the ray-path points that are characterized as sources of the type II radio burst emission are quasi-perpendicular to the magnetic field. Conclusions. We show that a simple ray-tracing model of the EUV wave is able to reproduce the observations and to provide insight into the physics of such waves. We provide supporting evidence that they are likely fast-mode MHD waves. We also narrow down the source region of the radio burst emission and show that different parts of the wave front are responsible for the type II radio burst emission at different times of the eruptive event.

scholarly journals Early neutron star evolution in high-mass X-ray binaries

2020 ◽  
Vol 494 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Wynn C G Ho ◽  
M J P Wijngaarden ◽  
Nils Andersson ◽  
Thomas M Tauris ◽  
F Haberl
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Thermal Emission ◽  
Equilibrium Phase ◽  
High Mass ◽  
X Ray ◽  
Spin Period ◽  
Long Duration ◽  
X Ray Binaries ◽  
The Magnetic Field

ABSTRACT The application of standard accretion theory to observations of X-ray binaries provides valuable insights into neutron star (NS) properties, such as their spin period and magnetic field. However, most studies concentrate on relatively old systems, where the NS is in its late propeller, accretor, or nearly spin equilibrium phase. Here, we use an analytic model from standard accretion theory to illustrate the evolution of high-mass X-ray binaries (HMXBs) early in their life. We show that a young NS is unlikely to be an accretor because of the long duration of ejector and propeller phases. We apply the model to the recently discovered ∼4000 yr old HMXB XMMU J051342.6−672412 and find that the system’s NS, with a tentative spin period of 4.4 s, cannot be in the accretor phase and has a magnetic field B > a few × 1013 G, which is comparable to the magnetic field of many older HMXBs and is much higher than the spin equilibrium inferred value of a few × 1011 G. The observed X-ray luminosity could be the result of thermal emission from a young cooling magnetic NS or a small amount of accretion that can occur in the propeller phase.

scholarly journals Modelling of spacecraft spin period during eclipse

2011 ◽  
Vol 29 (5) ◽  
pp. 875-882 ◽  
Author(s):  
E. Georgescu ◽  
F. Plaschke ◽  
U. Auster ◽  
K.-H. Fornaçon ◽  
H. U. Frey
Keyword(s):  
Magnetic Field ◽  
Heat Dissipation ◽  
Spin Model ◽  
Moment Of Inertia ◽  
Magnetic Field Direction ◽  
Spin Period ◽  
The Earth ◽  
Spacecraft Spin ◽  
The Moment ◽  
The Magnetic Field

Abstract. The majority of scientific satellites investigating the Earth magnetosphere are spin stabilized. The attitude information comes usually from a sun sensor and is missing in the umbra; hence, the accurate experimental determination of vector quantities is not possible during eclipses. The spin period of the spacecraft is generally not constant during these times because the moment of inertia changes due to heat dissipation. The temperature dependence of the moment of inertia for each spacecraft has a specific signature determined by its design and distribution of mass. We developed an "eclipse-spin" model for the spacecraft spin period behaviour using magnetic field vector measurements close to the Earth, where the magnetic field is dominated by the dipole field, and in the magnetospheric lobes, where the magnetic field direction is mostly constant. The modelled spin periods give us extraordinarily good results with accumulated phase deviations over one hour of less than 10 degrees. Using the eclipse spin model satellite experiments depending on correct spin phase information can deliver science data even during eclipses. Two applications for THEMIS B, one in the lobe and the other in the lunar wake, are presented.

Shock Drift Acceleration and Type II Solar Radio Bursts

1994 ◽  
Vol 11 (1) ◽  
pp. 21-24 ◽  
Author(s):  
Arthur G. Street ◽  
Lewis Ball ◽  
D. B. Melrose
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Shock Front ◽  
Solar Radio ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Type Ii Bursts ◽  
Herringbone Structure ◽  
The Magnetic Field

AbstractShock drift acceleration of the electrons which produce herringbone structure in type II bursts is considered. A non-coplanar component of the magnetic field within the shock front and an electric field across the shock are taken into account. A quantitative difficulty with shock drift acceleration is identified, and possible ways of overcoming the difficulty are outlined.

scholarly journals Electron Acceleration at Quasi-Parallel Shocks in The Solar Corona and Its Signature in Solar Type II Radio Bursts

1994 ◽  
Vol 142 ◽  
pp. 577-581
Author(s):  
G. Mann ◽  
H. Lühr
Keyword(s):  
Magnetic Field ◽  
Solar Corona ◽  
Radio Bursts ◽  
Type Ii ◽  
Radio Radiation ◽  
Earth’S Bow Shock ◽  
Type Ii Radio Bursts ◽  
Solar Type ◽  
Field Geometry ◽  
The Magnetic Field

AbstractRecently, strong large amplitude magnetic field structures (SLAMS) have been observed as a common phenomenon in the vicinity of the quasi-parallel region of Earth’s bow shock. A quasi-parallel shock transition can be considered as a patchwork of SLAMS. Using the data of the AMPTE/IRM magnetometer the properties of SLAMS are studied. Within SLAMS the magnetic field is strongly deformed and, thus, the magnetic field geometry is locally swung into a quasi-perpendicular regime. Therefore, electrons can locally be accelerated to high energies within SLAMS. Assuming that SLAMS also exist in the vicinity of supercritical, quasi-parallel shocks in the solar corona, they are able to generate radio radiation via the enhanced Langmuir turbulence excited by the accelerated electrons. Since SLAMS are connected with strong density enhancements, the aforementioned mechanism can explain the multiple-lane structure often occurred in solar Type II radio bursts.Subject headings: acceleration of particles — Earth — shock waves — Sun: corona — Sun: radio radiation

scholarly journals On spatial variations of magnetic field and superthermal electron distribution in cm-radio burst source

2008 ◽  
Vol 4 (S257) ◽  
pp. 353-356
Author(s):  
Leonid V. Yasnov ◽  
Marian Karlický
Keyword(s):  
Magnetic Field ◽  
Radio Burst ◽  
Electron Distribution ◽  
Impulsive Phase ◽  
Spatial Variations ◽  
Radio Bursts ◽  
Burst Source ◽  
Superthermal Electron ◽  
The Difference ◽  
The Magnetic Field

AbstractThe paper presents a new method of an estimation of spatial variations of the magnetic field and superthermal electron distribution in solar cm-radio burst sources. The method is based on the analysis of several burst spectra recorded in the different moments of time and on the minimization of the difference between the theoretical and observed radio fluxes. It is found that the measure of the spatial variations of superthermal electron distribution in the radio source is always greater than that for the magnetic field. In most cases this measure has a minimum at the impulsive phase of cm-radio bursts.

scholarly journals Seven pulsars in binary systems above the spin-up line

2012 ◽  
Vol 8 (S291) ◽  
pp. 462-464
Author(s):  
Y. Y. Pan ◽  
N. Wang
Keyword(s):  
Magnetic Field ◽  
Binary Systems ◽  
Spin Period ◽  
Binary Pulsars ◽  
Field Versus ◽  
Using Data ◽  
The Magnetic Field

AbstractUsing data from the ATNF pulsar catalogue, 186 binary pulsars are shown in the magnetic field versus spin period (B-P) diagram, and their relationship to the spin-up line is investigated. Generally speaking, pulsars in binary systems should be below the spin-up line when they get enough accretion mass from their companions. It is found that there are seven binary pulsars above the spin-up line. Based on the parameters of these seven binary systems, we describe possible reasons why they are above the spin-up line.

scholarly journals Fast Radio Bursts as crustal dynamical events induced by magnetic field evolution in young magnetars

2021 ◽  
Author(s):  
J.E. Horvath ◽  
M.G.B. de Avellar ◽  
L.S. Rocha ◽  
P.H.R.S. Moraes
Keyword(s):  
Magnetic Field ◽  
Gravitational Radiation ◽  
Soliton Solutions ◽  
Radio Bursts ◽  
X Rays ◽  
Simultaneous Emission ◽  
Field Evolution ◽  
Non Linear ◽  
The Magnetic Field

Abstract We revisit in this work a model for repeating Fast Radio Bursts based of the release of energy provoked by the magnetic field dynamics affecting a magnetar's crust. We address the basics of such a model by solving the propagation of the perturbation approximately, and quantify the energetics and the radiation by bunches of charges in the so-called {\it charge starved} region in the magnetosphere. The (almost) simultaneous emission of newly detected X-rays from SGR 1935+2154 is tentatively associated to a reconnection behind the propagation. The strength of $f$-mode gravitational radiation excited by the event is quantified, and more detailed studies of the non-linear (spiky) soliton solutions suggested.

CHARACTERISTIC AGE AND TRUE AGE OF PULSARS

2013 ◽  
Vol 23 ◽  
pp. 95-98
Author(s):  
LONG JIANG ◽  
CHENG-MIN ZHANG ◽  
ALI TANNI ◽  
HAI-HUI ZHAO
Keyword(s):  
Magnetic Field ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Millisecond Pulsar ◽  
Spin Period ◽  
Field Evolution ◽  
Period Derivative ◽  
The Difference ◽  
The Relationship ◽  
The Magnetic Field

Age of a pulsar is a useful parameter, but it is difficult to get the age from observation. We can only derive the characteristic age from the observed parameters: spin period (P) and period derivative (Ṗ). In this paper, we discussed the relationship between characteristic age and magnetic field of a pulsar. Monte Carlo simulation is also used to support the idea: it is useless to study the magnetic field evolution using characteristic age. From some observation evidences we get that: the characteristic age cannot be used as true age, especially for millisecond pulsar (MSP). The difference between them is also discussed. From the studying of breaking index and MSP's initial spin period (P0), we get the conclusion that: the problem cannot be resolved using different radiation models.

THE SPIN-UP OF ACCRETING NEUTRON STARS IN BINARY SYSTEMS

2011 ◽  
Vol 20 (10) ◽  
pp. 2019-2022
Author(s):  
J. WANG ◽  
C. M. ZHANG ◽  
Y. H. ZHAO
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Binary Systems ◽  
Initial Conditions ◽  
Initial Period ◽  
Spin Period ◽  
The Magnetic Field ◽  
Initial Magnetic Field

In binary systems, the rotation of neutron stars can be spun up by the accreted material, and at the same time the decay of their magnetic fields occur in the accretion phase. As a result, the spin period may arrive at a minimum of about 1.5 ms, corresponding to a bottom value of the magnetic field ~ 108 G. Taking the conditions: (i) initial magnetic field varying from 1011 G to 1013 G while setting period as 100 s, (ii) initial period as 1–100 s at B = 5 × 1012 G , we find that this minimum of spin period seems independent of these initial conditions.

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