scholarly journals Nova GK Persei – A Miniature Supernova Remnant?

1988 ◽  
Vol 101 ◽  
pp. 47-50
Author(s):  
E.R. Seaquist ◽  
D.A. Frail ◽  
M.F. Bode ◽  
J.A. Roberts ◽  
D.C.B. Whittet ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Synchrotron Radiation ◽  
Strong Evidence ◽  
White Dwarf ◽  
Planetary Nebula ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Optical Images ◽  
Ambient Gas ◽  
The Magnetic Field

AbstractWe present radio and optical images of the shell-like remnant of the 1901 outburst of Nova GK Persei. The behaviour of this object is remarkably similar to supernova remnants. The synchrotron radiation-emitting shell is polarized with the magnetic field oriented radially, as in young SNR’s. This similarity plus extensive data we have acquired on the expansion and the interstellar environment of GK Per indicate that the nova shell is colliding with ambient gas whose density is substantially higher than the ISM.Furthermore, there is strong evidence that the ambient gas is circumstellar rather than interstellar, and that this material is the shell of an ancient planetary nebula associated with the white dwarf companion of GK Per.

scholarly journals Trans-Alfvénic magnetohydrodynamic turbulence in the vicinity of supernova remnant Cassiopeia-A shocks

2020 ◽  
Vol 498 (1) ◽  
pp. 1093-1100
Author(s):  
Pavan Kumar Vishwakarma ◽  
Jais Kumar
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Magnetic Energy ◽  
Energy Spectra ◽  
Magnetohydrodynamic Turbulence ◽  
Cassiopeia A ◽  
Point Correlation ◽  
Frequency Observation ◽  
The Magnetic Field

ABSTRACT Statistics of the magnetic field disturbances in supernova remnants (SNRs) can be accessed using the second-order correlation function of the synchrotron intensities. Here we measure the magnetic energy spectra in the supernova remnant Cassiopeia-A by two-point correlation of the synchrotron intensities, using a recently developed unbiased method. The measured magnetic energy spectra in the vicinity of supernova remnant shocks are found to be a 2/3 power law over the decade of range scales, showing the developed trans-Alfvénic magnetohydrodynamic turbulence. Our results are globally consistent with the theoretical prediction of trans-Alfvénic Mach number in developed magnetohydrodynamic turbulence and can be explained by amplification of the magnetic field in the vicinity of SNR shocks. The magnetic energy spectra predict SNR Cassiopeia-A to have an additional subshock in the radio frequency observation along with forward and reverse shocks, with a radial window of the amplified magnetic field of ∼ 0.115 pc near the shocks.

Circularly Polarized Synchrotron Radiation in Dipolar Magnetic Fields with Application to the Planet Jupiter

1969 ◽  
Vol 1 (6) ◽  
pp. 274-276 ◽  
Author(s):  
L. J. Gleeson ◽  
M. P. C. Legg ◽  
K. C. Westfold
Keyword(s):  
Magnetic Field ◽  
Synchrotron Radiation ◽  
Magnetic Fields ◽  
Linear Polarization ◽  
Thin Shell ◽  
Total Radiation ◽  
Circularly Polarized ◽  
Preliminary Account ◽  
The Magnetic Field

This paper is a preliminary account of the calculation of the circularly polarized synchrotron radiation received from a distribution of electricallycharged particles confined to a thin shell in the magnetic field of a dipole. Calculations of the total radiation and the degree of linear polarization have previously been carried out, and these calculations are duplicated in part.

scholarly journals Galactic Center threads as nuclear magnetohydrodynamic waves

2020 ◽  
Vol 72 (2) ◽  
Author(s):  
Yoshiaki Sofue
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Galactic Center ◽  
Mhd Waves ◽  
Fast Mode ◽  
Magnetohydrodynamic Waves ◽  
Compression Waves ◽  
Sgr A ◽  
The Waves ◽  
The Magnetic Field

Abstract Propagation of fast-mode magnetohydrodynamic (MHD) compression waves is traced in the Galactic Center with a poloidal magnetic cylinder. MHD waves ejected from the nucleus are reflected and guided along the magnetic field, exhibiting vertically stretched fronts. The radio threads and non-thermal filaments are explained as due to tangential views of the waves driven by sporadic activity in Sgr A$^*$, or by multiple supernovae. In the latter case, the threads could be extremely deformed relics of old supernova remnants exploded in the nucleus.

scholarly journals Mathematical Theory of Cylindrical Isothermal Blast Waves in a Magnetic Field

1981 ◽  
Vol 34 (3) ◽  
pp. 279 ◽  
Author(s):  
I Lerche
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Magnetic Pressure ◽  
Blast Waves ◽  
Physical Domain ◽  
Fluid Flow Velocity ◽  
Magnetic Tension ◽  
Self Similar ◽  
The Magnetic Field ◽  
Similar Flows

An investigation is made of the self-similar flow behind a cylindrical blast wave from a line explosion (situated on r = 0, using conventional cylindrical coordinates r, 4>, z) in a medium whose density and magnetic field both vary as r -w ahead of the blast front, with the assumption that the flow is isothermal. The magnetic field can have components in both the azimuthal B(jJ and longitudinal B, directions. It is found that: (i) For B(jJ =f:. 0 =f:. B, a continuous single-valued solution with a velocity field representing outflow of material away from the line of explosion does not exist for OJ OJ > 0 the governing equation possesses a set of movable critical points. In this case it is shown that the fluid flow velocity is bracketed between two curves and that the asymptotes of the velocity curve on the shock are intersected by, or are tangent to, the two curves. Thus a solution always exists in the physical domain r ~ o. The overall conclusion from the investigation is that the behaviour of isothermal blast waves in the presence of an ambient magnetic field differs substantially from the behaviour calculated for no magnetic field. These results have an impact upon previous applications of the theory of self-similar flows to evolving supernova remnants without allowance for the dynamical influence of magnetic pressure and magnetic tension.

scholarly journals Secondary-electron radiation accompanying hadronic GeV–TeV gamma-rays from supernova remnants

2020 ◽  
Vol 492 (3) ◽  
pp. 4246-4253 ◽  
Author(s):  
Yan Huang ◽  
Zhuo Li ◽  
Wei Wang ◽  
Xiaohong Zhao
Keyword(s):  
Synchrotron Radiation ◽  
Gamma Rays ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Far Infrared ◽  
Hadronic Interactions ◽  
Electrons And Positrons ◽  
Tev Gamma Rays ◽  
The Magnetic Field

ABSTRACT The synchrotron radiation from secondary electrons and positrons (SEPs) generated by hadronic interactions in the shock of supernova remnant (SNR) could be a distinct evidence of cosmic ray (CR) production in SNR shocks. Here, we provide a method where the observed gamma-ray flux from SNRs, created by pion decays, is directly used to derive the SEP distribution and hence the synchrotron spectrum. We apply the method to three gamma-ray bright SNRs. In the young SNR RX J1713.7−3946, if the observed GeV−TeV gamma-rays are of hadronic origin and the magnetic field in the SNR shock is B ≳ 0.5 mG, the SEPs may produce a spectral bump at 10−5–10−2 eV, exceeding the predicted synchrotron component of the leptonic model, and a soft spectral tail at ≳100 keV, distinct from the hard spectral slope in the leptonic model. In the middle-aged SNRs IC443 and W44, if the observed gamma-rays are of hadronic origin, the SEP synchrotron radiation with B ∼ 400–500 μG can well account for the observed radio flux and spectral slopes, supporting the hadronic origin of gamma-rays. Future microwave to far-infrared and hard X-ray (>100keV) observations are encouraged to constraining the SEP radiation and the gamma-ray origin in SNRs.

scholarly journals The Chandrasekhar Mass of A Gravitating Electron Crystal

1994 ◽  
Vol 147 ◽  
pp. 565-570
Author(s):  
D. Engelhardt ◽  
I. Bues
Keyword(s):  
Magnetic Field ◽  
Density Matrix ◽  
White Dwarf ◽  
Matrix Formalism ◽  
Plasma Zone ◽  
Isothermal Model ◽  
Fermi Function ◽  
Density Matrix Formalism ◽  
The Magnetic Field ◽  
Electron Crystal

AbstractThe internal structure of a white dwarf may be changed by a strong magnetic field. A local model of the electrons is constructed within a thermal density matrix formalism, essentially a Heisenberg magnetism model. This results in a matrix Fermi function which is used to construct an isothermal model of the electron crystal. The central density of the crystal is 108kg/m3 independent of the magnetic field within the plasma and therefore lower than the relativistic density, whereas this density is constant until the Fermi momentum x f = 0.3 * me * c. Chandrasekhar masses up to 1.44 * 1.4M0 are possible for polarizations of the plasma zone lower than 0.5, if the temperature is close to the Curie point, whereas the crystal itself destabilizes the white dwarf dependent on temperature.

scholarly journals Probing interstellar magnetic fields with Supernova remnants

2008 ◽  
Vol 4 (S259) ◽  
pp. 75-80 ◽  
Author(s):  
Roland Kothes ◽  
Jo-Anne Brown
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Supernova Remnants ◽  
Large Scale ◽  
Galactic Plane ◽  
Field Configuration ◽  
Large Scale Magnetic Field ◽  
Rotation Measure ◽  
Field Lines ◽  
The Magnetic Field

AbstractAs Supernova remnants expand, their shock waves are freezing in and compressing the magnetic field lines they encounter; consequently we can use Supernova remnants as magnifying glasses for their ambient magnetic fields. We will describe a simple model to determine emission, polarization, and rotation measure characteristics of adiabatically expanding Supernova remnants and how we can exploit this model to gain information about the large scale magnetic field in our Galaxy. We will give two examples: The SNR DA530, which is located high above the Galactic plane, reveals information about the magnetic field in the halo of our Galaxy. The SNR G182.4+4.3 is located close to the anti-centre of our Galaxy and reveals the most probable direction where the large-scale magnetic field is perpendicular to the line of sight. This may help to decide on the large-scale magnetic field configuration of our Galaxy. But more observations of SNRs are needed.

scholarly journals Magnetic Field in the Proto-Planetary Nebula OH17.7–2.0

2003 ◽  
Vol 209 ◽  
pp. 143-144
Author(s):  
Indra Bains ◽  
Tim Gledhill ◽  
Jeremy Yates ◽  
Anita Richards
Keyword(s):  
Magnetic Field ◽  
Planetary Nebula ◽  
Field Structure ◽  
Radio Observations ◽  
Magnetic Field Structure ◽  
First Results ◽  
The Magnetic Field

We have used radio observations of OH masers in proto-planetary nebula (PPN) candidates to probe the magnetic field structure of these objects. Here we present the first results of our study, concerning the PPN OH17.7–2.0.

scholarly journals Polarization Observations of Supernova Remnants

1974 ◽  
Vol 60 ◽  
pp. 335-346 ◽  
Author(s):  
D. K. Milne ◽  
John R. Dickel
Keyword(s):  
Magnetic Field ◽  
Faraday Rotation ◽  
Supernova Remnants ◽  
Power Structure ◽  
Total Power ◽  
Field Patterns ◽  
Angular Extent ◽  
The Individual ◽  
The Magnetic Field ◽  
Galactic Background

Polarization and total power at 5000 MHz and 2700 MHz have been obtained for 30 supernova remnants (SNR) using the 64-m radio telescope at Parkes. This large sample includes a range of SNR from the young bright objects (such as Kepler's SNR) through the old faint sources such as MSH 14-63. Among the old remnants, the individual SNR have very varied properties, but several general conclusions emerge from our study. (1) In many cases, the polarization of the galactic background is as strong as that of the SNR and can vary significantly over the angular extent of the SNR. (2) The Faraday rotation is generally small and varies quite uniformly across the source. (3) The magnetic field patterns, although associated with the SNR, do not show any particularly characteristic pattern or relations to the total-power structure of the source.

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