On the Evolution of Supernova Remnants. Evolution of the Magnetic Field, Particles, Content, and Luminosity

1973 ◽  
Vol 186 ◽  
pp. 249 ◽  
Author(s):  
F. Pacini ◽  
M. Salvati
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
The Magnetic Field

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 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 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 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.

scholarly journals The modified equipartition calculation for supernova remnants with the spectral index α = 0.5

2012 ◽  
Vol 10 (H16) ◽  
pp. 398-398
Author(s):  
Dejan Urošević ◽  
Marko Z. Pavlović ◽  
Bojan Arbutina ◽  
Aleksandra Dobardžić
Keyword(s):  
Magnetic Field ◽  
Spectral Index ◽  
Analytical Method ◽  
Supernova Remnants ◽  
Spectral Indices ◽  
The Magnetic Field ◽  
Field Strengths

AbstractRecently, the modified equipartition calculation for supernova remnants (SNRs) has been derived by Arbutina et al. (2012). Their formulae can be used for SNRs with the spectral indices between 0.5 < α < 1. Here, by using approximately the same analytical method, we derive the equipartition formulae useful for SNRs with spectral index α=0.5. These formulae represent next step upgrade of Arbutina et al. (2012) derivation, because among 30 Galactic SNRs with available observational parameters for the equipartition calculation, 16 have spectral index α = 0.5. For these 16 Galactic SNRs we calculated the magnetic field strengths which are approximately 40 per cent higher than those calculated by using Pacholczyk (1970) equipartition and similar to those calculated by using Beck & Krause (2005) calculation.

scholarly journals Interaction of Jets with Clouds in Extragalactic Radio Sources

1994 ◽  
Vol 159 ◽  
pp. 346-346
Author(s):  
V. Fedorenko ◽  
A. Zentsova ◽  
T. J.-L. Courvoisier ◽  
S. Paltani
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Shock Acceleration ◽  
Stellar Winds ◽  
Radio Sources ◽  
Red Giants ◽  
Diffusive Shock Acceleration ◽  
Extragalactic Jets ◽  
The Magnetic Field ◽  
Very High

Several points indicate that extragalactic jets can interact with dense gaseous obstacles which occur on their ways. Examples of these interactions are the knotty structure of the radio and optical jet in M 87 and in other objects. These observations have been interpreted by Blandford & Königl in terms of collision of a jet with supernova remnants. We have reanalysed this idea taking into account new observations and improvements in the theory of diffusive shock acceleration. We find that the model requires a very high supernova birthrate (∼ 1 SN/year), which is not observed. It is more probable that the “obstacles” are formed by the stellar winds from the red giants. We estimate that the value of the magnetic field is ∼ 10−5 G in the interaction region (r=1kpc) (paper in preparation).

scholarly journals Evolution of magnetic field in a weakly relativistic counterstreaming inhomogeneous e−/e+ plasmas

2020 ◽  
Vol 38 (3) ◽  
pp. 181-187
Author(s):  
Sandeep Kumar ◽  
Y. K. Kim ◽  
T. Kang ◽  
Min Sup Hur ◽  
Moses Chung
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Inhomogeneous Plasma ◽  
Density Fluctuations ◽  
Weibel Instability ◽  
Thermal Anisotropy ◽  
Field Amplification ◽  
Plasma Distribution ◽  
The Magnetic Field

AbstractThe nonlinear evolution of electron Weibel instability in a symmetric, counterstream, unmagnetized electron–positron e−/e+ plasmas is studied by a 2D particle-in-cell (PIC) method. The magnetic field is produced and amplified by the Weibel instability, which extracts energy from the plasma anisotropy. A weakly relativistic drift velocity of 0.5c is considered for two counterstreaming e−/e+ plasma flows. Simulations show that in a homogeneous e−/e+ plasma distribution, the magnetic field amplifies exponentially in the linear regime and rapidly decays after saturation. However, in the case of inhomogeneous e−/e+ plasma distribution, the magnetic field re-amplifies at post-saturation. We also find that the amount of magnetic field amplification at post-saturation depends on the strength of the density inhomogeneity of the upstream plasma distribution. The temperature calculation shows that the finite thermal anisotropy exists in the case of an inhomogeneous plasma distribution which leads to the second-stage magnetic field amplification after the first saturation. Such density inhomogeneities are present in a variety of astrophysical sources: for example, in supernova remnants and gamma-ray bursts. Therefore, the present analysis is very useful in understanding these astrophysical sources, where anisotropic density fluctuations are very common in the downstream region of the relativistic shocks and the widely distributed magnetic field.

scholarly journals A review of maser polarization and magnetic fields

2007 ◽  
Vol 3 (S242) ◽  
pp. 37-46 ◽  
Author(s):  
W. H. T. Vlemmings
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Massive Star ◽  
Field Measurements ◽  
Star Forming ◽  
Physical Conditions ◽  
Evolved Stars ◽  
Star Forming Regions ◽  
Fields Of Study ◽  
The Magnetic Field

AbstractThrough polarization observations masers are unique probes of the magnetic field in a variety of different astronomical objects, with the different maser species tracing different physical conditions. In recent years maser polarization observations have provided insights in the magnetic field strength and morphology in, among others, the envelopes around evolved stars, Planetary Nebulae (PNe), massive star forming regions and supernova remnants. More recently, maser observations have even been used to determine the magnetic field in megamaser galaxies. This review will present an overview of maser polarization observations and magnetic field determinations of the last several years and discuss the implications of the magnetic field measurements for several important fields of study, such as aspherical PNe creation and massive star formation.

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