scholarly journals Neutron Stars in Supernova Remnants

2000 ◽  
Vol 195 ◽  
pp. 91-93
Author(s):  
F. Pacini
Keyword(s):  
Neutron Stars ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
Shell Type ◽  
Cas A ◽  
The Crab Nebula

In the following, we shall briefly summarize some facts and ideas concerning the presence of neutron stars in supernova remnants. While sources similar to the Crab Nebula require the presence of a central energetic object, shell-type remnants such as Cas A are compatible with the presence of neutron stars releasing a weak relativistic wind.

scholarly journals Physical Processes and Parameters in the Magnetosphere of NP 0532

1971 ◽  
Vol 46 ◽  
pp. 394-406
Author(s):  
F. Pacini
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
General Relation ◽  
Energy Generation ◽  
Main Pulse ◽  
Physical Processes ◽  
X Ray ◽  
The Crab Nebula

The Crab Nebula pulsar conforms to the model of a rotating magnetised neutron star in the rate of energy generation and the exponent of the rotation law.It is suggested that the main pulse is due to electrons and the precursor to protons. Both must radiate in coherent bunches. Optical and X-ray radiation is by the synchrotron process.The wisps observed in the Nebula may represent the release of an instability storing about 1043 erg and 1047–48 particles.Finally, some considerations are made about the general relation between supernova remnants and rotating neutron stars.

scholarly journals Optical and UV Observations of Supernova Remnants

1996 ◽  
Vol 145 ◽  
pp. 381-389
Author(s):  
Robert A. Fesen
Keyword(s):  
Mass Loss ◽  
Proper Motion ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
Circumstellar Disk ◽  
Mantle Material ◽  
Cygnus Loop ◽  
Cas A ◽  
The Crab Nebula

Recent observations of the galactic supernova remnants the Crab Nebula, SN 1006, Cas A, and the Cygnus Loop are reviewed. New studies of the Crab Nebula suggest its progenitor may have had appreciable mass loss in the form of a circumstellar disk resulting in both a bipolar expansion and formation of the synchrotron ‘bays'. Unusually high proper motion knots near to and possibly directed away from the pulsar also have been reported. In the Cas A remnant, a NE jet of ejecta appears to be a plume of mantle material with expansion velocities up to 12000 km s-1 or nearly twice that seen in the main ejecta shell. HST observations of the sdOB star located behind SN 1006 indicate symmetrically expanding Fe II ejecta out to 8100 km s-1. Lastly, deep images of the Cygnus Loop reveal emission structures similar to those seen in 2D & 3D shocked cloud simulations.

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.

scholarly journals The Secular Behavior of X-Ray and Radio Emission from Supernova Remnants

1971 ◽  
Vol 46 ◽  
pp. 268-272
Author(s):  
Wallace H. Tucker
Keyword(s):  
Radio Emission ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
X Ray ◽  
Cas A ◽  
The Crab Nebula ◽  
Continuous Injection

Continuous injection models for the secular behavior of the radio and X-ray emission from supernova remnants are examined and compared with the observations. Among other things, it is concluded that (1) continuous injection probably occurs for at least 10 yr in every case and about 1000 yr in most supernova remnants, in which case the supernova remnants 3C392, W28, Pup A and IC443 should produce 1–10 keV X-ray fluxes ≈ 10-10 ergs/cm2-sec, and (2) the X-ray sources in the Crab Nebula, Cas A and Tycho can be explained in terms of a model wherein continuous injection occurs for 300 yr for the Crab Nebula, much less than 250 yr for Cas A and much longer than 400 yr for Tycho. Finally, it is shown that if Tycho and Cas A contain an X-ray star such as NP 0532, it is quite possible that the X-ray emission from those sources is predominantly due to the X-ray star.

scholarly journals A Newly-Recognised Galactic Supernova Remnant with Shell-Type and Filled-Centre Features

1988 ◽  
Vol 101 ◽  
pp. 347-350
Author(s):  
Peter J. Barnes ◽  
A.J. Turtle
Keyword(s):  
Spectral Index ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Crab Nebula ◽  
Dual Nature ◽  
Valuable Addition ◽  
Shell Type ◽  
The Crab Nebula ◽  
Galactic Object

While the number of galactic supernova remnants (SNRs) now known is fairly large (>150), the subset among these that are known to resemble the Crab Nebula is still distressingly small, about 15 or so (Green, 1984). Thus any object that can be unambiguously included in this exclusive club forms a valuable addition to our knowledge of this class. We report here observations of a newly recognised nonthermal galactic object, G18.94-l.06, having all the hallmarks of the classical shell-type SNRs, while also appearing to have a filled-centre component located inside the shell. Among the known Crab-like remnants, about one third show this dual nature (Green, 1984). This diagnosis of G18.94-1.06 is supported mainly by the variations in spectral index α (Sν∝ να) across the source, as seen between the two observation frequencies, 408 MHz and 5.0 GHz.

scholarly journals Structural Changes in Cas A, Tycho and Other Young Supernova Remnants

1983 ◽  
Vol 101 ◽  
pp. 37-47
Author(s):  
Richard G. Strom
Keyword(s):  
Supernova Remnants ◽  
Structural Changes ◽  
Crab Nebula ◽  
Optical Measurements ◽  
Radial Expansion ◽  
Simple Expansion ◽  
Cas A ◽  
The Crab Nebula

Structural changes have been found and investigated in a handful of young supernova remnants (SNR). The variations in the Crab Nebula (Trimble, 1968) have been known for some time. Here I am concerned with young shell remnants of which the best studied is Cas A. It is, like the Crab nebula, undergoing an overall radial expansion, although other forms of motion have also been observed. Simple expansion has been found in Tycho (3C10) and the remnant of SN 1006. Optical measurements of the remnant of Kepler's supernova (SN 1604), however, have failed to show motion of the magnitude expected from this relatively young SNR.

Neutron stars and cosmic-ray production

1968 ◽  
Vol 46 (10) ◽  
pp. S472-S475 ◽  
Author(s):  
D. B. Melrose ◽  
A. G. W. Cameron
Keyword(s):  
Neutron Stars ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Cosmic Ray ◽  
X Rays ◽  
Strong Point ◽  
Electrons And Ions ◽  
Supernova Explosions ◽  
The Crab Nebula

Recent investigations of the properties of neutron stars and of supernova explosions indicate that neutron stars should frequently be formed as supernova remnants. It now appears unlikely that any form of internal energy storage can play an important role in the production of X rays or cosmic rays. If mass infall onto a neutron star occurs at the upper limiting value allowed by radiation stresses, instabilities are likely to make the resulting mass infall, X-ray, gamma-ray, and cosmic-ray production very intermittent. It is shown that such a model may be able to account for many features of the Crab nebula: the energy input in electrons and ions, the character of the fast-moving light ripples or wisps, and the strong point source of ~50 MHz radiation.

scholarly journals Supernova Remnants Resembling the Crab Nebula

1983 ◽  
Vol 101 ◽  
pp. 299-320 ◽  
Author(s):  
K. W. Weiler
Keyword(s):  
Large Class ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
Origin And Evolution ◽  
Class C ◽  
The Individual ◽  
The Crab Nebula

While reviewing and systematizing the properties of the class of supernova remnants resembling the Crab Nebula it has been found that supernova remnants can be split into three morphological groups – Class S (shells), Class P (plerions), and Class C (combinations) – where the Class C objects appear to represent a new and especially interesting classification. In this overview, the identifying properties of all three classes are defined. Because the large Class S has been studied in detail many times previously, it is not discussed further here. For the smaller Classes P and C, the individual members and suspected members are presented and their properties reviewed. Finally, an origin and evolution for each class is suggested.

scholarly journals Searching for Compact Objects in Supernova Remnants: Initial Results

2004 ◽  
Vol 218 ◽  
pp. 123-126
Author(s):  
D. L. Kaplan ◽  
S. R. Kulkarni ◽  
D. A. Frail ◽  
B. M. Gaensler ◽  
P. O. Slane ◽  
...  
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Compact Objects ◽  
Cooling Curves ◽  
Limited Sample ◽  
Central Source ◽  
Systematic Effort ◽  
Cas A ◽  
Initial Results

Most astronomers now accept that stars more massive than about 9 M⊙ explode as supernovae and leave stellar remnants, either neutron stars or black holes. However, less than half of the SNRs within 5 kpc have identified central sources. Here, we discuss a systematic effort to search for compact central sources in the remaining 23 SNRs of this distance-limited sample. As the first part of this survey, we are able to state with some confidence that there are no associated central sources down to a level of one tenth of that of the Cas A central source, LX ≲ 1031 ergs s−1, in four SNRs (G093.3+6.9, G315.4−2.3, G084.2+0.8, and G127.1+0.5). We compare our limits with cooling curves for neutron stars and find that any putative neutron stars in these SNRs must be cooling faster than expected for traditional 1.35 M⊙ neutron stars.

scholarly journals The Galactic Sources G5.4-1.2 and G5.27-0.90

1987 ◽  
Vol 125 ◽  
pp. 129-129
Author(s):  
J.L. Caswell ◽  
M.J. Kesteven ◽  
R.F. Haynes ◽  
D.K. Milne ◽  
M.M. Komesaroff ◽  
...  
Keyword(s):  
Neutron Star ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
Stellar Core ◽  
Galactic Sources ◽  
The Crab Nebula

Long after a supernova event, the stellar core (neutron star) may continue to excite an extended remnant of ejecta surrounding it, as in the case of the Crab nebula. In contrast, the more common shell supernova remnants (SNRs) appear unaffected by any embedded neutron star.

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