On Interpretations of Observed Radio Properties of Cas A

1979 ◽  
Vol 3 (5) ◽  
pp. 347-348
Author(s):  
I. Lerche† ◽  
J. L. Caswell
Keyword(s):  
Radio Emission ◽  
Surface Brightness ◽  
Supernova Remnant ◽  
Detailed Comparison ◽  
Cas A

Cas A has a radio surface brightness much higher (by a factor of about 100) than that of any other galactic supernova remnant (SNR) and is probably the youngest (≤ 300 yr). It therefore provides unique information on young remnants, but this very uniqueness makes it hazardous to treat Cas A as a typical remnant. However, because it (i) shows a clearly defined shell of radio emission of much the same type as older remnants, and (ii) lies approximately on the extrapolation of the Σ.-D (surface brightness-diameter) relationship derived for older remnants (Clark and Caswell 1976); Caswell and Lerche 1979a), detailed comparison with older remnants seems appropriate.

scholarly journals VLA Observations of Sgr A

1983 ◽  
Vol 101 ◽  
pp. 65-69
Author(s):  
W. M. Goss ◽  
U. J. Schwarz ◽  
R. D. Ekers ◽  
J. H. van Gorkom
Keyword(s):  
Surface Brightness ◽  
Supernova Remnant ◽  
Crab Nebula ◽  
Galactic Centre ◽  
Thermal Source ◽  
Very Large Array ◽  
Sgr A ◽  
Cas A ◽  
Relationship Of ◽  
The Crab Nebula

The radio source Sgr A has been mapped with the Very Large Array (VLA) at 6 and 20 cm with an angular resolution of 5″ x 8″ arc. In agreement with the earlier “WORST” map, the non-thermal source Sgr A East shows a shell structure, while the thermal source Sgr A West shows a spiral-like morphology. We suggest that Sgr A East is a supernova remnant (SNR) near the galactic centre. Its surface brightness is the third largest in our galaxy after Cas A and the Crab Nebula. The diameter is 9 pc and the source fits the surface-brightness diameter relationship of Clark and Caswell (1976) if a distance of 10 kpc is assumed.

scholarly journals Radio Supernovae

1996 ◽  
Vol 145 ◽  
pp. 283-297 ◽  
Author(s):  
Kurt W. Weiler ◽  
Schuyler D. Van Dyk ◽  
Richard A. Sramek ◽  
Nino Panagia
Keyword(s):  
Radio Emission ◽  
Supernova Remnant ◽  
Optical Emission ◽  
Late Time ◽  
Powerful Radio ◽  
Distance Measurements ◽  
X Ray ◽  
Circumstellar Material ◽  
Cas A ◽  
Progenitor Stars

Radio observations have shown that some supernovae are powerful radio emitters which increase rapidly in brightness to radio luminosities which are hundreds to thousands of times greater than even the brightest known supernova remnant, Cas A. They then fade over a period of weeks, months, or years. This radio emission has been found to provide important information about the nature of the progenitor stars, their mass loss rates, and the circumstellar material surrounding them. RSN observations may also offer the possibility of extragalactic distance measurements and the presence of radio emission appears to be indicator of strong x-ray emission and late time optical emission.

scholarly journals Some Observations of Shell-type Galactic Radio Sources

1967 ◽  
Vol 20 (3) ◽  
pp. 297 ◽  
Author(s):  
ER Hill
Keyword(s):  
Radio Emission ◽  
Spherical Symmetry ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Milky Way ◽  
Radio Sources ◽  
Radio Observations ◽  
Shell Type ◽  
Rosette Nebula ◽  
Galactic Radio

Radio evidence for two new supernova remnants in the Southern Milky Way is presented. Some new observations of the known supernova remnant, source 1439-62, and of the Rosette nebula, a shell source but not a supernova remnant, are also presented. The problem of finding model shells to fit the radio observations is considered and it is shown that the radio emission from 1439-62 is unlikely to originate in a shell with spherical symmetry.

scholarly journals A Galactic dust devil: far-infrared observations of the Tornado supernova remnant candidate

2020 ◽  
Vol 499 (4) ◽  
pp. 5665-5678
Author(s):  
H Chawner ◽  
A D P Howard ◽  
H L Gomez ◽  
M Matsuura ◽  
F Priestley ◽  
...  
Keyword(s):  
Radio Emission ◽  
Supernova Remnant ◽  
Far Infrared ◽  
Large Mass ◽  
Dust Devils ◽  
Infrared Observations ◽  
X Ray ◽  
Ss 433 ◽  
Multiple Regions ◽  
Tail Structure

ABSTRACT We present complicated dust structures within multiple regions of the candidate supernova remnant (SNR) the ‘Tornado’ (G357.7–0.1) using observations with Spitzer and Herschel. We use point process mapping, ppmap, to investigate the distribution of dust in the Tornado at a resolution of 8 arcsec, compared to the native telescope beams of 5–36 arcsec. We find complex dust structures at multiple temperatures within both the head and the tail of the Tornado, ranging from 15 to 60 K. Cool dust in the head forms a shell, with some overlap with the radio emission, which envelopes warm dust at the X-ray peak. Akin to the terrestrial sandy whirlwinds known as ‘dust devils’, we find a large mass of dust contained within the Tornado. We derive a total dust mass for the Tornado head of 16.7 $\rm M_{\odot }$, assuming a dust absorption coefficient of κ300 = 0.56 $\rm m^2\, kg^{-1}$, which can be explained by interstellar material swept up by a SNR expanding in a dense region. The X-ray, infrared, and radio emission from the Tornado head indicate that this is a SNR. The origin of the tail is more unclear, although we propose that there is an X-ray binary embedded in the SNR, the outflow from which drives into the SNR shell. This interaction forms the helical tail structure in a similar manner to that of the SNR W50 and microquasar SS 433.

scholarly journals Einstein Bragg Crystal Spectrometer Observations of Cas A – A Nonequilibrium Ionization Interpretation

1988 ◽  
Vol 101 ◽  
pp. 129-132 ◽  
Author(s):  
T.H. Markert ◽  
P.L. Blizzard ◽  
C.R. Canizares ◽  
J.P. Hughes
Keyword(s):  
Supernova Remnant ◽  
Crystal Spectrometer ◽  
Nonequilibrium Ionization ◽  
Cas A

AbstractWe use Einstein FPCS observations of lines of highly ionized neon, silicon and sulfur to constrain the parameters of the supernova remnant Cas A.

scholarly journals Chandra Study of the Central Object Associated with the Supernova Remnant MSH 11–62

2004 ◽  
Vol 218 ◽  
pp. 203-206
Author(s):  
Ilana Harrus ◽  
Joseph P. Bernstein ◽  
Patrick O. Slane ◽  
Bryan Gaensler ◽  
John P. Hughes ◽  
...  
Keyword(s):  
Neutron Star ◽  
Radio Emission ◽  
Supernova Remnant ◽  
Loss Rate ◽  
Thermal Emission ◽  
Compact Object ◽  
Small Region ◽  
Compact Source ◽  
Synchrotron Nebula ◽  
Compact Array

We present results from our analysis of Chandra data on the supernova remnant MSH 11–62 (also known as G291.0−0.1). Our previous ASCA analysis showed that MSH 11–62 is most likely a composite remnant whose strong non-thermal emission is powered by a compact object, most probably a pulsar. The present analysis confirms in a spectacular fashion the earlier detection of a compact source. The Chandra data reveal a small region with a hard non-thermal spectrum located at the tip of the central radio emission seen in data taken at the Australia Telescope Compact Array (ATCA). This source is likely the young rapidly rotating neutron star powering the synchrotron nebula in MSH 11–62. Compared to other young rotation-powered pulsars the Chandra specrum of MSH 11–62 implies an energy loss rate of Ė ∼ 5 × 1036 ergs s−1.

scholarly journals The Σ − D relation for planetary nebulae: Preliminary analysis

2007 ◽  
pp. 73-77 ◽  
Author(s):  
D. Urosevic ◽  
B. Vukotic ◽  
B. Arbutina ◽  
D. Ilic
Keyword(s):  
Preliminary Analysis ◽  
Surface Brightness ◽  
Supernova Remnant ◽  
Selection Effect ◽  
Planetary Nebulae

An analysis of the relation between radio surface brightness and diameter, so-called ? ? D relation, for planetary nebulae (PNe) is presented: i) the theoretical ? ? D relation for the evolution of bremsstrahlung surface brightness is derived; ii) contrary to the results obtained earlier for the Galactic supernova remnant (SNR) samples, our results show that the updated sample of Galactic PNe does not severely suffer from volume selection effect - Malmquist bias (same as for the extragalactic SNR samples) and; iii) we conclude that the empirical S ? D relation for PNe derived in this paper is not useful for valid determination of distances for all observed PNe with unknown distances. .

X-radiation fields in Cas A and Vir A

1968 ◽  
Vol 46 (10) ◽  
pp. S481-S483 ◽  
Author(s):  
Hugh M. Johnson
Keyword(s):  
Surface Brightness ◽  
X Ray ◽  
Radiation Fields ◽  
Optical Continuum ◽  
Cas A

Recent X-ray detection of the radio and optical sources Cas A (galactic) and Vir A (extra-galactic) provides new ways to relate the continua and line emissions in the spectra. The level of photoionization and the surface brightness of the optical continua are discussed. The apparent detection of part of the optical continuum of Cas A is also discussed.

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