scholarly journals Radio Emission from 16 Possible Supernova Remnants

1969 ◽  
Vol 22 (2) ◽  
pp. 211 ◽  
Author(s):  
DK Milne ◽  
ER Hill
Keyword(s):  
Radio Emission ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Radio Sources

Sixteen radio sources, thought to be supernova remnants, have been observed at several frequencies between 408 and 2700 MHz. These data, together with previously published observations, have been used to derive spectra for these sources. The validity of the supernova remnant classification of certain of these sources is questioned.

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 Classification of Supernova Remnants and HII Regions from their Recombination Line Emission

1972 ◽  
Vol 25 (5) ◽  
pp. 539 ◽  
Author(s):  
JR Dickel ◽  
DK Milne
Keyword(s):  
Electron Temperature ◽  
Supernova Remnants ◽  
Line Emission ◽  
Hii Regions ◽  
Radio Sources ◽  
Recombination Line ◽  
Line Frequency ◽  
Upper Limits ◽  
Galactic Radio

H109a, recombination line observations are used in an attempt to classify 46 galactic radio sources as either supernova remnants or HII regions. Long integrations at the H109a line frequency on two well-known supernova remnants (IC 443 and 3C 391) provide improved upper limits on the line emission from these objects. From these results the electron temperature in IC 443 is estimated to be in excess of 1�6 � 104 K.

scholarly journals 8·8 GHz Radio Observations of 12 Suggested Supernova Remnants

1973 ◽  
Vol 26 (3) ◽  
pp. 379 ◽  
Author(s):  
JR Dickel ◽  
DK Milne ◽  
AR Kerr ◽  
JG Ables
Keyword(s):  
Flux Density ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Galactic Plane ◽  
Small Diameter ◽  
Radio Sources ◽  
Radio Observations ◽  
Frequency Measurements ◽  
Thermal Spectrum

Brightness distributions and flux densities at 8�8 GHz are presented for 12 small-diameter radio sources near the galactic plane. Each of these sources has been classified at one time or another as a supernova remnant. For one source, G295� 2 - 0�6, the flux density at 8�8 GHz confirms the thermal spectrum suggested by lower frequency measurements and indicates that it is not a supernova remnant. Another source, G309� 6+ 1�7, is thought to be extragalactic.

scholarly journals Radio Emission from the Supernova Remnant Vela-X

1968 ◽  
Vol 21 (2) ◽  
pp. 201 ◽  
Author(s):  
DK Milne
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Radio Emission ◽  
Spectral Index ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Magnetic Field Direction ◽  
Radio Observations ◽  
Optical Identification ◽  
Polarization Measurements

Radio observations are presented of the fairly large galactic complex Vela-X, Y, and Z. These sources are believed to be the remnant of a supernova having an optical identification with the filamentary nebula Stromlo 16. The brightness distributions, obtained at four frequencies, indicate an open annular structure reminiscent of other supernova remnants. The variation of spectral index over the region is investigated and shows that the radiation is substantially nontherm81, the integrated fluxes yielding a spectral index of -0,3. A high resolution distribution of magnetic field direction is deduced from polarization measurements made at three frequencies; a circumferential magnetic field is a possible interpretation of the field orientations.

scholarly journals Search for Nonthermal X-Rays from Supernova Remnant Shells

1998 ◽  
Vol 188 ◽  
pp. 117-120
Author(s):  
R. Petre ◽  
J. Keohane ◽  
U. Hwang ◽  
G. Allen ◽  
E. Gotthelf
Keyword(s):  
Radio Emission ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Cosmic Ray ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Nonthermal Radio ◽  
Cosmic Ray Acceleration ◽  
Nonthermal Radio Emission

The suggestion that the shocks of supernova remnants (SNR's) are cosmic ray acceleration sites dates back more than 40 years. While observations of nonthermal radio emission from SNR shells indicate the ubiquity of GeV cosmic ray production, there is still theoretical debate about whether SNR shocks accelerate particles up to the well-known “knee” in the primary cosmic ray spectrum at ~3,000 TeV. Recent X-ray observations of SN1006 and other SNR's may have provided the missing observational link between SNR shocks and high energy cosmic ray acceleration. We discuss these observations and their interpretation, and summarize our ongoing efforts to find evidence from X-ray observations of cosmic ray acceleration in the shells of other SNR's.

scholarly journals Investigations of Recently Discovered Supernova Remnants’ Spectral Plot: AT2019fya, SN2019fjp, SN2019fcc, SN2019fbv, SN2019ffi, and SN2019fce

2020 ◽  
Vol 84 ◽  
pp. 1-9
Author(s):  
Bjorn Jasper R. Raquel ◽  
Agnes C. Bantaculo ◽  
Shane Carlo B. Llemit ◽  
Eldrin P. Custodio
Keyword(s):  
Supernova Remnants ◽  
Supernova Remnant ◽  
Crab Nebula ◽  
Type Ii ◽  
Plot Analysis ◽  
The Individual ◽  
The Crab Nebula

This paper presents the spectroscopic graphs of recently discovered Supernova Remnants (AT2019fya, SN2019fjp, SN2019fcc, SN2019fce, SN2019fbv & SN2019ffi) for the determination of elements present. The researchers use the spectral plot analysis to analyze the presence of certain elements of the individual supernova remnants (SNR) for the assimilation, differentiation and classification of these SNR. Redshift and velocities of these SNR were also found using the observed wavelength and the rest wavelength ratio. Comparison suggests that AT2019fya is a Type II supernova remnant and some of the SNRs in this study exhibits an existence of krypton (Kr) on their composition which is recently discovered by M. Barlow (2013) to be present at the Crab Nebula. This might suggest that AT2019fya, SN2019fbv, SN2019fce, and SN2019ffi have a pulsar at their center.

scholarly journals Radio-Emission from Supernovae Remnants in Distant Galaxies

1972 ◽  
Vol 44 ◽  
pp. 82-86
Author(s):  
P. Notni ◽  
H. Oleak ◽  
G.-M. Richter
Keyword(s):  
Radio Emission ◽  
Supernova Remnants ◽  
Spiral Galaxies ◽  
Radio Sources ◽  
Distant Galaxies ◽  
Normal Spiral

It is suggested that some 5C2 radio sources previously identified with normal spiral galaxies, are associated with supernova remnants in these galaxies. This hypothesis is tested by the relative radio and optical positions and by luminosity estimates. It could be further tested by possible coincidences of Ohio radio sources with known supernovae, and also by predicted decreases in radio emission.

scholarly journals The Evolution of Supernova Remnants as Radio Sources

1983 ◽  
Vol 101 ◽  
pp. 187-192
Author(s):  
R. Cowsik ◽  
S. Sarkar
Keyword(s):  
Radio Emission ◽  
Interstellar Medium ◽  
Supernova Remnants ◽  
Structural Evolution ◽  
Radio Sources ◽  
Relativistic Electrons ◽  
Shell Type

The acceleration of relativistic electrons by hydromagnetic turbulence in shell-type supernova remnants (SNRs) is examined within the framework of previous studies of their structural evolution through interaction with the interstellar medium. The predicted evolution of the synchrotron radio emission by the electrons is in agreement with a wide variety of observations.

scholarly journals Radio Emission from Novae and Supernovae

1956 ◽  
Vol 9 (1) ◽  
pp. 84 ◽  
Author(s):  
BY Mills ◽  
AG Little ◽  
KV Sheridan
Keyword(s):  
Radio Emission ◽  
Supernova Remnants ◽  
Milky Way ◽  
Radio Sources ◽  
Constant Ratio ◽  
Radio Observations ◽  
Maximum Emission ◽  
Galactic Radio Emission ◽  
Galactic Radio

Attempts have been made to observe the radio emission at 3?5 m from two supernovae and ten novae. Kepler's star was the only reasonably certain identification. A comparison with radio observations of other supernova remnants suggests a constant ratio between the present radio emission and the maximum emission of light. It is concluded that for common novae, which are not detectable as radio sources, this ratio must be smaller than for supernovae. The galactic radio emission near the plane of the Milky Way could be largely the integrated emission of supernova remnants but common novae could not contribute appreciably.

Demise of a Galactic Supernova Remnant Candidate, G274.68–2.84

1991 ◽  
Vol 9 (1) ◽  
pp. 103-104 ◽  
Author(s):  
J. L. Caswell ◽  
R. T. Stewart
Keyword(s):  
Supernova Remnants ◽  
Supernova Remnant ◽  
Radio Sources ◽  
X Ray ◽  
New Radio ◽  
Radio Map

AbstractYoung supernova remnants are poorly understood and few are known. Further examples may be present, but unrecognised, within existing catalogues of radio sources. G274.68–2.84 was recently suggested as one such candidate but our new radio map from the Australia Telescope indicates that it is not a supernova remnant. Rather, it appears to be extragalactic with a strong, variable, flat-spectrum nucleus, and a bright X-ray counterpart.

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