Observations of (S III) emission from Galactic radio sources - The detection of distant planetary nebulae and a search for supernova remnant emission

1993 ◽  
Vol 105 ◽  
pp. 2199 ◽  
Author(s):  
V. Kistiakowsky ◽  
D. J. Helfand
Keyword(s):  
Supernova Remnant ◽  
Planetary Nebulae ◽  
Radio Sources ◽  
Galactic Radio

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 Catalogue of Galactic Radio Sources

1968 ◽  
Vol 21 (3) ◽  
pp. 369 ◽  
Author(s):  
MJL Kesteven
Keyword(s):  
Flux Density ◽  
Spectral Index ◽  
Galactic Plane ◽  
Radio Sources ◽  
Galactic Radio

The results of a survey of radio sources in the galactic plane in the longitude range 1800 to 400 with the 1 mile Molonglo Cross telescope at 408 MHz are presented. The methods of observation and reduction are described briefly. The catalogue lists the position, flux density, size, and spectral index for 80 sources

scholarly journals G18.95-1.1, A Composite Supernova Remnant Interacting with the Ambient Interstellar Medium

1988 ◽  
Vol 101 ◽  
pp. 253-256
Author(s):  
E. Fürst ◽  
W. Reich ◽  
E. Hummel ◽  
Y. Sofue
Keyword(s):  
Spectral Line ◽  
Interstellar Medium ◽  
Radio Source ◽  
Supernova Remnant ◽  
Radio Continuum ◽  
New Radio ◽  
Galactic Radio

AbstractNew radio continuum and spectral line observations of the Galactic radio source G18.95-1.1 are reported. The distance to G18.95-1.1 is 2 kpc as derived from HI-21 cm spectral line observations. These data also indicate an interaction with the interstellar medium. The radio continuum observations classify G18.95-1.1 as a composite supernova remnant.

scholarly journals Variable Radio Sources

1982 ◽  
Vol 97 ◽  
pp. 317-324 ◽  
Author(s):  
R. Fanti ◽  
L. Padrielli ◽  
M. Salvati
Keyword(s):  
Energy Supply ◽  
Theoretical Models ◽  
Accelerated Expansion ◽  
Radio Sources ◽  
Relativistic Electrons ◽  
Plasma Cloud ◽  
Basic Process ◽  
Continuous Energy ◽  
Galactic Radio ◽  
Variable Radio

Flux variations are a common feature of flat spectrum compact extra-galactic radio sources. Detailed analysis and quantitative comparisons with theoretical models (e.g. van der Laan, 1966) are difficult due to the complex characteristics of the flux variations, which generally appear to consist of different outbursts blended together in time. Nevertheless, the general consensus is that the basic process has been correctly identified and consists in an expansion of a synchrotron radiating plasma cloud of relativistic electrons and magnetic field partially opaque to its own radiation. The main differences between data and predictions of the theory are that the variations propagate too fast and with too large amplitude toward lower frequencies. This behaviour however may be indicative of continuous energy supply and consequent accelerated expansion.

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. .

scholarly journals The Rotation Measure of Background Radio Sources Seen Through the Supernova Remnant OA184 (G166.2+2.5)

1988 ◽  
Vol 101 ◽  
pp. 355-358
Author(s):  
K.-T. Kim ◽  
P.P. Kronberg ◽  
T.L. Landecker
Keyword(s):  
Magnetic Field ◽  
Supernova Remnant ◽  
Active Plasma ◽  
Radio Sources ◽  
Galactic Magnetic Field ◽  
Rotation Measure ◽  
Polarity Change ◽  
Larger Sample

AbstractRadio sources in the field of the extended SNR OA184 (G166.2+2.5) have been studied to determine the excess rotation measure (RM) arising from the SNR. Of a total of 32 radio sources observed with the VLA in the C configuration, eight are found to be polarized above 7σ The sources seen through the SNR show significantly high RM in comparison to background sources. The excess RM due to the Faraday active plasma in the SNR is estimated to be 150±20 rad m−2, which corresponds to . The sign of RMs of the sources within an area of about 2°×2° centred on the SNR shows a systematic longitudinal polarity change on either side of l ≈ 166°.2. Although a larger sample is needed to justify this, we tentatively interpret this “flip” as due to the reversal of an irregular component of the galactic magnetic field on a scale of order 100 pc.

Observations of Shell-Type Galactic Radio Sources

1967 ◽  
Vol 1 (1) ◽  
pp. 21-21 ◽  
Author(s):  
E. R. Hill
Keyword(s):  
Radio Telescope ◽  
Shell Structure ◽  
Radio Spectrum ◽  
Radio Sources ◽  
Thermal Radio ◽  
Shell Type ◽  
Galactic Radio

Survey type observations have been made with the Parkes radio-telescope of 4 galactic radio sources having either a non-thermal radio spectrum, or exhibiting shell structure in their emitting regions. Observations were made at a wavelength of 11 cm using the Parkes radiotelescope where the beamwidth is about 7.5 min.arc.

scholarly journals 178 MHz Observations of Galactic Radio Sources

1969 ◽  
Vol 143 (4) ◽  
pp. 407-435 ◽  
Author(s):  
D. J. Holden ◽  
J. L. Caswell
Keyword(s):  
Radio Sources ◽  
Galactic Radio
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