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 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 Measurements Of The Flux Density Of Discrete Radio Sources At 6 Cm Wavelength

1966 ◽  
Vol 19 (4) ◽  
pp. 577 ◽  
Keyword(s):  
Flux Density ◽  
Radio Telescope ◽  
Power Law ◽  
Radio Sources ◽  
Frequency Range ◽  
Thermal Radio ◽  
Discrete Radio Sources ◽  
Selection Of ◽  
Lower Frequencies

The flux densities of 67 non-thermal radio sources have been measured at a frequency of 5000 Mc/s with the CSIRO 210 ft radio telescope at Parkes. The sources were chosen from the stronger objects in the 3C catalogue (Edge et al. 1959), the CTA and CTD catalogues (Harris and Roberts 1960; Kellermann and Read 1965), and the Parkes catalogue (Bolton, Gardner, and Mackey 1964; Price and Milne 1965; Day et al. 1966). In the selection of sources observed in this program, special emphasis was placed on objects whose spectra at lower frequencies showed significant departures from the usual power law with an index near -0�8. Most of the sources reported here have not been previously measured at wavelengths shorter than 10 cm and thus the present observations extend the frequency range of their spectra by nearly a factor of two.

scholarly journals Some new observations relating to galactic radio sources and background structure

1964 ◽  
Vol 20 ◽  
pp. 107-114 ◽  
Author(s):  
E. R. Hill
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Milky Way ◽  
Angular Resolution ◽  
Spectral Information ◽  
Radio Sources ◽  
Background Structure ◽  
The Galaxy ◽  
Galactic Radio

A survey of the distribution of radio emission at wavelengths of 75 and 20 cm along an extensive section of the Southern Milky Way has recently been carried out by M. Komesaroff and myself using the 210-foot radio telescope at Parkes. The area surveyed ranges from lII = 280 to 355° and extends on the average to 6 degrees either side of the plane. The beamwidths of the aerial at 75 and 20 cm are 50 and 14 min arc respectively. Observations at the shorter wavelength offer a picture of this section of the Galaxy at considerably higher angular resolution than hitherto available, while the 75-cm observations are expected to make a useful contribution to our spectral information.

Positions of Radio Sources Measured with the One-Mile Radio Telescope

Nature ◽  
1966 ◽  
Vol 210 (5031) ◽  
pp. 22-23 ◽  
Author(s):  
E. A. PARKER ◽  
B. ELSMORE ◽  
J. R. SHAKESHAFT
Keyword(s):  
Radio Telescope ◽  
Radio Sources ◽  
The One

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 ENVIRONMENT DENSITY OF A GIANT RADIO STRUCTURE FOR GALAXIES AND QUASARS WITH STEEP RADIO SPECTRA

2021 ◽  
Vol 26 (2) ◽  
pp. 165-172
Author(s):  
A. P. Miroshnichenko ◽  
Keyword(s):  
Low Frequency ◽  
Radio Spectrum ◽  
Power Relation ◽  
Cosmological Evolution ◽  
Inverse Power ◽  
Radio Sources ◽  
Frequency Spectra ◽  
Radio Structure ◽  
Mean Values ◽  
Index Value

Purpose: Estimate of the environment density of giant (with the linear size of about megaparsec) radio structures for galaxies and quasars with steep low-frequency spectra taken from the UTR-2 catalogue. Study of the cosmological evolution of environment density of giant radio sources. Determination of dependence of contribution of radio lobes into the emission of giant sources with respect to their environment density. Design/methodology/approach: We use the sample of sources from the UTR-2 catalogue of extragalactic sources to estimate the environment density for giant sources with steep low-frequency spectra. The selection criteria for the examined objects are the following: 1) the spectral index value is equal or larger than 1; 2) the fl ux density of emission at the frequency of 25 MHz is larger than 10 Jy; 3) the sample sources are optically identifi ed. The value of environment density of examined sources is obtained with the assumption of equality of source jet luminosity (at the synchrotron mechanism of radio emission) and its corresponding kinetic luminosity. The analysis of the estimates of environment densities is made for different classes of the sample objects (for galaxies and quasars with linear steep spectra and with break steep spectra). Findings: The estimates of environment density have been derived for giant radio structures formed by the jets of sources with steep spectrum from the UTR-2 catalogue. On the average, the environment density for the quasar structure (~ 10-28 g/sm3) is lesser than the one for the galaxies (~ 10-27 g/sm3 to ~ 10-26 g/sm3). The larger jet environment density is typical for the galaxies and quasars with the break steep spectra than for those with the linear steep spectra. The inverse power relation of the jet environment density and the source redshift (the cosmological evolution of the jet environment density) has been derived. The contribution of jet-related radio lobes into the emission of sources displays the inverse power relation for the environment density of the corresponding radio structures. Conclusions: The mean values of obtained estimates of environment density of giant jets of radio sources with steep low-frequency spectra indicate the lesser environment density of quasar jets than that for the galaxy jets. Giant radio sources with steep low-frequency spectrum (especially, with break steep spectrum) reveal considerable evolution of environment density of jets. The larger contribution of radio lobes (jets) into the emission of sources corresponds to the lesser environment density of sources taken from the UTR-2 catalogue. It can be due to propagation of jets (surrounded by radio lobes) from powerful radio sources to distances of about megaparsec, until the balance of source’s environment density and extragalactic environment density is reached. Key words: steep low-frequency radio spectrum; giant radio structure; jets; radio lobes; galaxies; quasars; environment density

scholarly journals The Problem of Identifying Decametric Sources

2002 ◽  
Vol 199 ◽  
pp. 215-216 ◽  
Author(s):  
O.V. Verkhodanov ◽  
H. Andernach ◽  
N.V. Verkhodanova
Keyword(s):  
Radio Spectrum ◽  
Radio Sources ◽  
Antenna Beam ◽  
Best Fit

We describe a method to cross-identify and construct continuum spectra for radio sources from decametric surveys with comparatively large positional errors. The 1822 sources from the UTR-2 catalogue (10—25 MHz, antenna beam of ∼40') were cross-identified with entries from other radio catalogues at higher frequencies. Using the CATS database we found accurate positions for 2314 counterparts to UTR sources, as well as a best-fit radio spectrum for most of these. About 350 (or 19%) of the UTR sources appear to be blends of two or more sources.

High-resolution Measurements of the Galactic Radio Spectrum

1969 ◽  
Vol 1 (5) ◽  
pp. 210-211 ◽  
Author(s):  
T. L. Landecker ◽  
R. Wielebinski
Keyword(s):  
High Resolution ◽  
Radio Emission ◽  
High Latitude ◽  
Galactic Plane ◽  
Background Radiation ◽  
Radio Spectrum ◽  
Synchrotron Emission ◽  
Detailed Structure ◽  
Detailed Understanding ◽  
Galactic Radio

High-resolution surveys of the galactic radio emission show detailed structure both near the galactic plane and at high galactic latitudes. Some of this structure is describable as ‘spurs’ while the rest comprises isolated features. We describe here measurements of the spectral index of the background radiation with a resolution of 3°.5. These measurements are aimed at a detailed understanding of the high-latitude synchrotron emission.

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