scholarly journals Radio Emission from Clusters of Galaxies

1967 ◽  
Vol 20 (6) ◽  
pp. 715 ◽  
Author(s):  
HM Tovmassian ◽  
IG Moiseev
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Radio Astronomy ◽  
Mathematical Expectation ◽  
Astronomical Observatory ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Astronomy Observatory ◽  
Group 5 ◽  
East West

From Abell's (1958) list of clusters of galaxies, 137 clusters of distance group 5 were observed at 1410 MHz with the 210 ft radio telescope of the Australian National Radio Astronomy Observatory at Parkes. The detected radio sources were further confirmed hy observations at 2650 MHz with the same telescope and at 408 MHz with the east-west arm of the Mills Cross at the Molonglo Radio Astronomical Observatory. A total of 25 radio sources was detected within 5' arc of the centres of corresponding clusters of galaxies, while the mathematical expectation of the number of random coincidences with clusters is about two or three

scholarly journals Observations of Some Radio Sources Previously Identified with Clusters of Galaxies

1967 ◽  
Vol 20 (6) ◽  
pp. 725
Author(s):  
HM Tovmassian ◽  
IG Moiseev
Keyword(s):  
Radio Telescope ◽  
Radio Astronomy ◽  
Astronomical Observatory ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Astronomy Observatory ◽  
Radio Astronomy Observatory ◽  
The University ◽  
East West

The positions of 33 radio sources previously identified with distant clusters of galaxies were remeasured more accurately to check the identifications. Observations were made at 1410 and 2650 MHz with the 210 ft radio telescope of the Australian National Radio Astronomy Observatory at Parkes, and at 408 MHz with the east-west arm of the Mills Cross at the Molonglo Radio Astronomical Observatory of the University of Sydney. It was found that 21 sources are situated within 5 min of arc of the centres of the corresponding clusters.

scholarly journals Radio Emission Of The Nuclei Of Barred Spiral Galaxies

1966 ◽  
Vol 19 (6) ◽  
pp. 883 ◽  
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Radio Astronomy ◽  
Spiral Galaxies ◽  
Astronomy Observatory ◽  
Radio Observations ◽  
Barred Galaxies ◽  
Radio Astronomy Observatory ◽  
Barred Spiral Galaxies

The results of radio observations of 98 barred galaxies at 11, 21, and 75 cm are presented. The observations were carried out with the 210 ft radio telescope of the Australian National Radio Astronomy Observatory and with the Mills Cross of the Sydney Uni

scholarly journals 12. The measurement of the distance of the radio sources

1957 ◽  
Vol 4 ◽  
pp. 71-79 ◽  
Author(s):  
R. D. Davies ◽  
D. R. W. Williams
Keyword(s):  
Radio Emission ◽  
Surface Area ◽  
Radio Astronomy ◽  
Angular Size ◽  
Radio Sources ◽  
Absolute Luminosity

In radio astronomy it is becoming increasingly important to know the distance of the radio sources. An identification with astronomical objects observed optically is then more readily obtained and this in turn may allow further investigation of the mechanism of radio emission. A measurement of the distance of sources will also resolve the problem of their distribution in space, showing which are galactic and which are extra-galactic. Furthermore the surface area and absolute luminosity can be estimated from a knowledge of the distance and angular size of a source.

scholarly journals Clusters with extended radio emission at high frequencies

1978 ◽  
Vol 79 ◽  
pp. 157-159
Author(s):  
R. Wielebinski
Keyword(s):  
Radio Emission ◽  
Direct Measurement ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Coma Cluster ◽  
Extended Source ◽  
High Frequencies ◽  
Extended Radio ◽  
Extended Component ◽  
Perseus Cluster

The existence of ‘haloes’ in clusters of galaxies was deduced by Ryle and Windram (1968) for the Perseus cluster and by Willson (1970) for the Coma cluster at 408 MHz by comparing total flux measured by a single dish with the sum of fluxes of radio sources found in the field. A direct measurement of the extended source Coma C was made by Jaffe et al. (1976) at 610 MHz. the failure to detect the halo of Coma at higher frequencies is attributed by all authors to a steep spectrum of this extended component.

scholarly journals The Intergalactic Medium

1982 ◽  
Vol 97 ◽  
pp. 453-459
Author(s):  
A. C. Fabian ◽  
A. K. Kembhavi
Keyword(s):  
Radio Emission ◽  
Intergalactic Medium ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Intergalactic Gas ◽  
X Ray ◽  
Extended Radio ◽  
X Ray Background ◽  
Ngc 1275 ◽  
Intracluster Gas

The density of intergalactic gas may be an important parameter in the formation of extended radio sources. It may range from ∼ 0.1 particle cm−3 in the centres of some rich clusters of galaxies down to 10−8cm−3 or less in intercluster space. The possible influence of the intracluster gas surrounding NGC 1275 on its radio emission is discussed, and the possibility that a significant fraction of the X-ray background is due to a hot intergalactic medium is explored in some detail.

scholarly journals Radio Sources in Clusters of Galaxies

1968 ◽  
Vol 21 (4) ◽  
pp. 511 ◽  
Author(s):  
BY Mills ◽  
RR Shobbrook ◽  
D Stewart-Richardson
Keyword(s):  
Radio Emission ◽  
Radio Source ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Cluster Galaxy ◽  
Stellar Objects ◽  
Cluster Emission ◽  
Cluster Galaxies ◽  
Individual Cluster

Fifty-eight clusters from Abell's catalogue have been examined for radio emission using the Arecibo l000 ft reflector and the Molonglo 1 mile Cross. The positions, sizes, and flux densities at 408 MHz of 30 radio sources close to these clusters have been measured. Nineteen of these offer reasonable identifications with galaxies or blue stellar objects. Thirteen appear to be identifiable with individual cluster galaxies. No evidence for integrated cluster emission has been obtained. It has been concluded that either the centroid of radio sources may sometimes be well displaced from the parent galaxies or, in a significant number of cases, the only detectable radio source in a cluster is associated with a faint cluster galaxy, not a giant.

scholarly journals The Parkes Catalogue Of Radio Sources Declination Zone 0° To ?20°

1966 ◽  
Vol 19 (6) ◽  
pp. 837 ◽  
Keyword(s):  
Radio Astronomy ◽  
Radio Sources ◽  
Astronomy Observatory ◽  
Radio Astronomy Observatory

This paper gives details of 628 radio sources between declinations 0� and - 20� compiled from observations made at 408 Mc/s with the 210 ft reflector at the Australian National Radio Astronomy Observatory, Parkes, N.S.W.

scholarly journals Pulsar Observations at the Ghana Radio Astronomy Observatory

2017 ◽  
Vol 13 (S337) ◽  
pp. 410-411
Author(s):  
T. W. Scragg ◽  
B. W. Stappers ◽  
R. P. Breton ◽  
J. N. Smith ◽  
D. Adomako ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Radio Astronomy ◽  
Astronomy Observatory ◽  
Earth Station ◽  
Radio Astronomy Observatory ◽  
Pulsar Timing ◽  
New Radio ◽  
Timing System

AbstractIn August 2017 a new radio telescope, the Ghana Radio Astronomy Observatory (GRAO), was officially inaugurated at Kuntunse, Ghana. The GRAO is a former satellite Earth station and now the first operational station in the African VLBI Network (AVN). The Jodrell Bank Centre for Astrophysics (JBCA), supported by the UK’s STFC/Newton Fund, has developed a new pulsar timing system (Hebe) for the GRAO. We present some aspects of the design of Hebe and an outline of the first pulsar detection at GRAO.

scholarly journals Westerbork Surveys of Radio Sources at 610 and 1415 MHz

1977 ◽  
Vol 74 ◽  
pp. 39-45 ◽  
Author(s):  
A. G. Willis ◽  
C. E. Oosterbaan ◽  
R. S. Le Poole ◽  
H. R. de Ruiter ◽  
R. G. Strom ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Radio Sources ◽  
Clusters Of Galaxies

The Westerbork Synthesis Radio Telescope (WSRT) has now been used to make source surveys at frequencies of 610 and 1415 MHz. This paper summarizes the results concerning source counts and anisotropies in the distribution of sources from those surveys not concerned with clusters of galaxies.

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