scholarly journals Radio Emission of 158 Galaxies

1968 ◽  
Vol 21 (2) ◽  
pp. 193 ◽  
Author(s):  
HM Tovmassian
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Spiral Galaxies ◽  
Radio Observations ◽  
Central Regions ◽  
The University ◽  
East West

Radio observations of Hi8 mainly spiral galaxies have been made at 21 em and additional observations have been made for some at 11 and 75 em. The observations at 11 and 21 cm were made with the CSIR<z 210 ft radio telescope at Parkes and those at 75 cm with the east-west arm of the Mills Cross at the Molonglo Observatory of the University of Sydney. Radio emission was detected from central regions of 20 of the galaxies.

scholarly journals On The Radio Emission From Some Peculiar Galaxies

1966 ◽  
Vol 19 (4) ◽  
pp. 565 ◽  
Keyword(s):  
Radio Emission ◽  
Optical Spectra ◽  
Emission Lines ◽  
Relativistic Electrons ◽  
Radio Observations ◽  
Central Regions ◽  
The University ◽  
East West ◽  
Peculiar Galaxies

Radio observations have been made of 18 galaxies whose spectra and colours in their central regions are abnormal for their morphological types (Markarian 1963). Observations at 1410 and 2650 Mcls were made with the CSIRO 210 ft steerab1e telescope at Parkes, and at 408 Mcls with the east-west arm of the Mills Cross at the Molonglo Observatory of the University of Sydney. Radio emission was detected from the central regions of 13 of these galaxies. For these 13 the radio index (mr-mpg) is about 1�2 and differs by IiLbout two magnitudes from that of normal spirals. Absolute radio magnitudes of the galaxies are about -21�0. In most cases the presence of radio emission is accompanied by emission lines in the optical spectra. It is concluded that the enhanced radio emission of the galaxies investigated is due to the production of relativistic electrons in their active nuclei.

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 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 Radio Emission from Fourteen Planetary Nebulae at 408 MHz

1968 ◽  
Vol 34 ◽  
pp. 104-105
Author(s):  
Cesare Barbieri ◽  
Antonino Ficarra
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Planetary Nebulae ◽  
East West

The East-West arm of the ‘Northern Cross’ radio telescope of the Bologna University has been used to observe 14 planetary nebulae at the frequency of 408 MHz.

scholarly journals On the Correlation of the FIR and Radio Radiation of Spiral Galaxies

1994 ◽  
Vol 159 ◽  
pp. 337-337
Author(s):  
H. M. Tovmassian
Keyword(s):  
Radio Emission ◽  
Spiral Galaxies ◽  
Radio Radiation ◽  
Radio Observations ◽  
Definite Correlation

The comparison of the Byurakan classification of central parts of galaxies with the results of their radio observations showed that there is a definite correlation: the radio emission is more often observed in those galaxies which were suggested to have active nuclei.

scholarly journals The Radio Properties of a Complete Sample of Bright Galaxies

1982 ◽  
Vol 35 (3) ◽  
pp. 321 ◽  
Author(s):  
JI Harnett
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Spiral Galaxies ◽  
Radio Continuum ◽  
Spectral Indices ◽  
Radio Luminosity ◽  
Complete Sample ◽  
Luminosity Functions ◽  
The Mean

Results are given for the radio continuum properties of an optically complete sample of 294 bright galaxies, 147 of which have been detected. Data were obtained with the 408 MHz Molonglo Radio Telescope. The radio luminosity functions for all galaxies and for spiral galaxies alone are derived and the radio emission for different galaxy types is investigated. Spectral indices of 73 galaxies which had been detected at other frequencies were derived; the mean index of a reliable subsample is <ex) = -0,71.

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 A Low frequency Southern Sky Survey Using the Mauritius Radio Telescope

2002 ◽  
Vol 199 ◽  
pp. 25-31
Author(s):  
N. Udaya Shankar
Keyword(s):  
Radio Telescope ◽  
Low Frequency ◽  
Fourier Synthesis ◽  
North East ◽  
The North ◽  
Sky Survey ◽  
Correlation Receiver ◽  
Complex Correlation ◽  
Right Ascension ◽  
East West

The Mauritius Radio Telescope (MRT) is a Fourier synthesis instrument which has been built to fill the gap in the availability of deep sky surveys at low radio frequencies in the southern hemisphere. It is situated in the north-east of Mauritius at a southern latitude of 20°.14 and an eastern longitude of 57°.73. The aim of the survey with the MRT is to contribute to the database of southern sky sources in the declination range −70° ≤ δ ≤ −10°, covering the entire 24 hours of right ascension, with a resolution of 4' × 4'.6sec(δ + 20.14°) and a point source sensitivity of 200 mJy (3σ level) at 151.5 MHz.MRT is a T-shaped non-coplanar array consisting of a 2048 m long East-West arm and a 880 m long South arm. In the East-West arm 1024 fixed helices are arranged in 32 groups and in the South arm 16 trolleys, with four helices on each, which move on a rail are used. A 512 channel, 2-bit 3-level complex correlation receiver is used to measure the visibility function. At least 60 days of observing are required for obtaining the visibilities up to the 880 m spacing. The calibrated visibilities are transformed taking care of the non-coplanarity of the array to produce an image of the area of the sky under observation.This paper will describe the telescope, the observations carried out so far, a few interesting aspects of imaging with this non-coplanar array and present results of a low resolution survey (13' × 18') covering roughly 12 hours of right ascension, and also present an image with a resolution of 4' × 4'.6sec(δ + 20.14°) made using the telescope.

Time Variation of the Radio Emission from Sco X-1

1969 ◽  
Vol 1 (5) ◽  
pp. 237-240 ◽  
Author(s):  
J. G. Ables
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Time Variation ◽  
Radio Observatory ◽  
Half Power

The radio object associated with Sco X—1 noted by Andrew and Purton has been observed at a wavelength of 6 cm with the 210 ft radio telescope at the Australian National Radio Observatory, Parkes. At this wavelength the half-power antenna beamwidth is 4′ arc.

Conditions needed for generation of type II radio emission in the interplanetary space

2021 ◽  
Author(s):  
Immanuel Christopher Jebaraj ◽  
Athanasios Kouloumvakos ◽  
Jasmina Magdalenic ◽  
Alexis Rouillard ◽  
Vratislav Krupar ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Radio Emission ◽  
Interplanetary Space ◽  
Region Of Interest ◽  
Type Ii ◽  
Radio Observations ◽  
Wave Parameters ◽  
First Results ◽  
Radio Signature

&lt;p&gt;Eruptive events such as Coronal mass ejections (CMEs) and flares cangenerate shock waves. Tracking shock waves and predicting their arrival at Earth is a subject of numerous space weather studies. Ground-based radio observations allow us to locate shock waves in the low corona while space-based radio observations provide us opportunity to track shock waves in the inner heliosphere. We present a case study of CME/flare event, associated shock wave and its radio signature, i.e. type II radio burst.&lt;/p&gt;&lt;p&gt;In order to analyze the shock wave parameters, we employed a robust paradigm. We reconstructed the shock wave in 3D using multi-viewpoint observations and modelled the evolution of its parameters using a 3D MHD background coronal model produced by the MAS (Magnetohydrodynamics Around a Sphere).&lt;/p&gt;&lt;p&gt;To map regions on the shock wave surface, possibly associated with the electron acceleration, we combined 3D shock modelling results with the 3D source positions of the type II burst obtained using the radio triangulation technique. We localize the region of interest on the shock surface and examine the shock wave parameters to understand the relationship between the shock wave and the radio event. We analyzed the evolution of the upstream plasma characteristics and shock wave parameters during the full duration of the type II radio emission. First results indicate that shock wave geometry and its relationship with shock strength play an important role in the acceleration of electrons responsible for the generation of type II radio bursts.&lt;/p&gt;

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