The Heights of Solar Radio Sources at 1424 MHz and 696 MHz

1969 ◽  
Vol 1 (5) ◽  
pp. 192-194 ◽  
Author(s):  
D. G. Cole ◽  
R. F. Mullaly
Keyword(s):  
Solar Activity ◽  
High Resolution ◽  
Solar Disk ◽  
Previous Investigation ◽  
Solar Radio ◽  
Radio Sources ◽  
Grating Interferometer ◽  
Maximum Solar Activity

The heights of solar radio sources at 1424 MHz and 696 MHz have been measured during the years 1965 and 1966. Solar activity at this time was near minimum. The number of radio sources appearing on the solar disk rarely exceeded three at any time and it thus was possible to resolve the majority of these with a high resolution grating interferometer. Many of the previous height measurements at these frequencies have been made near times of maximum solar activity and the confusion of sources within the beam has limited their accuracy. The number of sources studied here is quite considerably higher than in any previous investigation at these frequencies, and the period of observation has been continuous.

scholarly journals Properties of sources of the slowly varying component of 2 cm solar radio emission

1968 ◽  
Vol 35 ◽  
pp. 575-580
Author(s):  
V. G. Nagnibeda
Keyword(s):  
High Resolution ◽  
Radio Emission ◽  
Radio Astronomy ◽  
Solar Radio ◽  
Emission Spectra ◽  
Active Regions ◽  
Solar Radio Emission ◽  
Radio Sources ◽  
Pulkovo Observatory ◽  
Local Sources

To study the nature of the local sources of solar radio emission connected with active regions, it is important to investigate the structure of such sources and their emission spectra. These problems are being investigated in detail by a group of workers of the Radio Astronomy Department of the Pulkovo Observatory led by G.B. Gelfreikh. The Pulkovo large radio telescope used for the observations allows them to investigate the solar radio sources at the whole cm-wavelength range with a high resolution reaching 40 sec of arc at the 2-cm wave. Observations are taken at 2·0, 3·2, 4·4, 6·6, and 9-cm waves. The author observes at the 2-cm wave.

scholarly journals High-resolution VLA low radio frequency observations of the Perseus cluster: radio lobes, mini-halo, and bent-jet radio galaxies

2020 ◽  
Vol 499 (4) ◽  
pp. 5791-5805
Author(s):  
M Gendron-Marsolais ◽  
J Hlavacek-Larrondo ◽  
R J van Weeren ◽  
L Rudnick ◽  
T E Clarke ◽  
...  
Keyword(s):  
High Resolution ◽  
Dynamic Range ◽  
Galaxy Cluster ◽  
High Dynamic Range ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Nearby Galaxy ◽  
Cluster Galaxy ◽  
Ngc 1275 ◽  
Perseus Cluster

ABSTRACT We present the first high-resolution 230–470 MHz map of the Perseus cluster obtained with the Karl G. Jansky Very Large Array. The high dynamic range and resolution achieved have allowed the identification of previously unknown structures in this nearby galaxy cluster. New hints of sub-structures appear in the inner radio lobes of the brightest cluster galaxy NGC 1275. The spurs of radio emission extending into the outer X-ray cavities, inflated by past nuclear outbursts, are seen for the first time at these frequencies, consistent with spectral aging. Beyond NGC 1275, we also analyse complex radio sources harboured in the cluster. Two new distinct, narrowly collimated jets are visible in IC 310, consistent with a highly projected narrow-angle tail radio galaxy infalling into the cluster. We show how this is in agreement with its blazar-like behaviour, implying that blazars and bent-jet radio galaxies are not mutually exclusive. We report the presence of filamentary structures across the entire tail of NGC 1265, including two new pairs of long filaments in the faintest bent extension of the tail. Such filaments have been seen in other cluster radio sources such as relics and radio lobes, indicating that there may be a fundamental connection between all these radio structures. We resolve the very narrow and straight tail of CR 15 without indication of double jets, so that the interpretation of such head–tail sources is yet unclear. Finally, we note that only the brightest western parts of the mini-halo remain, near NGC 1272 and its bent double jets.

scholarly journals The Radio Brightness Distribution on the Sun at 21 cm from Combined Eclipse and Pencil?Beam Observations

1961 ◽  
Vol 14 (3) ◽  
pp. 403 ◽  
Author(s):  
T Krishnan ◽  
NR Labrum
Keyword(s):  
High Resolution ◽  
High Sensitivity ◽  
Brightness Distribution ◽  
Pencil Beam ◽  
The Sun ◽  
Radio Brightness ◽  
Radio Brightness Distribution ◽  
Grating Interferometer

A study of the brightness distribution on the Sun at 21-cm wavelength on April 8, 1959, is described. High resolution observations were made of the partial eclipse on that day with a simple radiometer of high sensitivity. The brightness distribution of the uneclipsed Sun at the same wavelength was obtained using a cross-grating interferometer, which enabled the bright regions to be located accurately.

scholarly journals Evidence for the Transfer of Corpuscles to Distant Parts of the Sun Following a Solar Radio Burst

1961 ◽  
Vol 14 (4) ◽  
pp. 540 ◽  
Author(s):  
RF Mullaly
Keyword(s):  
Radio Burst ◽  
Solar Radio ◽  
Brightness Distribution ◽  
Solar Radio Burst ◽  
The Sun ◽  
Time Intervals ◽  
The Past ◽  
Grating Interferometer ◽  
Half Power ◽  
East West

The brightness distribution of 21-cm radiation over the Sun's surface has been studied for the past four years with the Christiansen crossed-grating interferometer (Christiansen et al. 1961) at Fleurs near Sydney. The observations described here were made using one arm of this cross as a simple grating interferometer, providing a transit instrument with a fan beam of about 2' of arc resolution to half-power points in the east-west direction and very low resolution north-south. The Sun was scanned repeatedly from east to west at time intervals of approximately 4 min.

scholarly journals VLBI Observations of Southern EGRET Identifications

1996 ◽  
Vol 175 ◽  
pp. 19-20
Author(s):  
J.E.J. Lovell ◽  
S.J. Tingay ◽  
P.G. Edwards ◽  
D.L. Jauncey ◽  
R.A. Preston
Keyword(s):  
High Resolution ◽  
Southern Hemisphere ◽  
Gamma Ray ◽  
Radio Sources ◽  
Vlbi Observations ◽  
First Results

We present high resolution VLBI images of three southern radio sources: PKS 0208–512, PKS 0521–365 and PKS 0537–441. These sources have been identified as > 100 MeV gamma-ray sources with the Energetic Gamma-Ray Telescope (EGRET) on board the Compton Gamma-Ray Observatory (Thompson et al. 1995). These are the first results in a continuing program of VLBI observations of southern EGRET identifications with the Southern Hemisphere VLBI Experiment (SHEVE) array of telescopes (Jauncey et al., 1994).

II. Spots and Intense Flux Tubes

1988 ◽  
Vol 20 (1) ◽  
pp. 58-63
Author(s):  
J.C. Henoux
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
High Resolution ◽  
Solar Magnetic Field ◽  
Solar Physics ◽  
Small Scale ◽  
The Sun ◽  
Flux Tubes ◽  
Flux Concentration ◽  
Scientific Meetings

The development of research on starspots, stellar activity, and the suspected relationship between coronal heating and magnetic field have reenforced the interest of the study of the solar magnetic field and the study of the associated thermodynamic structures. Several proceedings of scientific meetings appeared from 1984 to 1987 (Measurements of Solar Vector Magnetic Fields, 1985 (I); The Hydrodynamics of the Sun, 1984 (II); High Resolution in Solar Physics, 1985 (III); Theoritical Problems in High Resolution Solar Physics, 1985 (IV); Small Scale Magnetic Flux Concentration in the Solar Atmosphere, 1986 (V)). The finding that the solar irradiance in affected by solar activity has renewed interest in photometry of sunspots and faculae. Sunspots have been used for investigating solar differential and meridional motions. Some results are also found in Section III.

scholarly journals Low Frequency Radio Astronomy from Above the Ionosphere

2002 ◽  
Vol 199 ◽  
pp. 488-489
Author(s):  
D. L. Jones
Keyword(s):  
High Resolution ◽  
Radio Astronomy ◽  
Coronal Mass Ejections ◽  
Solar Radio ◽  
Low Frequency ◽  
Dramatic Improvement ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Low Frequencies ◽  
High Resolution Images

The GMRT represents a dramatic improvement in ground-based observing capabilities for low frequency radio astronomy. At sufficiently low frequencies, however, no ground-based facility will be able to produce high resolution images while looking through the ionosphere. A space-based array will be needed to explore the objects and processes which dominate the sky at the lowest radio frequencies. An imaging radio interferometer based on a large number of small, inexpensive satellites would be able to track solar radio bursts associated with coronal mass ejections out to the distance of Earth, determine the frequency and duration of early epochs of nonthermal activity in galaxies, and provide unique information about the interstellar medium.

High Resolution Solar Observations at Three Frequencies: 1424 MHz, 696 MHz and 408 MHz

1967 ◽  
Vol 1 (2) ◽  
pp. 45-46
Author(s):  
D. G. Cole ◽  
R. F. Mullaly ◽  
A. Watkinson
Keyword(s):  
High Resolution ◽  
Radio Emission ◽  
Solar Radio ◽  
Solar Radio Emission ◽  
The Sun ◽  
Physical Mechanisms ◽  
Solar Observations ◽  
Source Structure ◽  
East West

During the period 1966 July 12 to August 5 observations were made of the Sun at three radio observatories. The instruments used were the east-west arm of the Mills cross at Molonglo (408 MHz) and the Christiansen cross at Fleurs (696 MHz and 1424 MHz). The aim of these observations was to study the discrete sources of the slowly varying component of solar radio emission, while activity was comparatively quiet. The three frequencies enabled the variation of source structure with height of solar atmosphere to be studied. It has been pointed out by Swarup et al., and Christiansen et al. that the determination of the frequency dependence of these discrete sources is important for defining the physical mechanisms causing the radio emission.

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