scholarly journals Galactic Radiation at Radio Frequencies. VII. Discrete Sources with Large Angular Widths

1954 ◽  
Vol 7 (1) ◽  
pp. 96 ◽  
Author(s):  
JG Bolton ◽  
KC Westfold ◽  
GJ Stanley ◽  
OB Slee
Keyword(s):  
Angular Width ◽  
Radio Frequencies ◽  
Galactic Radiation

Observations with three forms of equipment have revealed the existence of a number of sources of angular width more than 1�.

scholarly journals Galactic Radiation at Radio Frequencies. V. The Sea Interferometer

1953 ◽  
Vol 6 (4) ◽  
pp. 420 ◽  
Author(s):  
JG Bolton ◽  
OB Slee
Keyword(s):  
Radio Frequencies ◽  
Galactic Radiation

The factors involved in the study of discrete sources of galactic noise by the sea interferometer are discussed. Three new forms of sea interferometer which increase the effectiveness of this technique are described.

scholarly journals Galactic Radiation at Radio Frequencies. VI. Low Altitude Scintillations of the Discrete Sources

1953 ◽  
Vol 6 (4) ◽  
pp. 434 ◽  
Author(s):  
JG Bolton ◽  
OB Slee ◽  
GJ Stanley
Keyword(s):  
Diurnal Variations ◽  
Scintillation Index ◽  
Seasonal Component ◽  
Seasonal And Diurnal Variations ◽  
Low Altitude ◽  
Radio Frequencies ◽  
Galactic Radiation

A study has been made of the scintillations of four discrete sources at altitudes of from 0 to 10�. The observations cover the years 1947?1951 and were made at various frequencies in the range 40?300 Mc/s. It was found that the scintillation index, a measure of the amplitude of the scintillations, (1) increases with increasing wavelength, (2) decreases rapidly with increasing altitude, (3) shows seasonal and diurnal variations, the seasonal component having minima near the equinoxes and the diurnal component near dawn and sunset. The scintillation rate or the number of scintillations per minute (1) is different for sources of different declination, (2) is independent of wavelength. In the case of the Cygnus source, the data for which are the most extensive, the rate increases and the decline in the scintillation index with altitude is less rapid during the winter months.

Galactic Radiation at Radio Frequencies. I. 100 MC/S. Survey

1950 ◽  
Vol 3 (1) ◽  
pp. 19 ◽  
Author(s):  
JG Bolton ◽  
KC Westfold
Keyword(s):  
Body Temperature ◽  
Black Body ◽  
Polar Diagram ◽  
Equal Area ◽  
Radio Frequencies ◽  
Celestial Sphere ◽  
Galactic Radiation

This paper contains an account of a survey of galactic radiation at a frequency of 100 Mc/s. An aerial array with a 17� beamwidth, on an equatorial mounting, was used to plot the distribution of intensity over the section of the celestial sphere between Declination +30� and -90�. The method of eliminating the effect of the aerial polar diagram from the observations is described and the final distribution, expressed in terms of equivalent black-body temperature, is presented in galactic coordinates on a series of equal-area charts. I.

Galactic Radiation at Radio Frequencies. III. Galactic Structure

1950 ◽  
Vol 3 (2) ◽  
pp. 251
Author(s):  
JG Bolton ◽  
KC Westfold
Keyword(s):  
Radio Frequency ◽  
Spiral Galaxy ◽  
Galactic Structure ◽  
The Sun ◽  
Frequency Data ◽  
Spiral Form ◽  
The Galaxy ◽  
Radio Frequencies ◽  
Optical Evidence ◽  
Galactic Radiation

From radio-frequency observations it is deduced that the sun is situated in or near an arm of a spiral galaxy. The first part of this paper consists of an analysis of the radio-frequency data followed by the presentation of optical evidence in favour of a spiral form. The sense of rotation of the Galaxy -that of the spiral unwinding- is in accordance with the theories of Lindblad and Milne.

scholarly journals Galactic Radiation at Radio Frequencies. VIII. Discrete Sources at 100 Mc/s Between Declinations +50° and ?50°

1954 ◽  
Vol 7 (1) ◽  
pp. 110 ◽  
Author(s):  
JG Bolton ◽  
GJ Stanley ◽  
OB Slee
Keyword(s):  
Flux Density ◽  
Radio Frequencies ◽  
The Individual ◽  
Galactic Radiation

One hundred and four discrete sources have been found from a survey covering declinations +50 to ?50�. The individual sources are compared in position and flux density with those of previous surveys. The observed distribution shows the concentration of sources of all brightnesses to the galactic equator found by Brown and Hazard (1953) and the concentration of the bright sources to the equator found by Mills (1952a, 1952b, 1952c).

Open-ended MEMS Probes for Dielectric Spectroscopy of Biological Cells at Radio Frequencies

PIERS Online ◽  
2009 ◽  
Vol 5 (3) ◽  
pp. 251-255 ◽  
Author(s):  
Hsin-Hung Li ◽  
Jen-Yu Jao ◽  
Ming-Kun Chen ◽  
Ling-Sheng Jang ◽  
Yi-Chu Hsu
Keyword(s):  
Dielectric Spectroscopy ◽  
Biological Cells ◽  
Radio Frequencies

scholarly journals ASKAP observations of multiple rapid scintillators reveal a degrees-long plasma filament

2021 ◽  
Vol 502 (3) ◽  
pp. 3294-3311
Author(s):  
Yuanming Wang ◽  
Artem Tuntsov ◽  
Tara Murphy ◽  
Emil Lenc ◽  
Mark Walker ◽  
...  
Keyword(s):  
Physical Properties ◽  
Angular Width ◽  
Scattering Medium ◽  
Central Frequency ◽  
Linear Arrangement ◽  
Plasma Filament ◽  
Kinematic Models ◽  
Tidal Stream ◽  
First Time ◽  
Insight Into

ABSTRACT We present the results from an Australian Square Kilometre Array Pathfinder search for radio variables on timescales of hours. We conducted an untargeted search over a 30 deg2 field, with multiple 10-h observations separated by days to months, at a central frequency of 945 MHz. We discovered six rapid scintillators from 15-min model-subtracted images with sensitivity of $\sim\! 200\, \mu$Jy/beam; two of them are extreme intra-hour variables with modulation indices up to $\sim 40{{\ \rm per\ cent}}$ and timescales as short as tens of minutes. Five of the variables are in a linear arrangement on the sky with angular width ∼1 arcmin and length ∼2 degrees, revealing the existence of a huge plasma filament in front of them. We derived kinematic models of this plasma from the annual modulation of the scintillation rate of our sources, and we estimated its likely physical properties: a distance of ∼4 pc and length of ∼0.1 pc. The characteristics we observe for the scattering screen are incompatible with published suggestions for the origin of intra-hour variability leading us to propose a new picture in which the underlying phenomenon is a cold tidal stream. This is the first time that multiple scintillators have been detected behind the same plasma screen, giving direct insight into the geometry of the scattering medium responsible for enhanced scintillation.

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