scholarly journals Intensity Distribution of Interplanetary Scintillation at 408 MHz

1975 ◽  
Vol 28 (5) ◽  
pp. 621 ◽  
Author(s):  
RG Milne
Keyword(s):  
Flux Density ◽  
Intensity Distribution ◽  
Small Diameter ◽  
Point Sources ◽  
Radio Sources ◽  
Interplanetary Scintillation ◽  
The Core ◽  
Intensity Fluctuations

It is shown that interplanetary scintillation of small-diameter radio sources at 408 MHz produces intensity fluctuations which are well fitted by a Rice-squared. distribution, better so than is usually claimed. The observed distribution can be used to estimate the proportion of flux density in the core of 'core-halo' sources without the need for calibration against known point sources.

scholarly journals Observations of interplanetary scintillation in China

2012 ◽  
Vol 8 (S294) ◽  
pp. 487-488
Author(s):  
Li-Jia Liu ◽  
Bo Peng
Keyword(s):  
Solar Wind ◽  
Interplanetary Medium ◽  
Interplanetary Space ◽  
Solar Wind Speed ◽  
Small Diameter ◽  
Primary Source ◽  
Radio Sources ◽  
The Sun ◽  
Interplanetary Scintillation ◽  
The Earth

AbstractThe Sun affects the Earth in multiple ways. In particular, the material in interplanetary space comes from coronal expansion in the form of solar wind, which is the primary source of the interplanetary medium. Ground-based Interplanetary Scintillation (IPS) observations are an important and effective method for measuring solar wind speed and the structures of small diameter radio sources. In this paper we will discuss the IPS observations in China.

scholarly journals 8·8 GHz Radio Observations of 12 Suggested Supernova Remnants

1973 ◽  
Vol 26 (3) ◽  
pp. 379 ◽  
Author(s):  
JR Dickel ◽  
DK Milne ◽  
AR Kerr ◽  
JG Ables
Keyword(s):  
Flux Density ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Galactic Plane ◽  
Small Diameter ◽  
Radio Sources ◽  
Radio Observations ◽  
Frequency Measurements ◽  
Thermal Spectrum

Brightness distributions and flux densities at 8�8 GHz are presented for 12 small-diameter radio sources near the galactic plane. Each of these sources has been classified at one time or another as a supernova remnant. For one source, G295� 2 - 0�6, the flux density at 8�8 GHz confirms the thermal spectrum suggested by lower frequency measurements and indicates that it is not a supernova remnant. Another source, G309� 6+ 1�7, is thought to be extragalactic.

scholarly journals 5000 MHz Flux Densities and Spectra for 325 Small-diameter Radio Sources at Low Galactic Latitudes

1975 ◽  
Vol 28 (5) ◽  
pp. 633 ◽  
Author(s):  
JL Caswell ◽  
RF Haynes ◽  
DH Clark
Keyword(s):  
Flux Density ◽  
Small Diameter ◽  
Radio Sources ◽  
Density Measurements

Flux density measurements at 5000 MHz are presented for 325 of the small-diameter sources detected in the Molonglo 408 MHz galactic survey. By investigating the spectra we show that probably between 10 % and 15 % of the sources are galactic and the remainder extragalactic.

scholarly journals A Catalogue of Small-diameter Radio Sources Close to the Galactic Plane

1974 ◽  
Vol 27 (5) ◽  
pp. 713 ◽  
Author(s):  
DH Clark ◽  
DF Crawford
Keyword(s):  
Flux Density ◽  
Galactic Plane ◽  
Small Diameter ◽  
Hii Regions ◽  
Radio Sources ◽  
Galactic Radio

A catalogue of 'smaIl-diameter' galactic radio sources observed at a frequency of 408 MHz with the Molonglo radiotelescope is presented. The catalogue covers an area of 0�40 sr enclosed in the range [II = 190�-360�-50�, 1 bIll..;; 3�. The sources listed are those which show no significant broadening of the ~ 3' arc aerial beam. Small-diameter features bounded or confused by extended regions of emission are not included. A total of 513 sources are listed above a flux density of O' 6 Jy. While most of these are expected to be extragalactic, the list includes some known pulsars and small-diameter HII regions. The catalogue should form a useful search list for the identification of other such galactic objects.

Interplanetary Scintillation Studies at the Molonglo Radio Observatory

1972 ◽  
Vol 2 (2) ◽  
pp. 88-89
Author(s):  
R. G. Milne
Keyword(s):  
Radio Source ◽  
Radio Telescope ◽  
Interplanetary Medium ◽  
Small Diameter ◽  
Line Of Sight ◽  
Radio Sources ◽  
The Sun ◽  
Interplanetary Scintillation ◽  
Radio Observatory ◽  
Half Power

The structure of small diameter radio sources can be investigated by studying the scintillation of the source due to the interplanetary medium when the line of sight approaches the Sun. Observations of radio source scintillation are currently being undertaken with the separate arms of the 1 mile radio telescope at the Molonglo Observatory. The EW arm allows successive transit observations with three fan beams, 1′.4 EW by 4°.2 NS at 408 MHz, bandwidth 2.5 MHz. Sources transit the half-power points of each beam in 6 sec δ seconds of time (δ is the source declination). The NS arm gives eleven fan beams at neighbouring declination, 1′.5 sec Z NS by 4° EW (Z is the zenith angle). Complete transit of a NS beam takes 15 sec δ minutes.

Interplanetary Scintillation of Small Diameter Radio Sources

Nature ◽  
1964 ◽  
Vol 203 (4951) ◽  
pp. 1214-1217 ◽  
Author(s):  
A. HEWISH ◽  
P. F. SCOTT ◽  
D. WILLS
Keyword(s):  
Small Diameter ◽  
Radio Sources ◽  
Interplanetary Scintillation

Flux Densities at 8·87 GHz of 347 Small-diameter Radio Sources

1981 ◽  
Vol 34 (4) ◽  
pp. 471 ◽  
Author(s):  
AJ Shimmins ◽  
JG Bolton
Keyword(s):  
Flux Density ◽  
Integration Method ◽  
Small Diameter ◽  
Radio Sources ◽  
Density Scale

Flux densities at" 8�87 GHz (A = 3�4 cm) have been determined with the Parkes 64 m telescope for 347 radio sources, using an improved on-off integration method. The sources were selected from the Parkes 2700 MHz catalogue as those having estimated flux densities at 8�87 GHz greater than 0'5 Jy (= 0�5 x 1O- 26 Wm-2 Hz-I) and relatively small angular sizes. A total of 156 of the sources are identified with QSOs and 58 with galaxies, and 133 have not been optically identified. Of the 347 sources 101 have been previously measured at this frequency at Parkes. Some of these repeats were made to check variability and others to compare the flux density scale with that of previous measurements. The estimated accuracy of most of the measurements is � 0�034 Jy (r.m.s.) due to noise and confusion and 3�0 % due to other causes.

scholarly journals Large Bent Jets in the Inner Region of CSS

1996 ◽  
Vol 175 ◽  
pp. 71-72
Author(s):  
F. Mantovani ◽  
W. Junor ◽  
M. Bondi ◽  
L. Padrielli ◽  
W. Cotton ◽  
...  
Keyword(s):  
Velocity Structure ◽  
Radio Sources ◽  
Ambient Media ◽  
The Core ◽  
Gaseous Environment ◽  
Radio Jets ◽  
Large Size ◽  
Superluminal Motion ◽  
Inner Region ◽  
Quasars And Radio Galaxies

Recently we focussed our attention on a sample of Compact Steep-spectrum Sources (CSSs) selected because of the large bent radio jets seen in the inner region of emission. The largest distortions are often seen in sources dominated by jets, and there are suggestions that this might to some extent be due to projection effects. However, superluminal motion is rare in CSSs. The only case we know of so far is 3C147 (Alef at al. 1990) with a mildly superluminal speed of ≃ 1.3v/c. Moreover, the core fractional luminosity in CSSs is ≃ 3% and ≤ 0.4% for quasars and radio galaxies respectively. Similar values are found for large size radio sources i.e. both boosting and orientations in the sky are similar for the two classes of objects. An alternative possibility is that these bent-jet sources might also be brightened by interactions with the ambient media. There are clear indications that intrinsic distortions due to interactions with a dense inhomogeneous gaseous environment play an important role. Observational support comes from the large RMs found in CSSs (Taylor et al. 1992; Mantovani et al. 1994; Junor et al. these proc.) and often associated with strong depolarization (Garrington & Akujor, t.p.). The CSSs also have very luminous Narrow Line Regions emission, with exceptional velocity structure (Gelderman, t.p.).

scholarly journals Waves in Microstructured Conducting Sheath Helix Embedded Optical Guides with Chiral Nihility and Chiral Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
N. Iqbal ◽  
M. A. Baqir ◽  
P. K. Choudhury
Keyword(s):  
Boundary Conditions ◽  
Flux Density ◽  
Energy Flux ◽  
Pitch Angle ◽  
Electromagnetic Waves ◽  
The Core ◽  
Dispersion Behavior ◽  
Chiral Materials ◽  
Energy Flux Density

The paper deals with the sustainment of electromagnetic waves in circularly cylindrical optical guide with chiral nihility and chiral materials in the core and the clad sections, respectively. A perfectly conducting tightly wound helix is introduced at the core-clad interface. The eigenvalue relation for such a complex optical microstructured guide is deduced by applying suitable boundary conditions at the core-clad interface, and the dispersion behavior is analyzed by varying the pitch angle of helix. The sustainment of energy flux density in such optical guides is estimated under various structural conditions, and the density patterns in core-clad sections are anatomized analytically.

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