scholarly journals Australian Journal of Physics Astrophysical Supplements Number 22, May 1972

1972 ◽  
Vol 25 (3) ◽  
pp. 339
Author(s):  
REB Munro
Keyword(s):  
Radio Telescope ◽  
Australian Journal ◽  
Radio Sources ◽  
Spectral Indices ◽  
The Mean

Observations at 408 MHz of radio sources from the 4C catalogue. IV. Declination range 20� to 0�. By R. E. B. Munro Abstract. Radio positions and flux densities measured at 408 MHz with the Molonglo radio telescope are given for 1392 sources from the Fourth Cambridge catalogue in the declination range 20� to 0�. The mean spectral indices between 178 and 408 MHz are also considered in the light of these improved flux densities.

A statistical method for analysing observations of faint radio stars

1957 ◽  
Vol 53 (3) ◽  
pp. 764-773 ◽  
Author(s):  
P. A. G. Scheuer
Keyword(s):  
Statistical Method ◽  
Frequency Distribution ◽  
Radio Telescope ◽  
Resolving Power ◽  
Continuous Recording ◽  
Radio Sources ◽  
Direct Relation ◽  
The Mean ◽  
Radio Stars

ABSTRACTThe observation of faint radio sources is often limited by the angular resolving power of the radio telescope, and not by its sensitivity. Continuous recording of the output from the receiving apparatus then produces a trace which always shows the sum of the effects of a number of sources in the reception pattern, instead of showing sources passing through the reception pattern one at a time. The apparent intensities of sources found on the records are affected by the presence of several other, fainter, sources in the reception pattern, and even the existence of many of the faint sources is doubtful. Counts of numbers of sources at given intensity levels are therefore unreliable.Any assumed number-intensity law for radio sources can, however, be tested by a method free from the uncertainties due to confusion between adjacent sources, using a direct relation between the number-intensity law and the frequency distribution of deflexions of various sizes on the observed records. The present paper shows the derivation of the relation between M (I) dI, the mean number of radio sources per steradian in the intensity interval dI, and P(D)dD, the probability that the deflexion D recorded at an arbitrary instant lies in the interval dD. Expressions for P(D) are worked out for some specific models of M (I); a comparison with observation has been given in an earlier paper (6).

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 Australian Journal of Physics Astrophysical Supplements

1972 ◽  
Vol 25 (6) ◽  
pp. 779 ◽  
Author(s):  
GA Day ◽  
JL Caswell ◽  
DJ Cooke
Keyword(s):  
Radio Telescope ◽  
Galactic Plane ◽  
Australian Journal ◽  
Radio Sources ◽  
Contour Maps ◽  
Half Power

The results of observations of the galactic plane in the longitude ranges 46� to 61� and 190� to 290� undertaken with the 64 m (210 ft) radio telescope of the Parkes Observatory are given in the form of contour maps and a list of 343 radio sources. At the observing frequency of 2700 MHz the half-power beamwidth was 8'�2 arc. Some individual sources are discussed in detail. The present results together with those already published complete the Parkes 11 cm survey of the galactic plane.

Positions of Radio Sources Measured with the One-Mile Radio Telescope

Nature ◽  
1966 ◽  
Vol 210 (5031) ◽  
pp. 22-23 ◽  
Author(s):  
E. A. PARKER ◽  
B. ELSMORE ◽  
J. R. SHAKESHAFT
Keyword(s):  
Radio Telescope ◽  
Radio Sources ◽  
The One

scholarly journals Low frequency radio counterparts of HESS J1731−347 a.k.a SNR G353.6−0.7

2017 ◽  
Vol 12 (S331) ◽  
pp. 201-205
Author(s):  
A. J. Nayana ◽  
Poonam Chandra
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Supernova Remnants ◽  
Low Frequency ◽  
High Energy ◽  
Spectral Indices ◽  
Thermal Radio Emission ◽  
Very High Energy ◽  
Γ Rays ◽  
Very High

AbstractHESS J1731−347 a.k.a. SNR G353.6−0.7 is one of the five known very high energy (VHE, Energy > 0.1 TeV) shell-type supernova remnants. We carried out Giant Metrewave Radio Telescope (GMRT) observations of this TeV SNR in 1390, 610 and 325 MHz bands. We detected the 325 and 610 MHz radio counterparts of the SNR G353.6−0.7 (Nayana et al. 2017). We also determined the spectral indices of individual filaments and our values are consistent with the non-thermal radio emission. We compared the radio morphology with that of VHE emission. The peak in radio emission corresponds to the faintest feature in the VHE emission. We explain this anti-correlated emission in a possible leptonic origin of the VHE γ-rays.

scholarly journals Magnetic Field Strengths of GPS Radio Sources

1999 ◽  
Vol 194 ◽  
pp. 324-326
Author(s):  
V. G. Panajyan
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Radio Sources ◽  
Spectral Indices ◽  
The Past ◽  
Spectrum Radio ◽  
Field Strengths

GHz peaked spectrum radio sources (GPS) are believed to be a subclass of compact steep spectrum radio sources (CSS) with high frequency spectral indices α < −0.5 (5 ˜ vα), linear sizes of pc to kpc scale and turnover spectra near 1GHz. Due to the work of many radioastronomers during the past two decades many properties of CSS and GPS radio sources at present are known (O'Dea,C.P. et al.1998, and references therein).

scholarly journals The spectra of radio sources

1959 ◽  
Vol 9 ◽  
pp. 297-304
Author(s):  
G. R. Whitfield
Keyword(s):  
Radio Sources ◽  
Spectral Indices ◽  
Recent Information ◽  
Larger Sample ◽  
Qualitative Picture

I have already reported on the spectra of 31 radio sources [1], but since then, new observations have become available, and, in addition, I have corrected my own 38-Mc/s measurements for a nonlinearity in the response of my receiver. The qualitative picture remains the same, but from the more recent information I have found values for the spectral indices of 85 sources, and have revised some of those given previously. From the larger sample of sources now available, it is possible to suggest some relationships of sufficient interest to warrant further investigation.

scholarly journals The Use of the RATAN-600 Radio Telescope in Astrometry

1986 ◽  
Vol 109 ◽  
pp. 169-171
Author(s):  
P. M. Afanasieva ◽  
V. A. Fomin ◽  
Yu K. Zverev ◽  
M. G. Mingaliev ◽  
V. N. L'Vov ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Resolving Power ◽  
Radio Sources

The RATAN-600 radio telescope (Kaidanovsky & al. 1972) was designed for solving various problems of astrophysics and radiophysics (Pariisky & al. 1972, Gelfreikh & al. 1972). Because of its high resolving power and large collecting area, this instrument can be used to measure accurate positions of radio sources.

scholarly journals LOFAR observations of the XMM-LSS field

2019 ◽  
Vol 622 ◽  
pp. A4 ◽  
Author(s):  
C. L. Hale ◽  
W. Williams ◽  
M. J. Jarvis ◽  
M. J. Hardcastle ◽  
L. K. Morabito ◽  
...  
Keyword(s):  
Large Scale ◽  
Angular Resolution ◽  
Low Frequency ◽  
Primary Beam ◽  
Electromagnetic Spectrum ◽  
Radio Sources ◽  
Spectral Indices ◽  
The North ◽  
True Source ◽  
Scale Calibration

We present observations of the XMM Large-Scale Structure (XMM-LSS) field observed with the LOw Frequency ARray (LOFAR) at 120–168 MHz. Centred at a J2000 declination of −4.5°, this is a challenging field to observe with LOFAR because of its low elevation with respect to the array. The low elevation of this field reduces the effective collecting area of the telescope, thereby reducing sensitivity. This low elevation also causes the primary beam to be elongated in the north-south direction, which can introduce side lobes in the synthesised beam in this direction. However the XMM-LSS field is a key field to study because of the wealth of ancillary information, encompassing most of the electromagnetic spectrum. The field was observed for a total of 12 h from three four-hour LOFAR tracks using the Dutch array. The final image presented encompasses ∼27 deg2, which is the region of the observations with a >50% primary beam response. Once combined, the observations reach a central rms of 280μJy beam−1at 144 MHz and have an angular resolution of 7.5 × 8.5″. We present our catalogue of detected sources and investigate how our observations compare to previous radio observations. This includes investigating the flux scale calibration of these observations compared to previous measurements, the implied spectral indices of the sources, the observed source counts and corrections to obtain the true source counts, and finally the clustering of the observed radio sources.

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