scholarly journals A Catalogue of Radio Sources Between Declinations ?20° and ?50°

1960 ◽  
Vol 13 (4) ◽  
pp. 676 ◽  
Author(s):  
BY Mills ◽  
OB Slee ◽  
ER Hill
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Apparent Size ◽  
Statistical Analyses ◽  
Radio Sources ◽  
Cross Type

A catalogue has been prepared of the radio sources observed between declinations _200 and _500 , using the Sydney cross-type radio telescope at a wavelength of 3�5 m ; a total of 892 sources is listed. This supplements an earlier catalogue in the declination zone + 10� to _20�. In addition to the positions and intensities of the sources, angular sizes of 50 of the strongest are given: several are found to have a size less than 15" arc. As before, identifications with bright optical objects have been sought, and a number of galaxies of apparently abnormal radio emission listed. Statistical analyses of the distribution of the radio sources give results very similar to those obtained using the earlier catalogue. \Vithin the uncertainty in the data, the distribution appears uniform in depth and there is a siguificantly greater number of sources of large apparent size than expected from chance blending effects.

scholarly journals A Catalogue of Radio Sources Between Declinations ?50° and ?80°

1961 ◽  
Vol 14 (4) ◽  
pp. 497 ◽  
Author(s):  
BY Mills ◽  
OB Slee ◽  
ER Hill
Keyword(s):  
Statistical Analysis ◽  
Radio Telescope ◽  
Small Area ◽  
Radio Sources ◽  
Low Weight ◽  
Cross Type

A catalogue has been prepared of the radio sources observed between declinations -50� and -80�, using the Sydney cross-type radio telescope at a wavelength of 3�5 m; a total of 219 sources is listed. This supplements the earlier catalogues for the declination ranges +10� to -20� and -20� to -50�. In addition to the positions and intensities of the sources, angular sizes of 42 of the strongest sources are given. As before, identifications with bright optical objects have been sought, and a number of possible identifications with emission nebulae and bright galaxies are listed. Because of the small area of sky covered by the present catalogue, the numbers of sources are small (compared with those in our earlier catalogues) so that the statistical analysis of their distribution has comparatively low weight.

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 Comparison of the Optical and Radio Reference Frames

1986 ◽  
Vol 7 ◽  
pp. 103-108 ◽  
Author(s):  
K. J. Johnston ◽  
Chr. de Vegt
Keyword(s):  
Radio Emission ◽  
Reference Frame ◽  
Radio Telescope ◽  
Reference Frames ◽  
Radio Sources ◽  
Large Array ◽  
Very Large Array ◽  
Extragalactic Radio Sources ◽  
Optical Reference ◽  
Lack Of Knowledge

The Very Large Array (VLA) has made possible the measurement of the precise positions of the radio emission associated with stars. This allows the direct comparison of the optical reference frame (FK4) with the radio reference frame which is defined by the quasi-absolute positions of extragalactic radio sources. This comparison is limited by the small number of bright stars that display detectable radio emission and the lack of knowledge of the precise coincidence of the radio emission with the optical photocenter of the star. Since the VLA is the most sensitive astrometrically capable radio telescope, positions of the largest number of stars north of declination -20 degrees can be measured. The accuracy of the positions on the extragalactic reference frame should approach a milliarcsecond.

scholarly journals Gain Measurements of Large Aerials Used in Interferometer and Cross?Type Radio Telescopes

1958 ◽  
Vol 11 (1) ◽  
pp. 70 ◽  
Author(s):  
AG Little
Keyword(s):  
Radio Telescope ◽  
Radio Sources ◽  
Radio Telescopes ◽  
Discrete Radio Sources ◽  
Cross Type

A method has been developed for measuring the gain of large interferometer and cross-type radio telescope aerials. Use is made of the strong discrete radio sources, whose intensity need not be known, to allow comparison of the gains of the aerials with that of a standard.

scholarly journals SPORADIC RADIO EMISSION OF SPACE OBJECTS AT LOW-FREQUENCIES

2021 ◽  
Vol 26 (2) ◽  
pp. 99-129
Author(s):  
V. V. Zakharenko ◽  
◽  
V. B. Ryabov ◽  
I. P. Kravtsov ◽  
K. Yu. Mylostna ◽  
...  
Keyword(s):  
Solar System ◽  
Radio Emission ◽  
Neutron Stars ◽  
Radio Telescope ◽  
Data Cleaning ◽  
Signal Extraction ◽  
Radio Frequency Interference ◽  
Radio Sources ◽  
Radio Interference ◽  
Characteristic Features

Purpose: The results of studies of sporadic radio emission of several types of space radio sources, including neutron stars and planets of the Solar System, are presented. The aim of this work is to review the latest achievements in the study of low-frequency radio emission of the Solar System planets and transient signals similar to pulsar pulses using the UTR-2 radio telescope. The importance of the development of the verification methods of the spaceborne radio emission in the study of sporadic signals from various sources is shown. Design/methodology/approach: The studies of sporadic signals of different nature are based on the common set of procedures for cleaning records from the terrestrial radio frequency interference (RFI) in the frequency-time pattern using the information on the nature of the particular type of sporadic radio emission, possible types of interference and signal distortion. Characteristic features of sporadic radio emission of different sources are given, and for each of them the optimal method of signal extraction is developed. The efficiency of the developed procedures for cleaning from noise using adjustable parameters is shown. This is done on the basis of observations of diverse types of space radio sources, such as lightnings in the atmospheres of planets, single pulses of neutron stars and sporadic radio emission of Jupiter. Findings: The developed methods of signal extraction detection in the presence of radio-interference have allowed obtaining the unique results such as: the distribution of the total intensity of single pulses of neutron stars depending on the galactic latitude; the automatic search of lightnings in the Saturn’s atmosphere in data due to the carefully elaborated RFI mitigation procedures, which made it possible to obtain the Saturn electrostatic discharge (SED) emission parameters based on the most complete set of events. Increased efficiency of the selection of Jupiter’s S-radiation signals despite the data corruption by the presence of radio-interference, which was reached due to the carefully chosen parameters of data cleaning procedures, have allowed us to detect short and intensive bursts, being the most informative for determining the physical parameters of radio emission in the area of their generation. Conclusions: The large effective area and high sensitivity of the UTR-2 radio telescope allow making the sporadic radio emission study with high temporal and frequency resolutions. Due to these factors we can apply a wide range of methods of space signals’ detection in the presence of terrestrial radio-frequency interference of natural and artificial origin. The data cleaning parameters allow accounting for the characteristic features of space signals and to obtain important and even unique scientific results. Key words: decameter wavelength range; UTR-2; sporadic radio emission; transients; lightning in the atmospheres of planets; Jupiter S-bursts

scholarly journals A Catalogue of Radio Sources Between Declinations +10° and ?20°

1958 ◽  
Vol 11 (3) ◽  
pp. 360 ◽  
Author(s):  
BY Mills ◽  
OB Slee ◽  
ER Hill
Keyword(s):  
Radio Telescope ◽  
Source Distribution ◽  
Radio Sources ◽  
Cross Type

A catalogue has been prepared of the radio sources observed between declinations +10� and ?20�, using the Sydney cross-type radio telescope at a wavelength of 3�5 m: a total of 1159 sources is listed in the area of 3�24 steradians. This supersedes an earlier catalogue of Mills and Slee in portion of the area, but the differences between the two are small. A number of new identifications with galaxies are suggested, and an analysis made of the statistics of the source distribution. It is concluded that cosmological effects displayed by the distribution, if present, are small. Possibilities are discussed of separating from this distribution the effects of the instrument, the finite angular sizes, and/or the physical clustering of the sources.

scholarly journals A survey of radio sources at 3.5-m wavelength

1959 ◽  
Vol 9 ◽  
pp. 498-506
Author(s):  
B. Y. Mills
Keyword(s):  
Radio Telescope ◽  
Radio Sources ◽  
Pencil Beam ◽  
Radio Frequency Radiation ◽  
Cassiopeia A ◽  
Highly Sensitive ◽  
Accurate Position ◽  
Cross Type ◽  
Frequency Radiation ◽  
Beam Instrument

Since their discovery in 1946, the discrete sources of radio-frequency radiation have provided some of the most difficult problems in radio astronomy. For their effective study, one requires a very highly sensitive radio telescope sufficiently precise for accurate position determination and with sufficient resolution to observe separately the detectable radio sources. These requirements led to the development of the Sydney 3.5-m Cross-type radio telescope, which is a pencil-beam instrument with a beamwidth of about 50 minutes of arc and a sensitivity such that under ideal conditions a source of intensity about 1/10,000 that of the strongest known source, Cassiopeia A, is just detectable.

scholarly journals Supernova Remnants as Radio Sources

1968 ◽  
Vol 21 (5) ◽  
pp. 739 ◽  
Author(s):  
MJL Kesteven
Keyword(s):  
Spectral Index ◽  
Radio Telescope ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Radio Sources ◽  
Evolutionary Path ◽  
Contour Maps ◽  
Galactic Sources ◽  
Cross Type

The results of a survey with the 1 mile Molonglo cross-type radio telescope of nonthermal galactic sources are discussed in terms of supernova remnant theories. The contour maps obtained indicate that most sources are consistent with a portion of a shell of emission. The results suggest that a remnant's spectral index is independent of its age. A supernova remnant evolutionary path is also derived, and compared with the path predicted by the various theories.

scholarly journals Some new observations relating to galactic radio sources and background structure

1964 ◽  
Vol 20 ◽  
pp. 107-114 ◽  
Author(s):  
E. R. Hill
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Milky Way ◽  
Angular Resolution ◽  
Spectral Information ◽  
Radio Sources ◽  
Background Structure ◽  
The Galaxy ◽  
Galactic Radio

A survey of the distribution of radio emission at wavelengths of 75 and 20 cm along an extensive section of the Southern Milky Way has recently been carried out by M. Komesaroff and myself using the 210-foot radio telescope at Parkes. The area surveyed ranges from lII = 280 to 355° and extends on the average to 6 degrees either side of the plane. The beamwidths of the aerial at 75 and 20 cm are 50 and 14 min arc respectively. Observations at the shorter wavelength offer a picture of this section of the Galaxy at considerably higher angular resolution than hitherto available, while the 75-cm observations are expected to make a useful contribution to our spectral information.

The GLEAM 4-Jy Sample: The brightest radio-sources in the southern sky

2019 ◽  
Vol 15 (S356) ◽  
pp. 375-375
Author(s):  
Sarah White
Keyword(s):  
Radio Emission ◽  
Active Galactic Nuclei ◽  
Visual Inspection ◽  
Low Frequency ◽  
Galactic Nuclei ◽  
Radio Sources ◽  
Relativistic Jets ◽  
The Galaxy ◽  
Murchison Widefield Array ◽  
Past Activity

AbstractLow-frequency radio emission allows powerful active galactic nuclei (AGN) to be selected in a way that is unaffected by dust obscuration and orientation of the jet axis. It also reveals past activity (e.g. radio lobes) that may not be evident at higher frequencies. Currently, there are too few “radio-loud” galaxies for robust studies in terms of redshift-evolution and/or environment. Hence our use of new observations from the Murchison Widefield Array (the SKA-Low precursor), over the southern sky, to construct the GLEAM 4-Jy Sample (1,860 sources at S151MHz > 4 Jy). This sample is dominated by AGN and is 10 times larger than the heavily relied-upon 3CRR sample (173 sources at S178MHz > 10 Jy) of the northern hemisphere. In order to understand how AGN influence their surroundings and the way galaxies evolve, we first need to correctly identify the galaxy hosting the radio emission. This has now been completed for the GLEAM 4-Jy Sample – through repeated visual inspection and extensive checks against the literature – forming a valuable, legacy dataset for investigating relativistic jets and their interplay with the environment.

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