scholarly journals ATCA Radio Polarization Observations of NGC 1566 and NGC 1672

1994 ◽  
Vol 158 ◽  
pp. 358-360
Author(s):  
R. Beck ◽  
M. Ehle ◽  
R. F. Haynes ◽  
J. I. Harnett
Keyword(s):  
Radio Emission ◽  
Southern Hemisphere ◽  
Spiral Galaxies ◽  
Radio Continuum ◽  
Linearly Polarized ◽  
First Time ◽  
Compact Array

NGC 1566 and NGC 1672 have successfully been observed in radio continuum at 6 cm (26″ HPBW) with the Australia Telescope Compact Array (ATCA) using a 375-m array. We have detected for the first time with this telescope linearly polarized radio emission from two southern hemisphere spiral galaxies, NGC 1566 and NGC 1672.

scholarly journals Radio Continuum Maps of Southern Barred Spiral Galaxies

1996 ◽  
Vol 157 ◽  
pp. 239-241
Author(s):  
Margaret Mazzolini ◽  
Janice Long ◽  
Rachel Webster
Keyword(s):  
Spiral Galaxies ◽  
Radio Continuum ◽  
Nuclear Region ◽  
Barred Spiral Galaxies ◽  
Compact Array

AbstractA sample of southern spiral galaxies are being observed at 20 and 13 cm with the Australia Telescope Compact Array in order to look for examples of anomalous outflows from the nuclear region. In this paper we discuss the radio continuum maps of the three barred spiral galaxies observed to date.

scholarly journals Distribution of Non-Thermal Emission in Galaxies

1981 ◽  
Vol 94 ◽  
pp. 209-214 ◽  
Author(s):  
R. Sancisi ◽  
P.C. van der Kruit
Keyword(s):  
Spiral Galaxies ◽  
Angular Resolution ◽  
Thermal Emission ◽  
Radio Continuum ◽  
Continuum Emission ◽  
High Angular Resolution ◽  
Good Sensitivity ◽  
Physical Conditions ◽  
Large Samples ◽  
First Time

The properties of the radio continuum emission from spiral galaxies have been reviewed by Van der Kruit and Allen (1976) and by Van der Kruit (1978). In more recent years the major developments in the understanding of the radio continuum properties and the underlying physical conditions of galaxies have come from a number of surveys of large samples of objects. Some of these surveys (e.g. Hummel, 1980a) have good sensitivity and sufficiently high angular resolution to allow for the first time a clear separation of central sources and disk emission and a study of the properties of these components in a large number of galaxies. As a consequence some results already found, suggested or only suspected in previous detailed investigations of a limited number of objects are put on a firmer basis or entirely new aspects are revealed.

Preliminary Radio Continuum Maps of Three Spiral Galaxies

1996 ◽  
Vol 13 (2) ◽  
pp. 107-120 ◽  
Author(s):  
Margaret Mazzolini ◽  
Rachel Webster
Keyword(s):  
Spiral Galaxies ◽  
Radio Continuum ◽  
Continuum Structure ◽  
Compact Array

AbstractThe Australia Telescope Compact Array has been used in two 6 km configurations to make 12 hour observations of the radio continuum structure of three spiral galaxies at 1380 MHz and 2378 MHz. Radio maps of NGC 1792, 6300 and 1097 are presented here, as part of a survey to find examples of anomalous radio structures in spiral galaxies.

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 Non-thermal radio emission from Wolf-Rayet stars

1999 ◽  
Vol 193 ◽  
pp. 59-60
Author(s):  
Jessica M. Chapman ◽  
Claus Leitherer ◽  
Bärbel Koribalski
Keyword(s):  
Radio Emission ◽  
Radio Continuum ◽  
Continuum Emission ◽  
The Sun ◽  
Limited Sample ◽  
Thermal Radio ◽  
Thermal Radio Emission ◽  
Compact Array

We have used the Australia Telescope Compact Array to search for radio continuum emission at λ 3, 6, 13 and 20 cm from a distance-limited sample of 36 southern Wolf-Rayet stars within 3 kpc of the Sun. The observations were taken between 1994 and 1997. Radio continuum emission has been detected from 16 sources at 3 cm. Of these 11 sources were detected at 6 cm, seven sources were detected at 13 cm and 2 sources were detected at 20 cm (Chapman et al. 1999).

scholarly journals The Large Scale Distribution of Radio Continuum in E and SO Galaxies

1978 ◽  
Vol 77 ◽  
pp. 49-55
Author(s):  
R.D. Ekers
Keyword(s):  
Radio Emission ◽  
Radio Source ◽  
Large Scale ◽  
Spiral Galaxies ◽  
Elliptical Galaxy ◽  
Elliptical Galaxies ◽  
The Other ◽  
Radio Continuum ◽  
Radio Structure ◽  
Similar Morphology

If we look at the radio properties of the nearby ellipticals we find a situation considerably different from that just described by van der Kruit for the spiral galaxies. For example NGC 5128 (Cen A), the nearest giant elliptical galaxy, is a thousand times more powerful a radio source than the brightest spiral galaxies and furthermore its radio emission comes from a multiple lobed radio structure which bears no resemblance to the optical light distribution (e.g. Ekers, 1975). The other radio emitting elliptical galaxies in our neighbourhood, NGC 1316 (Fornax A), IC 4296 (1333–33), have similar morphology. A question which then arises is whether at lower levels we can detect radio emission coming from the optical image of the elliptical galaxies and which may be more closely related to the kind of emission seen in the spiral galaxies.

scholarly journals CPC2 Reduction with Hipparcos and Proper Motions in The Southern Hemisphere

1998 ◽  
Vol 11 (1) ◽  
pp. 551-551
Author(s):  
N. Zacharias ◽  
M.I. Zacharias ◽  
C. de Vegt ◽  
C.A. Murray
Keyword(s):  
Southern Hemisphere ◽  
Systematic Errors ◽  
Reference Star ◽  
Proper Motions ◽  
Positional Accuracy ◽  
Star Catalog ◽  
Naval Observatory ◽  
Celestial Reference System ◽  
First Time ◽  
Better Than

The Second Cape Photographic Catalog (CPC2) contains 276,131 stars covering the entire Southern Hemisphere in a 4-fold overlap pattern. Its mean epoch is 1968, which makes it a key catalog for proper motions. A new reduction of the 5687 plates using on average 40 Hipparcos stars per plate has resulted in a vastly improved catalog with a positional accuracy of about 40 mas (median value) per coordinate, which comes very close to the measuring precision. In particular, for the first time systematic errors depending on magnitude and color can be solved unambiguously and have been removed from the catalog. In combination with the Tycho Catalogue (mean epoch 1991.25) and the upcoming U.S. Naval Observatory CCD Astrograph Catalog (UCAC) project proper motions better than 2 mas/yr can be obtained. This will lead to a vastly improved reference star catalog in the Southern Hemisphere for the final Astrographic Catalogue (AC) reductions, which will then provide propermotions for millions of stars when combined with new epoch data. These data then will allow an uncompromised reduction of the southern Schmidt surveys on the International Celestial Reference System (ICRS).

scholarly journals High-Efficiency Polarizer Reflectarray Antennas for Data Transmission Links from a CubeSat

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1802
Author(s):  
Eduardo Martinez-de-Rioja ◽  
Daniel Martinez-de-Rioja ◽  
Rafael López-Sáez ◽  
Ignacio Linares ◽  
Jose A. Encinar
Keyword(s):  
Circular Polarization ◽  
Data Transmission ◽  
High Efficiency ◽  
High Gain ◽  
Dual Band ◽  
Left Handed ◽  
Linearly Polarized ◽  
Flat Profile ◽  
First Time ◽  
Collimated Beam

This paper presents two designs of high-efficiency polarizer reflectarray antennas able to generate a collimated beam in dual-circular polarization using a linearly polarized feed, with application to high-gain antennas for data transmission links from a Cubesat. First, an 18 cm × 18 cm polarizer reflectarray operating in the 17.2–22.7 GHz band has been designed, fabricated, and tested. The measurements of the prototype show an aperture efficiency of 52.7% for right-handed circular polarization (RHCP) and 57.3% for left-handed circular polarization (LHCP), both values higher than those previously reported in related works. Then, a dual-band polarizer reflectarray is presented for the first time, which operates in dual-CP in the frequency bands of 20 GHz and 30 GHz. The proposed antenna technology enables a reduction of the complexity and cost of the feed chain to operate in dual-CP, as a linear-to-circular polarizer is no longer required. This property, combined with the lightweight, flat profile and low fabrication cost of printed reflectarrays, makes the proposed antennas good candidates for Cubesat applications.

Radio Continuum Emission from Sculptor Galaxies

1986 ◽  
Vol 6 (3) ◽  
pp. 325-329 ◽  
Author(s):  
J . I. Harnet
Keyword(s):  
Radio Emission ◽  
Blue Light ◽  
Hii Regions ◽  
Radio Continuum ◽  
Radial Dependence ◽  
Continuum Emission ◽  
Upper Limits ◽  
Peak Flux

AbstractThe five major members of the Sculptor Group of galaxies and NGC 45 have been observed with the Molonglo observatory synthesis telescope. NGC 247 and NGC 300 were not detected and upper limits to their 843 MHz flux densities are given. Radio emission from NGC 7793 is discussed with particular attention to its morphology, radial dependence compared with that of the blue light and possible coincidences between HII regions and 843 MHz peak flux densities.

ECTOMYCORRHIZAL FUNGI AND NON-AGARICOID BASIDIOMYCETOUS MACROMYCETES OF THE FALKLANDS

2012 ◽  
Vol 69 (2) ◽  
pp. 219-238 ◽  
Author(s):  
R. Watling
Keyword(s):  
Southern Hemisphere ◽  
Ectomycorrhizal Fungi ◽  
Falkland Islands ◽  
The World ◽  
First Time

Fifty-one species of basidiomycetes are recorded from the Southern Atlantic archipelago of the Falkland Islands. Several other fungi are discussed in the light of these findings. Some of these fungi are recorded for the first time from the Falklands and especially from some of the smaller islands of the group adjacent to West and East Falkland. The world distributions of the fungi dealt with in this compilation, particularly in the southern hemisphere, are given where they are known. Comments are made on the possible reasons for the occurrence of the species in the Falklands, especially the ectomycorrhizal taxa.

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