Observations of 11 Radio Sources Near 55 MHz

Journal of the Franklin Institute, 1967

The research objectives of the Radio Astronomy Group may be broadly described as follows. 1. Studies of continuum emission of extraterrestrial radio sources. The antenna facilities of the Haystack Microwave Research Facility, Lincoln Laboratory, M.I.T., have been used at 2-cm and 3.75-cm wavelengths to study temporal variations in the radio flux from quasi-stellar radio sources, l to map the brightness distribution in both the polarized and unpolarized components of the radiation from the strong radio 2 sources, and to determine the absolute flux from the radio sources Cassiopeia A and Taurus A. 3 This work continues and is being extended to other sources. The National Radio Astronomy Observatory interferometer, Green Bank, West Virginia, has been used for determining the brightness distribution of many galatic and extragalatic radio sources at 234 Mc/sec. Studies of Venus and Jupiter at wavelengths near the watervapor and ammonia resonances have been carried out on the 28-ft radio telescope of Lincoln Laboratory.4 A radiometer operating at 4-mm wavelength has been installed and tested on the 29-ft radio telescope at the Prospect Park Field Station of Air Force Cambridge Research Laboratories, and planetary observations are planned for the near future. 2. Studies of the radio spectrum of the interstellar medium. The spectral lines of OH have been the subject of extensive observations with the antennas of the Haystack Microwave Research and Millstone Radar Facility, Lincoln Laboratory, M.I.T., and the 140-ft radio telescope of the National Radio Astronomy Observatory, Green Bank, West Virginia. The studies during the past year have led to (a) the detection of circularly polarized OH emission, 5 (b) the detection of the isotopic species 018H,6 and the establishment of an upper limit to the angular size of the OH emitting regions of 15 seconds of arc.7 Interferometric observations are being extended by using the Millstone and Agassiz (Harvard) radio telescopes as an interferometer to determine the angular size of the emission regions. Searches for other spectral lines are concentrating on the CH radical, with a line expected near 3300 Mc/sec. 3. Study of microwave emission and absorption by the terrestrial atmosphere and

Monthly Notices of …, 2010

We present the full source catalogue from the Australia Telescope 20 GHz (AT20G) Survey. The AT20G is a blind radio survey carried out at 20 GHz with the Australia Telescope Compact Array (ATCA) from 2004 to 2008, and covers the whole sky south of declination 0 • . The AT20G source catalogue presented here is an order of magnitude larger than any previous catalogue of high-frequency radio sources, and includes 5890 sources above a 20 GHz flux-density limit of 40 mJy. All AT20G sources have total intensity and polarisation measured at 20 GHz, and most sources south of declination −15 • also have near-simultaneous flux-density measurements at 5 and 8 GHz. A total of 1559 sources were detected in polarised total intensity at one or more of the three frequencies.

2006

Peter Barnes (U Sydney), Kate Brooks (ATNF), Michael Burton (UNSW), Maria Cunningham (UNSW), John Dickey (U Tasmania), Phil Edwards (ISAS), Ron Ekers (ATNF), Yasuo Fukui (U Nagoya), Annie Hughes (Swinburne U), Ilana Klamer (U Sydney / ATNF), Vincent Minier (CEA Saclay), Erik Mueller (ATNF), Juergen Ott (ATNF), Bob Sault (ATNF), Mark Thompson (U Hertfordshire), Andrew Walsh (UNSW), Tony Wong (UNSW / ATNF).

Astronomy Reports, 2009

We present the results of our observations of compact extragalactic radio sources near the north celestial pole (+75 • ≤ δ ≤ +88 • ) obtained on the RATAN-600 radio telescope. Our sample consists of 51 radio sources with spectra that are either flat or inverted (growing toward shorter wavelengths) and with flux densities at 1.4 GHz S ν ≥ 200 mJy. We observed the sources at 1-21.7 GHz. Multi-frequency instantaneous spectra are presented for 1999-2007. We observed 33 of our sample source daily for 30 days in August 2007. As a result, we revealed 15 objects exhibiting rapid variations on time scales of a day. The multi-frequency instantaneous spectra of these sources indicate that radio flux variations on one-day timescales are characteristic of objects of various spectral types. More than half the sources exhibiting rapid variations demonstrate a growth in the variability amplitude with increasing frequency. For some of the objects, the variability amplitude is virtually independent of frequency.

Astronomy Reports, 2009

We present classifications, optical identifications, and radio spectra for eight radio sources from three flux-density-complete samples in the following declination ranges: 4 • −6 • (B1950), S 3.9 > 200 mJy; 10 • −12 • 30 (J2000), S 4.85 > 200 mJy; 74 • −75 • (J2000), S 4.85 > 100 mJy. For all these samples, the right ascensions are 0 h −24 h and the Galactic latitudes, |b| > 15 • . Our optical observations at 4000−7500Å were made with the 6-m telescope of the Special Astrophysical Observatory; we also observed at 0.97−21.7 GHz with the RATAN-600 radio telescope of the Special Astrophysical Observatory. We classify four of the objects as quasars and four as galaxies. Five of the radio sources have power-law spectra at 0.97−21.7 GHz, while two objects have flat spectra. The quasar J2358+0430 virtually did not vary during 23 years.

2004

This was a joint initiative of Commissions 40 (Radio Astronomy) and 41 (History of Astronomy), and as such the new WG comes under the umbrella of both Commissions and Divisions X and XII. Coincident with the formation of the WG at the General Assembly were 1.5 days of meetings about the history of radio astronomy, organised jointly by Commissions 40 and 41. Given Australia’s pioneering efforts in international radio astronomy, it was only natural that such sessions should form part of the program at the Sydney GA, and it was pleasing to see that they drew capacity audiences. Science Meeting 2, on “The Early Development of Australian Radio Astronomy”, ran all day on July 21, and attracted the following oral and poster papers:

The Emergence of Astrophysics in Asia, 2017

Between 1945 and 1950 New Zealand and New Zealand-based scientists hosted or initiated no fewer than five different radio astronomy projects, during the formative years of international radio astronomy. Four of these focused on solar radio emission, while the fifth was related to discrete sources (which, initially, were known as ‘radio stars’). One of the solar projects involved the independent discovery of solar radio emission; another project resulted in one of the world’s first graduate theses on solar radio astronomy; and a third solar project saw the publication of a paper in Nature, the first by a New Zealand astronomer. The sole non-solar project was mounted by two scientists from the Australian CSIR’s Division of Radiophyiscs, who successfully used observations made in New Zealand to identify optical correlates for three different ‘radio stars’, and show that they were in no way associated with stars (indicating that the term was a misnomer).

Journal of Astronomical History and Heritage, 2005

Bruce Sleeis one of the pioneersofradio astronomy. After recording solar emission during World War II, he joined what was then the Council of Scientific and Industrial Research's Division of Radiophysics in Sydney, Australia, and went on to make important contributions to Solar System, Galactic and extra-galactic astronomy. Since. his retirement, in 1989, he has continued his research as an Honorary Fellow of the Australia Telescope National Facility, Now in his early 80s, Bruce Slee is one of the few radio astronomy pioneers of the 1940swho is still actively contributing to astrophysics. This issue of the JoumaJ of A stronomical History and Heritage (JAH 2), and the two that will follow it, are a tribute to this quietly-spoken scientist and his remarkable 60-year involvement in radio astronomy.

Monthly Notices of the Royal Astronomical Society, 1999

A new sample of very powerful radio galaxies is defined from the Molonglo Reference Catalogue, according to the criteria S 408 MHz . 5 JyY 2308 # d # 108 and jbj $ 108. The sample is selected to have similar properties to the northern 3CR revised sample, and to be visible to a combination of existing northern telescopes such as the Very Large Array radio interferometer and large southern hemisphere telescope facilities. The sample contains 178 sources, of which spectroscopic redshifts are available in the literature for 128. For the remaining 50 sources, new radio imaging, optical imaging and spectroscopic observations are presented to identify the host galaxies and determine their redshifts. With these new observations the total sample is 100 per cent optically identified and redshifts are available for 174 (98 per cent) of the sources. The sample consists of one starburst galaxy, one Seyfert galaxy, 127 radio galaxies and 49 quasars. Basic properties of the sample, such as the distributions of the quasar and radio-galaxy populations in redshift and their locations on the radio power versus linear size P 2 D diagram, show no significant differences from the revised 3CR sample. The equatorial location and the high spectroscopic completeness of this sample make it a valuable resource for detailed studies of the nature and environments of these important objects with the new generation of southern hemisphere telescopes.

The Astronomical Journal, 2005

We present a complete sample of megaparsec-size double radio sources compiled from the Sydney University Molonglo Sky Survey (SUMSS). Almost complete redshift information has been obtained for the sample. The sample has the following defining criteria: Galactic latitude |b| > 12. • 5, declination δ < −50 • and angular size > 5 ′. All the sources have projected linear size larger than 0.7 Mpc (assuming H o = 71 km s −1 Mpc −1). The sample is chosen from a region of the sky covering 2100 square degrees. In this paper, we present 843-MHz radio images of the extended radio morphologies made using the Molonglo Observatory Synthesis Telescope (MOST), higher resolution radio observations of any compact radio structures using the Australia Telescope Compact Array (ATCA), and low resolution optical spectra of the host galaxies from the 2.3-m Australian National University (ANU) telescope at Siding Spring Observatory. The sample presented here is the first in the southern hemisphere and significantly enhances the database of known giant radio sources. The giant radio sources with linear size exceeding 0.7 Mpc have an abundance of (215 Mpc) −3 at the sensitivity of the survey. In the low redshift universe, the survey may be suggesting the possibility that giant radio sources with relict lobes are more numerous than giant sources in which beams from the centre currently energize the lobes.