Richard W. Hunstead

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Soft gamma-ray repeaters (SGRs) are 'magnetars', a small class of slowly spinning neutron stars with extreme surface magnetic fields, B approximately 10(15) gauss (refs 1 , 2 -3). On 27 December 2004, a giant flare was detected from the magnetar SGR 1806-20 (ref. 2), only the third such event recorded. This burst of energy was detected by a variety of(More)
Jupiter's nonthermal microwave emission, as measured by a global network of 11 radio telescopes, increased dramatically during the Shoemaker-Levy 9 impacts. The increase was wavelength-dependent, varying from approximately 10 percent at 70 to 90 centimeters to approximately 45 percent at 6 and 36 centimeters. The radio spectrum hardened (flattened toward(More)
We have observed the black hole candidate X-ray binary GX 339-4 at radio wavelengths before, during and after the 1998 high/soft X-ray state transition. We find that the radio emission from the system is strongly correlated with the hard X-ray emission and is reduced by a factor ≥ 25 during the high/soft state compared to the more usual low/hard state. At(More)
This is the third in a series of papers that present observations and results for a sample of 76 ultra-steep-spectrum radio sources designed to find galaxies at high redshift. Here we present multi-frequency radio observations, from the Australia Telescope Compact Array, for a subset of 37 galaxies from the sample. Matched resolution observations at 2.3,(More)
We present a comparison of the properties of a giant radio galaxy and the ambient intergalactic medium, whose properties are inferred from the large-scale distribution in galaxies. The double lobes of the radio galaxy MSH 05−22 are giant—1.8 Mpc projected linear size—and interacting with the environment outside the interstellar medium and coronal halo(More)
This is the second in a series of papers presenting observations and results for a sample of 76 ultra-steep-spectrum (USS) radio sources in the southern hemisphere designed to find galaxies at high redshift. Here we focus on the optical spectroscopy program for 53 galaxies in the sample. We report 35 spectroscopic redshifts, based on observations with the(More)
Using the Australia Telescope Compact Array we have detected CO (1-0) and CO (5-4) from TN J0924–2201 at z = 5.2, the most distant radio galaxy known to date. This is the second highest redshift detection of CO published so far. The CO (1-0) is 250 − 400km s −1 wide with a peak flux density of 520 ± 115 µJy beam −1 whilst the CO (5-4) line emission is 200 −(More)
We present the first results from a pilot study to search for distant radio galaxies in the southern hemisphere (δ < −32 •). Within a 360 deg 2 region of sky, we define a sample of 76 ultra–steep spectrum (USS) radio sources from the 843 MHz Sydney University Molonglo Sky Survey (SUMSS) and 1.4 GHz NRAO VLA Sky Survey (NVSS) radio surveys with α 1400 843 <(More)
Received ; accepted – 2 – ABSTRACT Measurements of Zn and Cr abundances in 18 damped Lyman α systems (DLAs) at absorption redshifts z abs = 0.692 − 3.390 (but mostly between z ≃ 2 and 3) show that metals and dust are much less abundant in high redshift galaxies than in the Milky Way today. Typically, [Zn/H] ≃ −1.2; as Zn tracks Fe closely in Galactic stars(More)