R. W. Clay

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Cosmic rays with energies above 10 18 eV are currently of considerable interest in astrophysics and are to be further studied in a number of projects which are either currently under construction or the subject of well-developed proposals. This paper aims to discuss some of the physics of such particles in terms of current knowledge and information from(More)
– 2 – Observations of the PSR B1259−63/SS2883 binary system using the CANGAROO-II Cherenkov telescope are reported. This nearby binary consists of a 48 msec radio pulsar in a highly eccentric orbit around a Be star, and offers a unique laboratory to investigate the interactions between the outflows of the pul-sar and Be star at various distances. It has(More)
The average mass composition of cosmic rays with primary energies between 10 17 and 10 18 eV has been studied using a hybrid detector consisting of the High Resolution Fly's Eye (HiRes) prototype and the MIA muon array. Measurements have been made of the change in the depth of shower maximum and the muon density as a function of energy. The results show(More)
Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrated a correlation between the arrival directions of cosmic rays with energy above 6 x 10(19) electron volts and the positions of active galactic nuclei (AGN) lying within approximately 75 megaparsecs. We rejected the hypothesis of an isotropic distribution of these(More)
Persons with mental illnesses who are released from jail or prison are at high risk of psychiatric decompensation and re-arrest. This paper describes an ACT jail linkage program for this population that won an American Psychiatric Association Gold Award (2001). Based on interviews with its first 24 participants, we illustrate how they experience factors(More)
Rapid radio intra-day variability (IDV) has been discovered in the southern quasar PKS 1257−326. Flux density changes of up to 40% in as little as 45 minutes have been observed in this source, making it, along with PKS 0405−385 and J1819+3845, one of the three most rapid IDV sources known. We have monitored the IDV in this source with the Australia(More)
The High Resolution Fly's Eye (HiRes) experiment is an air fluorescence detector which, operating in stereo mode, has a typical angular resolution of 0.6 • and is sensitive to cosmic rays with energies above 10 18 eV. HiRes is thus an excellent instrument for the study of the arrival directions of ultrahigh energy cosmic rays. We present the results of a(More)
We observed the unidentified TeV gamma-ray source HESS J1804−216 with the CANGAROO-III atmospheric Cerenkov telescopes from May to July in 2006. We detected very high energy gamma rays above 600 GeV at the 10σ level in an effective exposure of 76 hr. We obtained a differential flux of (5.0 ± 1.5 stat ± 1.6 sys) × 10 −12 (E/1 TeV) −α cm −2 s −1 TeV −1 with a(More)
Kepler's supernova, discovered in October 1604, produced a remnant that has been well studied observationally in the radio, infrared, optical, and X-ray bands, and theoretically. Some models have predicted a TeV gamma-ray flux that is detectable with current Imaging Cherenkov Atmospheric Telescopes. We report on observations carried out in 2005 April with(More)
We report on the status of the construction of an array of four 10 m atmospheric Cherenkov telescopes for gamma-ray astronomy, near Woomera, in South Australia – the CANGAROO-III project. The first telescope of this array is the upgraded version of the CANGAROO-II 7 m telescope and has been in operation since March 2000. The second telescope, an improved(More)