The Square Kilometre Array (SKA)

Abstract:

In 1994 June-July we obtained nearly concurrent measurements of Cyg X-3 in hard X-rays and the infrared, using the OSSE instrument on GRO and the UKIRT. OSSE made a high significance measurement of the hard X-ray (> 50 keV) orbital light curve. Five days after the end of the OSSE observations we obtained a good IR /f-band light curve from data covering one orbit of Cyg X-3. Measurements of the light curve phase and shape probe the geometry of the system and the physics of radiation production and scattering. We determined for the first time that the light curve phases are consistent at these two different wavelengths. The light curve shapes were both marginally inconsistent (at about the 0.2% level) with the canonical soft X-ray shape measured by EXOSAT in 1983-1985. Underlying variations in DC IR flux and flaring during the observation make it difficult to draw unambiguous conclusions; more observations, with better IR coverage, are needed.

Abstract:

This paper summarizes Isothermal Remanence (IRM300mT) measurements from Holocene ice-core samples from two contrasting glaciological regimes: (i) the Greenland ice sheet and (ii) a Himalayan glacier. Cores had been previously characterized in terms of chronologies, geochemistry and, for the Himalayan core, microparticle concentrations. Six samples from the Greenland 20-D ice core from the time period AD 1876-1983 did not yield magnetic measurements above instrumental noise-level. Significant Isothermal Remanence measurements (IRM300mT) were obtained from some levels in the Himalayan ice core. Scanning electron microscopy and EDAX analyses indicate weathered crustal material. The techniques used require ice-core samples with relatively high dust loadings and/or larger volume ice samples.