We use state-of-the-art chemical models to track the cosmic evolution of the CNO isotopes in the interstellar medium of galaxies, yielding powerful constraints on their stellar initial mass function (IMF). We re-assess the relative roles of massive stars, asymptotic giant branch (AGB) stars and novae in the production of rare isotopes such as 13C, 15N, 17O and 18O, along with 12C, 14N and 16O. ...

A method has been developed for performing autonomous Lunar orbit determination based on measurements of the times at which stars set behind or rise above the Lunar limb. This system is being developed as a possible technology for use in the Lunar exploration initiative because it enables increased autonomy of operations near the Moon. The system consists of a specially modified star camera and...

The spectra of disc accreting neutron stars generally show complex curvature, and individual components from the disc, boundary layer and neutron star surface cannot be uniquely identified. Here we show that much of the confusion over the spectral form derives from inadequate approximations for comptonization and for the iron line. There is an intrinsic low energy cutoff in comptonised spectra ...

Rich clusters of galaxies are interesting as the most massive gravitationally bound objects in the Universe. Although containing only about 1 % of all galaxies, they provide an environment for the formation and evolution of galaxies that is unique, and in many regards, the population of galaxies seen today in rich clusters di ers from that found in the eld. We therefore propose to complement th...

Optical imaging is a valuable means of observing upper atmospheric structures, but tropospheric cloud cover and lack of automated means of data analysis present significant barriers to operational use of data from ground-based optical instruments. We have developed several concepts for identification and tracking of equatorial plasma depletions in all-sky imager data under realistic conditions ...

As a first step towards understanding the angular momentum evolutionary history of black holes in merging black-hole/neutron-star binaries, we perform population synthesis calculations to track the distribution of accretion histories of compact objects in such binaries. We find that there are three distinct processes can possibly contribute to the black-hole spin magnitude: a birth spin for the...

Intermap’s across track interferometric synthetic aperture radar, called STAR-3i, entered commercial service in August, 1996. Even though the research phase was highly successful, considerable effort was still required to transform STAR-3i into a system that produced data that were of consistently high quality. Consideration has to be given to first surface and motion issues, as well as to the ...

We have studied the candidate optical counterparts and the stellar population in the star-forming complex around the bright ULX in the western part of the spiral galaxy NGC4559, using HST/WFPC2, XMM-Newton/Optical Monitor, and ground-based data. We find that the ULX is located near a small group of OB stars, but is not associated with any massive young clusters nor with any extraordinary massiv...