This paper addresses the issue of calibrating the Advanced Technology Solar Telescope for high-precision polarimetry, in particular of the optical train above the Gregorian station (where suitable calibration optics will be placed). Conventional techniques would not be adequate for this telescope given its large aperture. Here we explore two

We report spectroscopic observations of the earthshine reflected from the Moon. By applying our well-developed photometry methodology to spectroscopy, we are able to precisely determine the Earth's reflectance and its variation as a function of wavelength through a single night as the Earth rotates. These data imply that planned regular monitoring

The majority of High Mass X-ray Binaries (HMXBs) behave like X-ray pulsars, revealing that they contain a magnetised neutron star. Among the four HMXBs showing neither pulsations nor the characteristics of accreting black holes, there is the unusual HMXB 4U 2206+54. Here we present contemporaneous high-energy and radio observations of this system

Of the mechanisms proposed to bring gaseous fuel into the central starburst regions of a galaxy, non-axisymmetries in the gravitational potential set up by interactions or by bars are among the most promising. Nevertheless, direct observational evidence for a connection between interactions and bars on the one hand, and starburst (as well as AGN)

We perform N-body simulations of encounters between spherical systems surrounded by a spherical halo. Following a preceding paper with a similar aim, the initial systems include a spherical Jaffe model for the luminous matter and a Hernquist model for the halo. The merger remnants from this sample are mainly slowly rotating, prolate spheroids with

We report here on a survey of N-body simulations of encounters between spherical galaxies. Initial systems are isotropic Jaffe models. Different sets of mass ratios, impact parameters and orbital energies are studied. Both merger remnants and systems perturbed after a non-merging encounter are analysed and compared to real-life elliptical galaxies