γ Per looks like an unexceptional composite–spectrum binary, and has habitually been classified as G8 III+A3 V. Nevertheless, previous studies have produced conflicting results, of component masses that are uncomfortably high, or luminosities that are too large, or (most recently) showing that there is nothing abnormal about the components after all. However, new high-precision CCD spectroscopy and isolation of the secondary spectrum finds that mass of the giant is 3.9 M ⊙, which is indeed greater than would be expected from its published spectral type, and that both components have somewhat enhanced luminosities, thus re-opening the question of the origin and evolution of this somewhat unusual system.

I review the potential for observing cosmic re-ionization using the HI 21 cm line.

We analyzed a new photometry of this well-known Algol-like eclipsing binary together with old photoelectric measurements with the aim of better understanding of its orbital period changes and short-time light variations modulating the mean light curve. The analysis has been done by the new method based on the combination of the principal component analysis and robust regression. New spectroscopic observations and radial-velocity curve are also presented.

Galaxies in groups and clusters often experience strong tidal forces from its neighbors, expelling a significant amount of matter (stars and gas) to the surrounding environment, giving rise to ‘tidal debris’ features. We present the first experiments in a program of identification of substructures of extragalactic tidal debris elements in images from the HST archive, using wavelet-based multiresolution analysis. Tidal structures in two compact groups of galaxies, HCG 79 (Seyfert's Sextet) and HCG 92 (Stephan's Quintet) have been analyzed so far.

Fe K emission line is a powerful probe of the inner part of an accretiondisk. We analyze X-ray spectra of 43 Palomar-Green (PG) quasars takenfrom Boroson & Green (1992) observed with XMM-Newton and make anaveraged Fe K line profile. We studythe Eddington ratio dependence of the Fe K line profile. The width ofthe Fe line becomes broader (σ=0.1 to 0.7 keV) and its peak energy becomes higher (6.4 to 6.8 keV) as the Eddington ratio getslarger.

These results indicate that the physical state of the accretiondisk, such as the geometrical structure and/or ionization state, changes with the Eddington ratio.

Major mergers of gas-rich galaxies, each comparable in mass to the Milky Way, are rare at the present epoch. These events were readily identifed, however, two decades ago in far-infrared sky surveys (Soifer et al. 1986, 1987). Removal of the dust enshrouding these starbursts was almost immediately proposed as an evolutionary path to quasar formation (Sanders 1988). Recent measurements of the stellar velocity dispersion, rotation speed, and stellar surface brightness profile of these mergers suggest ULIRGs are indeed progenitors of field elliptical galaxies (Genzel et al. 2001; Tacconi et al. 2002).

We attempt to provide new insights into the kinematics of narrow-line regions (NLR) in Seyfert galaxies and quasars, the understanding of which, as well as of their intrinsic 3D morphology, is still rather limited. Motivated by the rise of the integral-field spectroscopy, capable of mapping full 2D velocity fields, and by our observational projects on NLRs (see e.g. Stoklasová et al., this volume) we have developed a computer code producing 2D kinematical maps resulting from projections of various gas geometries and velocity fields.

The standard mixing length model of convection is ill behaved at the centre of a star since the pressure scale height Hp=P/(ρg)→∞ as r→0, and the convective flux remains non zero at r=0. We propose a modifcation of this model of convection that has the correct behaviour in the central regions of a star and smoothly changes to the standard MLT away from the centre.

The formation of special binaries in a globular cluster is regulated by the total encounter rate γ in the cluster, but their life expectancy by the number of encounters γ that one system experiences. The orbital periods indicate whether a neutron star or white dwarf entered a binary via direct collision, via tidal capture, or via exchange encounter. The numbers of X-ray binaries with a neutron star scales with γ. Magnetically active binaries (including blue stragglers) are formed via evolution of primordial binaries, and their numbers scale with the cluster mass. Cataclysmic variables are formed by stellar encounters or via evolution of a primordial binary in clusters with high and low central density, respectively.

It is great privilege for me to welcome so many of you to Prague, or Praha as we call our capital in Czech.

We have been witnessing a very rapid development of observational techniques over the past few decades, leading to many exciting discoveries, quite often in the field of extragalactic research. I sometimes sense the tendency to consider the studies of binaries and stars in general as exhausted topics. However, we all know that the better our real and deep understanding of the principal sources of radiative energy in the Universe becomes, the safer will be the ground for studies of all higher hierarchical systems.

In 1905, Henri Poincaré predicted the existence of gravitational waves and assumed their speed equal to the speed of light. If additionally the gravitational aberration would have the same magnitude as the aberration of light, we would observe several paradoxical phenomena. For instance, the orbit of two bodies would be unstable, since two attractive forces arise that are not in line and hence form a couple. This will be modelled by a nonautonomous system of ordinary differential equations with delay. In fact, any positive value of the gravitational aberration increases the angular momentum of such a system and this may contribute to the expansion of the universe. We found a remarkable coincidence between the Hubble constant and the increasing distance of the Moon from the Earth.

In 2000, Carlip showed that in general relativity gravitational aberration is almost cancelled out by velocity–dependent interactions. We show how the actual value of the gravitational aberration can be obtained by measurement of a single angle at a suitable time t* corresponding to the perihelion of an elliptic orbit. We also derive an a priori error estimate that expresses how accurately t* has to be determined to obtain the gravitational aberration to a prescribed tolerance.

Atacama Submillimeter Telescope Experiment (ASTE) is a joint project between Japan and Chile for installing and operating a 10 m high precision telescope in the Atacama Desert in order to explore the southern sky through the submillimeter wavelength. We have achieved an accuracy of 19 μm (rms) for the main reflector surface and a stable radio pointing accuracy of about 2 arcsec (rms). A 350 GHz cartridge type SIS mixer receiver achieves good performance with a typical system noise temperature of 150 ~ 250 K in DSB and a main beam efficiency of 0.6 ~ 0.7 during winter nights.

A large scale CO(3-2) imaging survey of nearby galaxies using ASTE is now in progress. One of our goals is to compare our wide area CO(3-2) images with existing CO(1-0) data as well as distributions of massive star formation tracers (i.e., Hα and radio continuum emission) in order to understand the physical mechanism which controls the global star formation properties such as star formation efficiency. Initial CO(3-2) maps of some sample galaxies (M 83, NGC 604 in M 33, NGC 1672, & NGC 7130) are reported.

As well as reproducing observable features like solar granulation, 3D simulations can provide useful information for local or non-local stellar modeling. Examples include testing out the mixing length theory in the surface layers, providing the turbulent correction for stellar models of p-mode frequencies, testing eddy viscocity prescriptions used in tidal dissipation models and comparing different closures of higher order moments. Having validated the 3D code with the sun we applied it to other stars. For Procyon A the turbulence is about twice as strong as it is in the Sun (estimated by the peak root mean square vertical velocity which is about 6.5 km/s) and the granules are nearly an order of magnitude larger, with plumes regularly extending down 2-3 pressure scale heights below the surface of Procyon A. An interesting feature of the Procyon simulation is that the horizontal layers in the vicinity of the granules appear to radially pulsate in a quasi-periodic manner. This makes the superadiabatic layer move in and out over a distance of about half a pressure scale height in a time of about 20-30 minutes. This motion appears to be tied to the granulation but there may be other phenomena involved such as some kind of local kappa-mechanism confined to the granulation surface layers. We find similar behaviour in a simulation of an 11 Gyr subgiant sun. As the velocities are more like the sun (about 3km/s), the time period of the pulsation in the subgiant is 2-3 times longer than in Procyon A.

In the present work the results of an optical spectroscopy study of 8 galaxies projected in the central part of the A1367 cluster are reported. The observations were made using the 2.2 m. Guillermo Haro Telescope in Cananea (Mexico), and the Boller and Chivens spectrograph. A catalog of the optical positions of more than 100 galaxies in the cluster is presented. The redshifts of 7 galaxies were determined from their absorption systems, while for the remaining galaxy was obtained from its strong emission lines of H-alpha, S II, O III and H-beta. For one of the galaxies the emission redshift is z= 0.015, not showing absorptions lines at the cluster redshifts (z = 0.026), which argues that it is located between the observer and the A1367 cluster.

During its definition phase, ESA's Cornerstone mission Gaia was designed to perform extremely accurate photometry in 10 medium plus 5 broad bands and to collect about 90 epoch spectra with a resolving power of 11500 and a wavelength range 8480–8740Å (centered on the CaII triplet in the far red). Combining epoch photometry from the ground and the Hipparcos mission with ground-based spectra strictly simulating Gaia ones, we have investigated in a series of papers the performance expected from Gaia on SB2 EBs. We review here the results we obtained. The Gaia design is now under major revision, and its impact on EBs will be briefly addressed.

We discuss anisotropies in the near-IR background between 1 to a few microns. This background is expected to contain a signature of primordial galaxies. We have measured fluctuations of resolved galaxies with Spitzer imaging data and we are developing a rocket-borne instrument (the Cosmic Infrared Background ExpeRiment, or CIBER) to search for signatures of primordial galaxy formation in the cosmic near-infrared extra-galactic background.

I present a brief review of current work on dwarf galaxy age-metallicity relationships.

As found in Secco (2000, 2001), the presence of a (non-baryonic) dark halo in large-scale celestial objects, can induce a scale length on the luminous spheroid through the occurrence of an unexpected maximum in the virial potential energy (Clausius Virial, CV). The above mentioned investigations were grounded on two cored power law density profiles, but the same result is shown to hold for more refined and realistic models.

This paper describes a new initiative in support of the aim of Commission 46 of the IAU to develop and improve astronomy education at all levels throughout the world. This paper discusses the ideal specification of a facility to support basic astronomy within education programmes which are delivered to students who have access to the Internet. The available robotic telescopes are discussed against this specification and it is argued that the Bradford Robotic Telescope, uniquely, can support many thousands of users in the area of basic astronomy education, and the resource is free.

Access to the Internet is growing in the developing world and this is true in education programmes. This paper discusses the serious problems of delivering to large numbers of students a web based astronomy education programme supported by a robotic telescope as part of a general education. It examines the problems of this form of teaching for teachers who have little experience of working with IT and little knowledge of basic astronomy and proposes how such teachers can be supported.

The current system (http://www.telescope.org/) delivers astronomy education in the language, culture and traditions of England. The paper discusses the need to extend this to other languages, cultures and traditions, although for trainee teachers and undergraduates, it is argued that the current system provides a unique and valuable resource.

We investigate the possibility of detecting deep convection in the Sun by computing travel-time shifts induced by convective flows interacting with propagating waves. The convection zone is modeled using a velocity profile taken from an Anelastic convection simulation. We present results obtained from a ray calculation of travel-time shifts. We compare these results with a full 3D calculation of the wave-flow interaction.