Over the last four days, we have enjoyed a wide range of talks on developments in three dimensional spectroscopic techniques. The conference organizing committee are to be congratulated for the artful manner in which instrumental presentations were interleaved with talks on the scientific results from these instruments. The general thrust of most talks was to advance the versatility of traditional instruments either through the Jacquinot (throughput) advantage or through the multiplex advantage, or both. A number of groups have attempted to utilize the full aperture of scanning Fabry-Perot and Fourier Transform interferometers. Arguably, Fabry-Perot interferometers have a wider application at present, although imaging Fourier Transform devices appear to have finally arrived, at least in the near infrared.

Meridional flow results from slight deviations from the thermal wind balance. The deviations are relatively large in the boundary layers near the top and bottom of the convection zone. Accordingly, the meridional flow attains its largest velocities at the boundaries and decreases inside the convection zone. The thickness of the boundary layers, where meridional flow is concentrated, decreases with rotation rate, so that an advection-dominated regime of dynamos is not probable in rapidly rotating stars. Angular momentum transport by convection and by the meridional flow produce differential rotation. The convective fluxes of angular momentum point radially inward in the case of slow rotation but change their direction to equatorward and parallel to the rotation axis as the rotation rate increases. The differential rotation of main-sequence dwarfs is predicted to vary mildly with rotation rate but increase strongly with stellar surface temperature. The significance of differential rotation for dynamos has the opposite tendency to increase with spectral type.

A brief survey is given on the main characteristics of ‘bright points’ and of arch filaments in young bipolar spotgroups. Observations show that both features are closely associated, thus indicating that they have a common cause. It is suggested that the propagation of expanding and increasing active-region magnetic fields through the chromosphere might be that cause.

We summarize the characteristics of 85 spectroscopic orbits derived from more than two decades of radial-velocity monitoring of stars in the old open cluster M 67, with special emphasis on the blue stragglers and other members that do not fall on the evolutionary tracks expected for isolated single stars.

The God-father of psychoanalysis Professor Sigmund Freud taught us that the behaviour of adults depends on their early childhood experiences. in the same spirit, the problem of cosmological analysis is to derive the observed present day situation and structure of the Universe from certain plausible assumptions about its early behaviour. Perhaps the most important single statement about the large scale structure is that there is no structure at all on the largest scale − 1000 Mpc and more. On this scale the Universe is rather uniform, structureless and isotropically expanding - just according to the simplified pictures of Einstein-Friedmann……. Humason, Hubble…. Robertson, Walker. On the other hand there is a lot of structure on the scale of 100 or 50 Mpc and less. There are clusters and superclusters of galaxies.

As an introduction to the symposium the related problems of the distances, structures and chemical compositions of the Magellanic Clouds are reviewed.

Gaia is an ambitious space astrometry mission of ESA with a main objective to map the sky in astrometry and photometry down to a magnitude 20 by the end of the next decade. While the mission is built and operated by ESA and an industrial consortium, the data processing is entrusted to a consortium formed by the scientific community, which was formed in 2006 and formally selected by ESA one year later. The satellite will downlink around 100 TB of raw telemetry data over a mission duration of 5 years from which a very complex iterative processing will lead to the final science output: astrometry with a final accuracy of a few tens of microarcseconds, epoch photometry in wide and narrow bands, radial velocity and spectra for the stars brighter than 17 mag. We discuss the general principles and main difficulties of this very large data processing and present the organization of the European Consortium responsible for its design and implementation.

The main theories of solar rotation are critically reviewed.

The interaction of large-scale convection with rotation gives rise to a transport of angular momentum towards the equator and therefore to differential rotation with equatorial acceleration. (Large-scale convection is defined as follows: in a highly turbulent fluid, the small-scale turbulence acts as a viscosity and organizes fluid motions on a much larger scale.) This transport of angular momentum towards the equator arises because of the highly non-axisymmetric character of the large-scale convective motions in the presence of rotation. These motions tend to be concentrated near the equator. It is not surprising, therefore, that for magnitudes of large-scale convection which are needed to generate the observed solar differential rotation, large and unobserved pole-equator differences in flux appear in the Boussinesq approximation.

It is important, therefore, to take the variations in density into account. Studies of large-scale convection in a compressible rotating medium are still in a very early stage; these studies suggest, however, that the surface layers must indeed rotate differentially.

The interaction of rotation with convection appears to be especially efficient in generating a pole-equator difference in flux, Such a drives meridional motions, and the action of Coriolis forces on these motions gives rise to differential rotation. In the ‘large-viscosity’ approximation the problem separates; the meridional motions can be determined first (from the radial and latitudinal equations of motions, and the energy equation) and the angular velocity can be determined next from the azimuthal equation of motion. Since very little is known about compressible large-scale convection, it has been assumed in the development of this theory that the stabilizing effect of rotation on turbulent convection depends on the polar angle θ and on depth. The solution for the angular velocity in the large viscosity approximation gives a differential rotation that varies slowly with depth. As a consequence, the large viscosity approximation is not valid over most of the convection zone, the Coriolis term being larger than the viscous term; a thin layer at the top excepted. (It appears, however, that if the angular velocity, ω, is a slowly varying function of depth and the azimuthal stresses vanish at both ends of the convection zone, then the general behavior of ω will be very much like that predicted by the large viscosity approximation.)

The stabilizing effect of rotation on turbulent convection is neglected; if differential rotation is significant over the entire convection zone, and if the meridional and large-scale convective velocities are not too large, then in the radial and latitudinal equations of motion, the main balance of forces is between pressure gradients, buoyancy and Coriolis forces. If rotation is not constant along cylinders, then the differential rotation gives rise to latitudinal variations in the convective flux which are proportional to (where T is the temperature and g is gravity). In the lower part of the convection zone, is of the order of the superadiabatic gradient itself. Therefore large pole-equator differences in flux, will be present unless the angular velocity is constant along cylinders. The meridional velocities associated with this rotation law are not small, however, and could generate a significant It could well be that large s can be avoided only if rotation is uniform in the lower part of the convection zone. (To be certain of these results, however, it is important to estimate the magnitude of the stabilizing effect of rotation on turbulent convection.)

Turbulent convection is driven by the buoyancy force which thus introduces a preferred direction: gravity. In consequence, the turbulence in the sun should be anisotropic and if this is the case the convection zone cannot rotate uniformly. The degree of anisotropy is not known and must be determined from the observed solar differential rotation. The anisotropy is such that the horizontal exchange of momentum is larger than the vertical.

The normal mode of vibrations and the inner rotation of the Sun are briefly discussed.

A comprehensive overview of the $\lambda$ Bootis stars is presented. This small group (only a maximum of 2% of all objects in the relevant spectral domain) are Population I late B to early F-type stars, with moderate to extreme (up to a factor 100) surface underabundances of most Fe-peak elements and solar abundances of lighter elements (C, N, O, and S). They form a separate group among the classical chemically peculiar objects of the upper Main Sequence as their underabundances are quite outstanding. The basic membership criteria as well as the theories to explain the $\lambda$ Bootis phenomenon are covered. New observations including detailed elemental (surface) abundances, tests for pulsational instability, fluxes in the IR region, and measurements from the Hipparcos satellite permit one to make a statistical sound analysis of the group properties. Details of the evolutionary status, abundance pattern and tests for developed theories are presented.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Ion-neutral chemistry in Titan's upper atmosphere (~ 1000 km altitude) is an unexpectedly prodigious source of hydrocarbon-nitrile compounds. We report observations from the Cassini Ion Neutral Mass Spectrometer (INMS; Waite et al. 2004) and Cassini Plasma Spectrometer (CAPS; Young et al. 2004) that allow us to follow the formation of the organic material from the initial ionization and dissociation of nitrogen and methane driven by several free energy sources (extreme ultraviolet radiation and energetic ions and electrons) to the formation of negative ions with masses exceeding 10,000 amu.

We estimate near-surface flows using the techniques of f-mode time-distance helioseismology together with MDI/SOHO data. (1) Synoptic maps of horizontal flows are obtained for 1996, 1998 and 1999. Rotation, torsional oscillations and meridional circulation are measured. We detect weak large-scale flows converging toward active regions. Travel times are found to be shorter at locations of high magnetic activity. In addition, we measure the motion of the supergranulation pattern. (2) Realistic travel-time sensitivity kernels are used in an iterative deconvolution to infer horizontal flows at a high spatial resolution. The radial outflow outside a sunspot penumbra, called the moat, is measured.

Meteoroids observed to disintegrate in the terrestrial atmosphere can be directly linked to their parent bodies in case that they belong to certain meteor showers. We present a list of two dozens of parent bodies reliably associated with well recognized meteor showers. Among the parent bodies are long period comets, Halley-type comets, Jupiter family comets, comets of the inner solar system (such as 2P/Encke) and asteroids. Physical and chemical properties of meteoroids coming from various parents are compared on the basis of meteor heights, decelerations, light curves and spectra. Jupiter family comets produce meteoroids with the lowest strength, namely porous aggregates of dust grains with bulk densities of about 0.3 g cm−3 or less. Halley type material is somewhat stronger and the material related to comet Encke is even stronger. In addition, small strong constituents, perhaps similar to carbonaceous chondrites, can be encountered within the normal cometary material. The strength of cometary material is also enhanced by long-term exposure to cosmic rays and by solar heating in the vicinity to the Sun (r<0.2 AU). Both these processes lead to the loss of volatile sodium. Southern δ-Aquariids, Geminids and partly also Quadrantids were influenced by solar radiation. We argue that these showers, the asteroids associated with them ((3200) Phaethon and 2003 EH1), and the whole interplanetary complexes they belong to are of cometary origin. The argument is supported by lower than chondritic Fe/Mg ratio found in Geminids as well as in Halley type comets. The typical property of stony meteoroids of asteroidal origin is the presence of internal cracks which cause that the incoming meteoroids are much weaker than the recovered meteorites.

Comets account for a small but very significant fraction of impactors on the Earth. Although the total number of Earth-crossing comets is modest as compared with asteroids, the more eccentric and inclined orbits of the comets result in much higher encounter velocities with the planet. Additionally, some Earth-crossing comets are significantly larger than any current near-Earth asteroids (NEAs); comets 1P/Halley and C/1995 O1 Hale-Bopp are good examples of this. Thus, the most energetic impacts on the Earth likely result from comets and not NEAs. The mean impact probability for long-period comets is 2.4× 10−9 per comet per perihelion passage, assuming the perihelion distribution of Everhart (1967), with a most probable encounter velocity of 53.5 km sec−1. There are 21 known Earth-crossing Jupiter-family comets with a mean impact probability of 1.6× 10−9 per comet per year and a most probable encounter velocity of 17.0 km sec−1. For the 16 known Earth-crossing Halley-type comets the mean impact probability is 1.2× 10−10 per year with a most probable encounter velocity of 51.3 km sec−1. The poor knowledge of the size distribution of cometary nuclei makes it difficult to estimate actual impact energies at this time, though that situation is slowly improving, in particular for the Jupiter-family comets.

The Giant Metrewave Radio Telescope (GMRT) coming up near Pune, India will be one of the important instruments for pulsar research work at metre wavelengths. Here we describe the capabilities of the GMRT for pulsar work and give the current status of the telescope in this context. Results from recent test observations are also summarised.

We investigate the outcome of collisions of Ceres-sized planetesimals composed of a rocky core and a shell of water ice. These collisions are not only relevant for explaining the formation of planetary embryos in early planetary systems, but also provide insight into the formation of asteroid families and possible water transport via colliding small bodies. Earlier studies show characteristic collision velocities exceeding the bodies' mutual escape velocity which—along with the distribution of the impact angles—cover the collision outcome regimes ‘partial accretion’, ‘erosion’, and ‘hit-and-run’ leading to different expected fragmentation scenarios. Existing collision simulations use bodies composed of strengthless material; we study the distribution of fragments and their water contents considering the full elasto-plastic continuum mechanics equations also including brittle failure and fragmentation.

I review the observational side of the present state of the debate about the dark matter in galaxies, with emphasis on the core/cusp problem in low surface brightness galaxies, and the question of maximum/sub-maximum disks in spiral galaxies. Some remarks are made about the dwarf spheroidals around the Milky Way, and about elliptical galaxies.

We present a simple, physically-motivated model to interpret consistently the emission from galaxies at ultraviolet, optical and infrared wavelengths. We combine this model with a Bayesian method to obtain robust statistical constraints on key parameters describing the stellar content, star formation activity and dust content of galaxies. Our model is now publicly available via a user-friendly code package, MAGPHYS at www.iap.fr/magphys. We present an application of this model to interpret a sample of ~1400 local (z<0.5) galaxies from the H-ATLAS survey. We find that, for these galaxies, the diffuse interstellar medium, powered mainly by stars older than 10 Myr, accounts for about half the total infrared luminosity. We discuss the implications of this result to the use of star formation rate indicators based on total infrared luminosity.

Models of structure formation based on cold dark matter predict that most of the small dark matter haloes that first formed at high redshift would have merged into larger systems by the present epoch. Substructure in present-day haloes preserves the remains of these ancient systems, providing the only direct information we may ever have about the low-mass end of the power spectrum. We describe some recent attempts to model halo substructure down to very small masses, using a semi-analytic model of halo formation. We make a preliminary comparison between the model predictions, observations of substructure in lensed systems, and the properties of local satellite galaxies.

The central stars of planetary nebulae represent seemingly well-defined late stages of stellar evolution. Theoretical investigations with predictions of evolutionary tracks impose difficult requirements for observational data. Measurements of spectral energy distributions, of colors, and of magnitudes, and spectroscopic observations are all urgently needed.

A way of treatment of evolution of common envelope binaries based only on the laws of conservation of energy and angular momentum is suggested. It is shown that the final configuration depends on masses of components and initial period of the system, and on parameters describing friction in the envelope, and mass loss by the system. Possible final stages for massive binaries are either a Thorne-Zytkow type object for initially close binaries or a Wolf-Rayet star in pair with a relativistic compact remnant for wider ones. In the course of disruption of the latter system with orbital periods up to several hours very high space velocity (up to 500 km/s) pulsars can arise.