The conventional picture of disk accretion onto magnetized neutron stars has been challenged by the spin changes observed in a few X-ray pulsars, and by theoretical results from numerical simulations of disk-magnetized star interactions. Here we present a model for the torque exerted by accretion disks on magnetized neutron stars, assuming accretion continues even for fast rotators.

The scientific capabilities of the James Webb Space Telescope (JWST) fall into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. To enable these four science themes, JWST will be a large (6.5m) cold (50K) telescope launched to the second Earth-Sun Lagrange point early in the next decade. It is the successor to the Hubble Space Telescope, and is a partnership of NASA, ESA and CSA. JWST will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 27 microns. The scientific investigations described here define the measurement capabilities of the telescope, but they do not imply that those particular observations will be made. JWST is a facility-class mission, so most of the observing time will be allocated to investigators from the international astronomical community through competitively-selected proposals.

We discuss the results obtained so far in our ongoing search for the $^6$Li isotope in very metal-poor halo stars through very high resolution and S/N spectroscopy with the Subaru High Dispersion Spectrograph, and the consequent implications. Besides definitively confirming the existence of $^6$Li in the star HD 84937, we achieve a tentative detection in the extremely metal-poor star G 64-12 ([Fe/H]$\,{\simeq}\,{-}$3.2). For two other stars with [Fe/H] ${\sim}\,{-}3$, only upper limits were derived. Together with the VLT/UVES results of Asplund et al., this indicates unexpectedly high $^6$Li abundances in at least some stars at very low [Fe/H]. The findings are discussed in light of different production scenarios, including the structure formation cosmic ray model and other possibilities.

We studied a sample of 38 intermediate redshift MgII absorption-selected galaxies using (1) Keck/HIRES and VLT/UVES quasar spectra to measure the halo gas kinematics from MgII absorption profiles and (2) HST/WFPC–2 images to study the absorbing galaxy morphologies. We have searched for correlations between quantified gas absorption properties, and host galaxy impact parameters, inclinations, position angles, and quantified morphological parameters. We report a $3.2\sigma$ correlation between asymmetric perturbations in the host galaxy morphology and the MgII absorption equivalent width. We suggest that this correlation may indicate a connection between past merging and/or interaction events in MgII absorption-selected galaxies and the velocity dispersion and quantity of gas surrounding these galaxies.

The detection of interstellar molecules relies on the precise knowledge of spectral line positions from laboratory measurements. Technical developments of recent years have led to an extension of the accessible spectral range towards shorter wavelengths. New telescopes like SOFIA, the HIFI instrument aboard the Herschel satellite, and ALMA will be used for astrophysical observations in the terahertz region. The Cologne group has developed precise spectrometers to study molecules of astrophysical importance under laboratory conditions and to obtain characteristic spectra for their possible detection in space. We present recent results on light hydrides, carbon-chain molecules and more complex species.

Detailed studies of dwarf galaxies in the Local Group have revealed an amazing diversity in their star formation histories. Young and intermediate-age stellar populations are observed in some gas-poor dwarf ellipticals, like Fornax and Carina, where naively one would have expected to find preferentially old stellar populations. There are evidences that the environment might drive the evolution of these galaxies.

In order to explore stellar populations in dwarf galaxies in an environment denser than that of the Local Group we have observed 14 dwarf elliptical galaxies in Centaurus group in near-IR $J_s$ and $K_s$ bands. The intrinsic properties of these galaxies, the metallicities and ages of their stellar populations and the presence or absence of bright, intermediate-age AGB stars will be correlated with extrinsic properties like the local galaxy density. Here we summarize our observations, present the sample and show near-IR color-magnitude diagrams and luminosity functions for ESO269-066 and AM1343-452 dwarf galaxies.

We present numerical investigations into the formation of massive stars from turbulent cores of density gradient $\rho \propto r^{-1.5}$. The results of five hydrodynamical simulations are described, following the collapse of the core, fragmentation and the formation of small clusters of protostars. We generate two different initial turbulent velocity fields corresponding to power-law spectra $P \propto k^{-4}$ and $P \propto k^{-3.5}$, and apply two different initial core radii. Calculations are included for both completely isothermal collapse, and a non-isothermal equation of state above a critical density ($10^{-14}$gcm$^{-3}$). Our calculations reveal the preference of fragmentation over monolithic star formation in turbulent cores. Fragmentation was prevalent in all the isothermal cases. Although disc fragmentation was largely suppressed in the non-isothermal runs due to the small dynamic range between the initial density and the critical density, our results show that some fragmentation still persisted. This is inconsistent with previous suggestions that turbulent cores result in the formation of a single massive star. We conclude that turbulence cannot be measured as an isotropic pressure term.

Discriminating exo-planetary photons from stellar photons with a ground-based instrument is a physically interesting and challenging issue. We propose an observational technique based upon both spectral and polarimetric coding to discriminate the exo-planetary photons. We also discuss a preliminary observation run performed with the spectrograph “CARELEC” on the 193 cm telescope at the Observatoire de Haute provence (OHP).

There are three types of energy sources that affect comet nuclei and may render them active: thermal – solar radiation, nuclear – radioactive decay, and gravitational – through collisions and tidal forces. These sources give rise to processes that, in turn, may release, absorb or transport energy: sublimation or recondensation of volatiles, crystallization of amorphous ice, heat diffusion and advection, gas flow through the porous nucleus. Each of these sources and processes has its own characteristic time scale (or rate) and these may differ by many orders of magnitude. It is the competition between various processes and the interaction between them – as one triggers the other, or else impedes it – that determine the activity pattern and the internal structure of a comet nucleus. Examples of such interactions and their outcome are presented, such as apparently sporadic activity at large heliocentric distances, obtained from numerical simulations of the behavior and evolution of comet nuclei. Confrontation of modeling results with observations provides feedback and constraints for the assumptions and parameters on which models are based. Adjusting the latter to match observations reveals properties of the nucleus that are otherwise inaccessible (except for in situ measurements by space missions). However, the interpretation of observations, such as production rates in relation to nucleus abundances, may be misleading. It is shown that monitoring production rates over the active part of a periodic comet's orbit may lead to conclusions regarding the composition and structure of the nucleus.

A Division 1 Working Group on “Nomenclature for Fundamental Astronomy” (NFA) was formed at the 25th IAU GA in 2003 in order to provide proposals for the new nomenclature associated with the implementation of the IAU 2000 resolutions on reference systems. This WG is also intended to make related educational efforts for addressing the issue to the large community of scientists. The activities of the NFA WG since October 2003 have consisted of newsletters, questionnaires, detailed e-mail discussion, and the preparation of WG recommendations and guidelines which are supported by explanatory documents. The NFA documents have been discussed during international meetings in 2004 and 2005. A NFA WG resolution proposal will be submitted to the IAU 2006 GA as a supplement to the IAU 2000 resolutions. The NFA material has been made available on the NFA web Bite at: http://syrte.obspm.fr/iauWGnfa/.

We discuss the evolution of the habitable zone around low mass and intermediate mass stars as they evolve off the main sequence. This work shows that this new class of stars should be included in the search for life because if planets could be found in their habitable zones, and these planets showed evidence for life, it is possible to empirically determine a lower limit to the timescale for the formation of life. This time scale is not well determined from the study of the Earth (or planets around main sequence stars), as life formation initially occurred during a period of heavy bombardment from comets and asteroids during the formation of the solar system. Our initial research was recently published (Lopez, Schneider, & Danchi 2005). We will describe our work in progress, in which we perform calculations and simulations aiming to demonstrate the potential of TPF and Darwin for the search and characterization of planets around evolved stars.

We report on astrophysical aspects of fully innovative very wide–field X-ray telescopes with high sensitivity. They are expected to contribute essentially to study of various astrophysical objects such as AGN, SNe, Gamma-ray bursts (GRBs), X-ray flashes (XRFs), galactic binary sources, stars, CVs, X-ray novae, various transient sources, etc.

Recent observations in visible photometry have provided B, V, R and I high quality colors for more than 130 objects. Color diversity is now a reality in the TNOs population. Relevant statistical analyses have been performed and all possible correlations between optical colors and orbital parameters have been analyzed. A taxonomy scheme based on multivariate statistical analysis of a subsample of 51 objects described by the 4 color indices (B-V, V-R, V-I and V-J) has been obtained. A tentative interpretation of the obtained groups in terms of surface characteristics is given. Moreover, an extension of this taxonomy to the other 84 objects for which only three colors indices (B-V, V-R, and V-I) are available, is also presented.

The faintness of these objects limits the spectroscopic observations. Despite this, our group provided visible and infrared spectra for 18 objects using the Very Large Telescope (ESO, Paranal, Chile). The wavelength region ranging 0.4–2.3 microns encompasses diagnostic spectral features to investigate organic compounds, minerals and ices present on the surface of the TNOs. The investigation of the surface variation can be an identifier of possible composition diversity and/or different evolution with different physical processes affecting the surface.

The current knowledge of the surface properties and composition of the population will be presented, analyzed and interpreted.

Using a large sample of MgII absorbers with $0.4<z<2.2$ detected by Nestor et al. (2005) in the Early Data Release of the SDSS, we present new constraints on the physical properties of these systems based on two statistical analyses: (i) by computing the ratio between the composite spectra of quasars with and without absorbers, we measure the reddening effects induced by these intervening systems; and (ii) by stacking SDSS images centred on quasars with strong MgII absorption lines and isolating the excess light around the PSF, we measure the mean luminosity and colours of the absorbing galaxies. This statistical approach does not require any spectroscopic follow up and allows us to constrain the photometric properties of absorber systems.

Massive stars are known to be formed in clusters. To understand their birth process it is essential to know the physical conditions of the parental cloud which is thought to play a critical role in determining the formation mechanism. In this contribution I summarize recent results from observations of dust, molecular and ionized gas emission we have made toward several massive star forming regions in the southern hemisphere. These observations are providing key evidence concerning the initial conditions for the formation of cluster of massive stars, allowing to characterize the physical properties of massive and dense cores and permitting to identify them in different stages of their early evolution.

The definition of UTC was implemented in 1972, principally to accommodate celestial navigation and follows recommendation 460 of the International Radio Consultative Committee (CCIR) in 1970. Since 1972 the use of electronic means to navigate has overtaken celestial navigation. This fact along with increasing public dissatisfaction with the possible disruption to modern electronic communications and navigation systems caused by the insertion of a leap second has called into question the current definition of UTC. An extensive review of the background and issues relating to the leap second can be found in Nelson, et al (2001).

We have entered a new era in the observational study of the kinematics of dwarf spheroidal and dwarf elliptical galaxies. Large telescopes with multi-object spectrographs can now obtain radial velocities of hundreds if not thousands of individual stars in the nearer dSph systems, while new sensitive longslit spectrometers can measure the kinematics of dE galaxies from their integrated light to unprecedented faint surface brightness levels. I review where we have been, where we are, and where we are going in the kinematic studies of these dwarfs systems.

A description of the Herschel Space Observatory and the Atacama Large Millimeter Array is presented. Their scientific potential and possible synergistic effects with ELTs is discussed. Herschel is a space-based far-infrared and submillimeter telescope to be launched in 2008 and will offer 3 years of routine science operations. ALMA will become fully operational around 2012 and will co-exist with ELTs. The synergy of being able to observe the same objects with similar angular resolution and sensitivity at long and short wavelengths will contribute to our understanding of astrophysical objects and processes in general.

Over the last few years, we have applied the CRESU (Reaction Kinetics in Uniform Supersonic Flow) technique to the study of neutral-neutral reactions and energy transfer processes in the gas phase. This has enabled the rates of a wide range of reactions between electrically neutral species to be measured down to temperatures as low as $\sim $10 K. These results have generated significant interest amongst theoretical chemists, and especially amongst astrochemists. Our measurements of low-temperature rate coefficients have had a significant impact on the models used to simulate the chemistry of dense interstellar clouds. In this article the motivations for the experimental study of reaction kinetics at low temperatures are described, and a detailed description of the CRESU technique is given, followed by a brief overview of the results obtained in Rennes and Birmingham. Four recent low-temperature kinetic studies are then described: the reaction O + OH and the interstellar oxygen problem, reactions of the C$_2$ radical, energy transfer in collisions of C($^3{\rm P}_J$) with He and H$_2$, and preliminary results on the reaction kinetics of the C$_4$H radical.

Very recent observations of the $^6$Li isotope in halo stars reveal a $^6$Li plateau about 1000 times above the predicted BBN abundance. We calculate the evolution of $^6$Li versus redshift generated from an initial burst of cosmological cosmic rays (CCRs) up to the formation of the Galaxy. We show that a pregalactic production of the $^6$Li isotope can account for the $^6$Li plateau observed in metal poor halo stars without additional over-production of $^7$Li. The derived properties of the CCRs could then be used to put constraints on the physics and history of the objects, such as Pop III stars, possibly responsible for these early cosmic rays. Consequently, we consider the evolution of $^6$Li in the Galaxy. Since $^6$Li is also produced by Galactic cosmic ray nucleosynthesis, we argue that $^6$Li can be depleted in halo stars with metallicities between [Fe/H]=−2 and −1.