We will review the metallicity of the CIV and OVI phases of the IGM in the redshift range $z\sim 0.1$-5 together with their contributions to the cosmic baryon density. The current studies are limited to regions with overdensities of 3-10; the heavy element enrichment in regions with gas densities close to the mean cosmic density will be probed with future ELTs. We will also investigate the possibilities of detecting metals at $z\sim 10$ and underline the requirements on ELTs due to the anticipated faintness of the early generations of galaxies, QSOs and transient objects.

The project of the Russian 6m BTA telescope reconstruction was cancelled in 2004 because of financial problems. In the beginning, it was planned to replace the existing 42 ton parabolic main mirror by a new one of 8m diameter using the Zerodur blank provided by the Germain company Schott.

Russia still possesses a high potential in the development of large-scale optics and mechanics. A new 25m telescope with the segmented mirror was the subject of wide speculations. Strange as it may seem, the country with the world largest territory has no good site for a large astronomical observatory. Any project of the national observatory is therefore faced with the necessity of looking for a foreign partner. We are also studying the possibility of joining one of the large international projects, including the ESO projects OWL, ALMA and others. At the same time, work on a few Russian space astronomical missions is going on well.

The detection of telluric extra-solar planets implies an extremely high contrast long exposure imaging capability at near-infrared and probably visible wavelengths. We present here the core of any Planet Finder instrument which is the extreme AO sub-system. The level of AO correction directly impacts on the exposure time required for planet detection. The extreme adaptive optics system has to correct for the perturbation induced by the atmospheric turbulence as well as for the internal aberrations of the instrument itself. An example of application is proposed in the frame of the EPICS project (XAO system for the ESO OWL telescope).

We describe how the Virtual Observatory (VO) projects in Europe, the USA, Japan, and elsewhere are meeting the challenge of providing simple and efficient access to the data from the world's observational facilities, together with applications and computational resources required to support the analysis of this data. We note the pan-European Euro-VO project and its technological development VO-TECH project which are now in the process of designing the framework for comprehensive access to emerging high data volume facilities such as ESO's VISTA infrared survey telescope.

Science drivers from major new astronomical missions are helping to define the development of the VO. Scientifically this is in terms of developing systems able to meet the demands of the main science programmes shaping the ELTs. VOs must be able to handle the large data streams from the complex multiplexed instruments on the ELTs, and provide access to applications required to analyse/interpret the data. VOs must enable the effective distribution of ELT data to the global community.

Conversely, the rapid development of the Virtual Observatory, offers opportunities for major new projects such at the ELTs. This could be: in the design of their down stream data-flow systems; in terms of opening up access to ‘real-time’ availability of ancillary data flows; in multi-wavelength observational programmes.

We highlight these areas, and give some specific current examples of early VO usage in delivering science from, e.g. the mining of deep multi-wavelength surveys to study the high redshift universe.

For a European ELT, we discuss science requirements and technical options. Science includes from the solar system to the first stars and galaxies. ELT and instrument needs are commented. Design options are discussed for the primary mirror, its segmentation and shape, and an adaptive secondary mirror. Adaptive optics and enclosure are commented.

The capability of extremely large telescopes (ELTs) to resolve stellar populations in distant galaxies has been investigated through simulation. With real stellar clusters as templates, images were created using a realistic point spread function model. Through variation of parameters such as aperture, Strehl ratio and exposure, as well as use of various stellar populations and densities, we study ELT capability to probe galaxy formation and evolution history. We conclude that a 50m ELT should allow study of these processes in the Virgo galaxy cluster.

The amount and spatial distribution of dark matter in elliptical galaxies are poorly known, despite extensive observations with multi-object spectrographs on 4-10m-class telescopes. We examine the prospects for measuring the structure of dark matter halos in elliptical galaxies — and the orbital properties of their planetary nebula and globular cluster systems — from radial velocity measurements made with WFOS, a wide-field optical spectrograph operating on the Thirty Meter Telescope (TMT).

Supernova remnants are the remains of the outer envelope of the supernova progenitor star. Neutron stars are one of the possible remnants of the region where the explosion detonated. Our knowledge, from galactic studies, of SNRs is well established as their morphology can be understood in terms of the initial blast and out-gassing during the last stages of the progenitor. However, observationally the link between neutron stars and SNRs is only poorly established. During a supernova there are a number of possibilities to produce a condensed remnant - no remnant; a neutron star (pulsar?); a magnetar; a black hole or something more exotic. We do not know what fraction of supernovae go down these possible paths. In the ELT era we will have the first real opportunity to sample the pulsar population in external galaxies and get a more comprehensive survey of optical emission from local pulsars. Such a survey would have significantly reduced biases compared to the current state of radio surveys particularly in the area of pulsar-SNR statistics. Furthermore, a 50m telescope will be able to survey galaxies out to at least 20 Mpc for young SNRs using H$\alpha$:[OIII] and H$\alpha$:[SII] ratios. Currently there are over 1500 radio pulsars detected, 14 of which have been observed at optical wavelengths. Although small in number the family of optical pulsars yield much useful information in bridging the gap between the long wavelength radio emission and the high energy gamma-ray emission from pulsars. Specifically optical techniques are currently the only way of detecting polarisation in the high-energy regime. The advent of ELTs will increase the detection rate of local galactic pulsars and provides the possibility of detecting a significant number of extragalactic optical pulsars. Phenomenologically, the Pacini scaling law predicts $\sim$150 galactic pulsars to have pulsed optical emission with an m$_{V} <$32. Using SKA, Crab-like giant radio pulses should be detectable out to 7 Mpc. In contrast Crab-like pulsars would have a normal peak pulsed m$_{V}\,\sim$31 at 10 Mpc making ELT optical observations more sensitive than radio observations and the best method for extragalactic pulsar discovery. To date only five AXPs have observed IR emission and two optical emission. ELTs will be able to sample the AXP population within the Galaxy as well as the local group again providing better statistics for the birth rate of AXPs compared to ‘normal’ pulsars. A combination of an AXP and ‘normal’ pulsar survey will make a significant contribution to the birthrate question - what fraction of supernovae produce pulsars compared to AXPs and other condensed objects?

We review the current status of searches for high redshift galaxies and quasars, together with their derived luminosity function, star formation history and relative contribution to the UV ionizing background. These searches have been carried out in the optical and near-infrared with the HST for very deep pencil beam surveys and ground-based telescopes for deep large area surveys. The peak of galaxy and black hole formation activity occurs at $z\sim 2$-3, with a strong decrease in UV luminosity density in the redshift interval $z\sim 3$ to 6. This decrease seems to extend beyond $z\sim 6$ for luminous galaxies, as there are only a few $z\sim 7$-8 secure galaxy candidates. The star formation rate at $z\sim 6$ is dominated by 0.1 L$^{\star}$ galaxies. The $z \gtrsim 5$ samples for both types of sources are too small to constrain the faint end of their luminosity function or even its knee. Consequently, predictions of the number density of $z \gtrsim 7$ galaxies is highly uncertain; their search with JWST and ELTs should cover areas of at least $\sim$1 deg$^2$ and will require long campaigns (${\gtrsim} 1$ month). Faint quasars of small black hole mass should also be detected in these surveys. Searches for $z\sim10$ rare, bright quasars and higher $z$ transient sources, gamma-ray bursts and population III SNe, should be undertaken with dedicated facilities. The physical properties of high $z$ galaxies and the metal-enrichment of the intergalactic medium at early epochs will be determined by high-resolution spectroscopic observations with ELTs requiring substantial exposure times (${\sim} 100$ hr).

Verification of theoretical predictions of an oscillating behavior of the fine-structure constant, $\alpha$, with cosmic time requires high precision measurements at individual redshifts, while in earlier studies the mean $\Delta\alpha/\alpha$ values averaged over wide redshift intervals were usually reported. This requirement can be met via the Single Ion Differential $\alpha$ Measurement (SIDAM) procedure. We apply SIDAM to the FeII lines associated with the damped Ly$\alpha$ system observed at $z = 1.15$ in the spectrum of HE0515–4414. The weighted mean calculated on the base of carefully selected 34 FeII pairs is $\langle \Delta\alpha/\alpha \rangle = (-0.07\,{\pm}\,0.84)\times10^{-6}$. The precision of this estimate represents a large improvement over previous measurements of $\Delta\alpha/\alpha$.

A brief description of the QuantEYE instrument proposed as a focal plane instrument for OWL is given. This instrument is dedicated to the very high speed observation of many active phenomena with a photon counting capability of up to 1GHz. The system samples the beam in 10$\times$10 subpupils, each focused on a fast photon counting detector.

A software for simulations of observations with an Integral Field Spectrograph attached to an extreme adaptive optics system is presented here. This code, written in IDL, has been conceived within the CHEOPS project, a second generation “Planet Finder” instrument for ESO's VLT, and it has been successfully extended to the case of various ELTs in order to test the capabilities in detecting planets of an instrument based on Integral Field Spectroscopy (IFS). We present here, beside a general description of the procedure adopted to simulate IFS observations, a set of significant simulations of detections using OWL for different kinds of planets, in order to understand which objects are the best targets for an IFS-Planet Finder mounted on a 100m-class telescope.

Cool, extrasolar gas giants similar to Jupiter and Saturn in our own Solar System should be detectable by virtue of the light they reflect in the optical and near-infrared with the next generation of Extremely Large Telescopes (ELTs) equipped with adaptive optics systems. Broad band imaging or very low-resolution spectra should then enable the characterization of the orbit, mass, atmospheric scattering properties, and presence of large rings in these gas giant analogues.

A highlight science case for the European ELT is: First light - The First Galaxies and the Ionization State of the Early Universe. It aims at understanding the formation and evolution of the first sources of light at the end of the Dark Ages and of the re-ionization of the Universe. The corresponding instrument requirements are: a few tens of integral field units with spatial sampling $\sim$20mas and individual fields of ${\sim}1''$ over a wide field of view of $5' \times 5'$ or larger. Multi-Object Adaptive Optics is required to locally provide significant image quality enhancement. Spectroscopic observations are required in the near IR domain with a spectral resolution of a few 1000. MOMFIS is a preliminary instrument concept designed for OWL around this science case. The instrument concept and preliminary design are presented. Development efforts are estimated, as well as development risks and required R&D activities.

Late-type giants (i.e., stars on the red and asymptotic giant branches, RGB/AGB, respectively) are dominant contributors to the overall spectral appearance of intermediate age and old stellar populations, especially in the red/near-infrared part of the spectrum. Being intrinsically bright, they are well suited for probing distant/obscured populations, especially those that can not be studied with their fainter members, like main sequence turn-off stars or subgiants. Late-type giants and supergiants will be the only stellar types accessible in intermediate age and old populations beyond the distances of several Mpc with the future 30-50 m class extremely large telescopes (Olsen et al. 2003). Indeed, proper understanding of their observable properties by means of theoretical models is of key importance for studying the evolution of stellar populations and their host galaxies.

Recent spectroscopic observation of $z=6.3$ GRB 050904 is reported with an emphasis on the importance of making similar prompt spectroscopy for long burst GRB events yet to come. A preliminary result of a survey for $z\sim7.0$ Lyman $\alpha$ emitters (LAEs) using a narrow band filter NBF973 is also presented.

Dwarfs of the spectral types late-M, L and T span mass regimes from very-low-mass stars through brown dwarfs down to young planetary objects. They all show massive molecular line-blanketing and the condensation of refractory species with decreasing $T_{\mathrm{eff}}$, leading to changes in chemical equilibrium composition and absorption due to dust grains. The spectral evolution from late-M through L to mid- and late-T classes is now understood as chiefly due to increasing amounts of condensates in the visible photosphere up to mid-L types, and the settling of dust clouds into deeper regions at the transition from L to T, resulting in a depletion of condensable elements in the upper atmosphere. The ensuing photospheric cooling also drives a change in carbon chemistry leading to the hallmark methane absorption features of T dwarfs.

Recent observations of brown dwarfs in the L-T spectral sequence and model atmosphere calculations have shown that these changes in spectral features reveal differences in the efficiency of cloud removal that seem to be triggered by an additional parameter besides effective temperature. We present models describing the settling of particle clouds as an equilibrium process between condensation, gravitational sedimentation and convective and turbulent mixing, based on 3D-hydrodynamical simulations for the description of the velocity field. These calculations predict a strong dependence of the settling on gravity, and can therefore explain observed differences between the spectral energy distributions of brown dwarfs of equal luminosity as an effect of different mass. Based on these calculations we would expect even stronger deviations in the colours of young brown dwarfs of very low mass from those commonly observed in the field. Such predictions seem to be in aggreement with the first observations of candidate planetary-mass objects, and would imply that extrasolar planets at very young ages have spectral energy distributions significantly different from previous models. Our models also predict characteristic time scales for the cloud formation processes that may be compared to observed variability in brown dwarfs.

I summarise the ELT requirements derived from the science cases in the area of galaxy formation/evolution and cosmology. This summary is based on the talks, posters and discussion in parallel Session A of this meeting, but also makes use of various publically-available ELT science case documents. Topics covered include studies of black holes, dark matter, properties of galaxies at a range of redshifts (including the first galaxies to form), fundamental constants and cosmology.

Both optical CCD detectors and infrared detector arrays have steadily evolved over the past 5 years, and have reached very satisfactory levels of quantum efficiency and dark current. Optical CMOS detector arrays have rapidly improved and are beginning to compete with CCD detectors. A new development of great relevance for future instrumentation is the integration of the readout electronics into an integrated circuit in close proximity to the detector, or, in the future, its vertical integration with the detector array and multiplexer. This paper reviews the present status of these technologies and identifies opportunities and risks for the next decade.

A key science driver for future ELTs is to chronicle the complete formation and evolutionary histories of a meaningful number of nearby galaxies through their resolved stars. The goal will be to measure the entire star formation and chemical enrichment histories of a sample of galaxies that includes all Hubble types and covers all of their components, demanding photometry of stars in regions with high surface brightness at distances of up to 20Mpc. We present simulations that compare the abilities of 20, 30, 50, and 100m telescopes to recover the correct stellar population mix represented in field star color-magnitude diagrams observed with $J$, $H$, and $K$ filters. As input, our simulations use scenes containing stars drawn from a mix of model isochrones with differing ages and metallicities, with surface densities set to match that found in the M31 bulge and at the effective radius of NGC 3379. We convolve these scenes with PSFs corresponding to the projected performance of MCAO systems containing two deformable mirrors, including the effect of realistic variations in the atmospheric turbulence profile over the span of the observations. These simulations provide a way to evaluate the scientific advances enabled by ELTs of differing apertures in the area of extragalactic stellar populations.