E-ELT: UK Project Pages

The current status of the E-ELT programme will be presented.

The UK has been taking leading roles in the development of the E-ELT instrument and adaptive optics programme since 2005 when we led the instrument studies in the EU Framework 6 ELT Design Study. This has culminated in the opportunity to lead one of the first light instruments. I will outline the work that enabled us to get in this position, and describe the options open to the UK as the instrument roadmap evolves. It is gratifying to see that UK is seen as a prefered partner for many of the instruments, but of course we cannot do everything. This meeting is part of the process towards deciding where future UK priorities should lie.

HARMONI is one of two instruments forming the E-ELT's first light suite. It provides the core spectroscopic capability at visible and near-infrared (0.47 to 2.45 μm) wavelengths, over a range of resolving powers from R (≡λ/Δλ) ~ 4000 to R~20000. The instrument is an integral-field spectrograph, obtaining simultaneous spectra of ~32000 spatial elements arranged in a contiguous field. HARMONI is conceived as a work-horse instrument, that will support a broad range of science programs. HARMONI will excel at ultra-sensitive, diffraction limited, spatially resolved, physical, chemical and kinematic studies of astrophysical sources. I will present an overview of the instrument's capabilities, and highlight several science cases where we expect HARMONI will make a big impact.

MICADO is the adaptive optics imaging camera for the E-ELT. It has been designed and optimised to work with the LGS-MCAO system MAORY, and will provide diffraction limited imaging over a wide (1arcmin) field of view. For initial operations, and perhaps also more permanently, it can also be used with its own simpler AO module that provides very high performance on-axis using natural guide stars. The instrument will also have a simple spectrograph with a large simultaneous wavelength coverage. I will describe the instrument's key capabilities and expected performance, and outline the instrument concept, pointing out the main changes since Phase A. I will finish by discussing a few of the science drivers, highlighting the astrometric capability.

The ‘Mid-infrared ELT Imager and Spectrograph’ (METIS) will be the third instrument on the European Extremely Large Telescope (E-ELT). METIS will provide diffraction limited imaging in the atmospheric L/M and N-band from 3 to 14 μm over an 18 ̋×18 ̋ field of view, as well as high contrast coronagraphy, medium-resolution (R ≤ 5000) long slit spectroscopy, and polarimetry. In addition, an integral field spectrograph will provide a spectral resolution of R ~ 100,000 at L/M band. The reduction of the E-ELT aperture size had little impact on the METIS science case. Focusing on highest angular resolution and high spectral resolution, METIS will deliver unique science, in particular in the areas of exo-planets, proto-planetary disks and high-redshift galaxies, which will be illustrated in this presentation.

HIRES will be a unique facility to measure atmosphere of transiting planet. It will be possible to probe their atmospheric composition without the need to resolve them directly. This can notably be done via transmission spectroscopy during a planetary transit. This method relies on the fact that the observed size of the planet will change depending on wavelength due to: the thermal structure of the atmosphere, the presence of clouds and the absorption and mixing of chemical species. These measurements will open the door to new insights and the potential to carry comparative exoplanetology.

High resolution spectroscopy has made a crucial contribution to the discovery and continued expansion of the field of exoplanets. This has manifest itself across a range of techniques and measurements at a variety of wavelengths. The E-ELT offers access to precise radial velocities derived at various optimum wavelengths for much fainter objects. Consideration will be given as to how nearby planetary companions can be discovered across the HR diagram in particular for low-mass brown dwarfs.

The strong surface gravity of white dwarfs implies that metals will sink out of the photosphere on time-scales that are orders of magnitude shorter than their cooling ages, and therefore white dwarfs are expected to have either pure hydrogen or helium atmospheres. Yet, the existence of metal-polluted white dwarfs has been a conundrum for nearly a century. We know now that these white dwarfs are polluted by accretion of rocky debris, remnants of a former planetary system. With hindsight, this is may not come as too much of a surprise, as our Sun will eventually evolve in a white dwarf orbited by Mars, the outer planets, and hosts of asteroids - and a similar fate awaits many of the known exo-planetary systems! State-of-the art model atmosphere analyses of high-resolution spectra of white dwarfs demonstrate that the bulk composition of the circumstellar debris is overall similar to that of the terrestrial planets in the Solar system, yet there is evidence for a variety of thermal processing and possibly differentiation in the parent bodies. Perhaps most astonishing are the lower limits on the mass of the parent bodies that were accreted, ranging up to 1e24g, i.e. well above the most massive asteroids in the Solar system. These chemical abundance analyses are currently, and for some time to come, by far the most precise studies of extra-solar planetary material, and are now being used by theorists to constrain the formation of terrestrial planets. A key limitation in this exciting new field of exo-planetary research is the faintness of white dwarfs: to date, only about a dozen "bright" (V~15) metal-polluted white dwarfs have been studied in sufficient detail, at the expense of substantial amounts of Keck Hires and VLT UVES/X-Shooter time. With the vast aperture of the E-ELT, and an efficient high-resolution spectrograph, it will be possible to carry out elaborate abundances studies for large numbers of white dwarfs, effectively determining the parameter space that allows the formation of terrestrial planets. Establishing the necessary target samples will be accomplished by a combination of the VST and VISTA public surveys and low-resolution follow-up with 4MOST. I will provide a brief overview of the current state of the field, and outline the requirements for future high-resolution instrumentation.

A key tool for understanding the difference in the physics of the formation of planets (i.e. objects which form in orbit around a star) as opposed to stars and brown dwarfs will be their respective mass functions. Whilst determinations of the mass functions for planets are making rapid progress, that for brown dwarfs at "planetary" masses is stalled by the faintness of the objects to be observed. Thus although the data from 4 and 8-m class telescopes clearly demonstrate that the number of stars as a function of mass "turns over" with a mean mass of about 0.5 Mo, we will need the next generation of telescopes to go to masses comparable to planets. These objects are brightest when young, and so this science case requires multi-object spectroscopy of star-forming regions.

Accurate chemical abundance information provides a powerful diagnostic of a galaxy's formation and star-forming history. However, obtaining such information is extremely challenging, and it has been shown recently that abundances derived from the spectra of HII regions are highly uncertain. Here I will present a new method of extracting a galaxy's chemical abundances from the spectra of their brightest stars, the Red Supergiants (RSGs). The main advantage of this technique over other stellar abundance methods is that it operates at low spectral resolution, and I will show that in the EELT era it will be able to map the abundances of entire galaxies in a single night out to impressive distances of 70Mpc. I will also show that this technique can extract metallicities from massive clusters of stars, objects which contain up to 100 RSGs, pushing the EELT's limiting distance out to an eye-watering 700Mpc.

One of the major ways in which new telescopes and instruments contribute to our understanding of galaxy formation and evolution is through surveys. The ELT will have the capability to perform surveys at an unprecedented depth both spectroscopically and through imaging. Current surveys with 8-10m telescopes are still scratching the surface of what could be done in terms of probing the distant galaxy population. The ELT will be fundamental in surveying the high-z universe to measure properties of some of the earliest galaxies, including luminosity and mass functions, kinematic relationships, as well as directly tracing processes of galaxy formation such as star formation and merging. This talk will go through this issues and how ELT can have a huge impact in this area by carefully planned programmes.

Observations of near-pristine gas at high redshifts are bringing us closer to unravelling the nature of the First Stars responsible for cosmic reionisation, complementing and extending parallel efforts towards the same goal based on studies of the oldest stars in the Milky Way. Both stellar and extragalactic strands have reached the photon-starved regime with current facilities and now await the advent of the 30-40 m class telescopes for the next major strides forward.

I will report on the workshop "Toward the Science Case for ELT-HIRES" held at 13&14 September in Cambridge.

Following on the science cases and the associated science requirements that were discussed at a recent workshop in Cambridge, I will discuss the specifications and an initial instrument concept that are being envisaged for the high resolution instrument (HIRES) for the E-ELT. A very wide, simultaneous spectral coverage, from the optical to the near-IR, including the K-band, is highly desired by most science cases. Besides the high spectral resolution mode (R=100,000-200,000), an intermediate resolution mode (R=10,000-20,000) is also widely requested and can be easily accommodated. The latter mode can also have moderate multiplexing capabilities (multiplex of a few up to 10), possibly by synergically exploiting the same positioners of the MOS instrument on the E-ELT. The high resolution mode can also accommodate a small IFU mode. I will illustrate an initial concept of a modular fiber-fed instrument that can accommodate these requirements.

Most of the spectrometers in the world are Fourier Transform Spectrometers (FTS) but only a few are used in astronomy where diffraction grating spectrometers (DGS) dominate. I will compare the pros and cons of FTSs and DGSs to see if there are any regimes in general where an FTS looks better than an DGS. In particular I'll consider the multi-object and high resolution requirements for the E-ELT.

The EAGLE instrument is a Multi-Object Adaptive Optics (MOAO) fed, multiple Integral Field Spectrograph (IFS), working in the Near Infra-Red (NIR), on the European Extremely Large Telescope (E-ELT). A phase A design study was delivered to the European Southern Observatory (ESO) leading to a successful review in October 2009. Since that time there have been a number of developments, which we summarize here. The science case for the instrument, while broad, highlighted in particular: understanding the stellar populations of galaxies in the nearby universe, the observation of the evolution of galaxies during the period of rapid stellar build-up between redshifts of 2-5, and the search for 'first light' in the universe at redshifts beyond 7. In the last 2 years substantial progress has been made in these areas, and we have updated our science case to show that EAGLE is still an essential facility for the E-ELT. This in turn allowed us to revisit the science requirements for the instrument, confirming most of the original decisions, but with some minor modifications. The original location considered for the instrument (a gravity invariant focal station) is no longer in the E-ELT Construction Proposal, and so we have performed some preliminary analyses to show that the instrument can be simply adapted to work at the E-ELT Nasmyth platform. Since the delivery of the Phase A documentation, MOAO has been demonstrated on-sky by the CANARY experiment at the William Herschel Telescope.

Astrophysics aims to understand the complexity of an almost incommensurable number of stars, stellar clusters and galaxies, including their formation and their current interactions with the interstellar and intergalactic media. Many fundamental discoveries in astronomy have required demographic studies of a representative number of sources. Were there only to be a single MOS at the E-ELT, the instrument would need to be versatile enough for addressing a significant part of the requirements in spatial, spectral resolution, wavelength coverage and multiplex. This will be illustrated through science cases ranging from the Local Universe to the most distant galaxies.

The EAGLE and EVE Phase A studies for instruments for the European Extremely Large Telescope (E-ELT) originated from related top-level scientific questions, but employed different (yet complementary) methods to deliver the required observations. We re-examine the motivations for a multi-object spectrograph (MOS) on the E-ELT and present a unified set of requirements for a versatile instrument. Such a MOS would exploit the excellent spatial resolution in the near-infrared envisaged for EAGLE, combined with aspects of the spectral coverage and large multiplex of EVE. We briefly discuss the top-level systems which could satisfy these requirements in a single instrument at one of the Nasmyth foci of the E-ELT.