Extremely Large Telescope

Abstract:

The molecular gas content of local early-type galaxies is constrained and discussed in relation to their evolution. First, as part of the ATLAS 3D survey, we present the first complete, large (260 objects), volume-limited single-dish survey of CO in normal local early-type galaxies. We find a surprisingly high detection rate of 22%, independent of luminosity and at best weakly dependent on environment. Second, the extent of the molecular gas is constrained with CO synthesis imaging, and a variety of morphologies is revealed. The kinematics of the molecular gas and stars are often misaligned, implying an external gas origin in over a third of the systems, although this behaviour is drastically diffferent between field and cluster environments. Third, many objects appear to be in the process of forming regular kpc-size decoupled disks, and a star formation sequence can be sketched by piecing together multi-wavelength information on the molecular gas, current star formation, and young stars. Last, early-type galaxies do not seem to systematically obey all our usual prejudices regarding star formation, following the standard Schmidt-Kennicutt law but not the far infrared-radio correlation. This may suggest a greater diversity in star formation processes than observed in disk galaxies. Using multiple molecular tracers, we are thus starting to probe the physical conditions of the cold gas in early-types. © Copyright International Astronomical Union 2011.

Abstract:

We present the results of a design study for an integral field spectrograph as the "back-end" instrument for spectroscopy of exoplanets carried out in the context of the EPICS Phase A study. EPICS is the planet finder imager and spectrograph for the E-ELT. In our study we investigated the feasibility of an image slicer based integral field spectrograph and developed an optical design for the image slicer and the necessary pre-optics, as well as the spectrograph optics. We present a detailed analysis of the optical performance of the design. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Abstract:

VISTA was designed as a survey facility, and was optimized for use with the 64Mpix VISTA IR Camera in the sense that the optical system of the instrument and telescope was designed as a single entity. The commissioning of the IR camera therefore formed a major part of the system integration and commissioning of the whole VISTA system. We describe some aspects of the commissioning process for VISTA, the interplay between the camera and telescope systems, and summarize the results of the verification phase. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Abstract:

HARMONI is a proposed visible and near-infrared integral field spectrograph for the European Extremely Large Telescope. We are exploring the merits of adding a coronagraphic capability to HARMONI, specifically targeted at enabling observations of faint, nearby companions (primarily extra-solar planets) that require high contrast. Although HARMONI is not fed by extreme adaptive optics, we show that substantial contrasts can be achieved by post-processing of the hyperspectral data cube using spectral deconvolution. We make predictions of achievable contrast as a function of coronagraph design, based on realistic models of the telescope's aberrations. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Abstract:

Wide-field multi-object spectroscopy is a high priority for European astronomy over the next decade. Most 8-10m telescopes have a small field of view, making 4-m class telescopes a particularly attractive option for wide-field instruments. We present a science case and design drivers for a wide-field multi-object spectrograph (MOS) with integral field units for the 4.2-m William Herschel Telescope (WHT) on La Palma. The instrument intends to take advantage of a future prime-focus corrector and atmospheric-dispersion corrector (Agocs et al, this conf.) that will deliver a field of view 2 deg in diameter, with good throughput from 370 to 1,000 nm. The science programs cluster into three groups needing three different resolving powers R: (1) high-precision radial-velocities for Gaia-related Milky Way dynamics, cosmological redshift surveys, and galaxy evolution studies (R = 5,000), (2) galaxy disk velocity dispersions (R = 10,000) and (3) high-precision stellar element abundances for Milky Way archaeology (R = 20,000). The multiplex requirements of the different science cases range from a few hundred to a few thousand, and a range of fibre-positioner technologies are considered. Several options for the spectrograph are discussed, building in part on published design studies for E-ELT spectrographs. Indeed, a WHT MOS will not only efficiently deliver data for exploitation of important imaging surveys planned for the coming decade, but will also serve as a test-bed to optimize the design of MOS instruments for the future E-ELT. © 2010 Copyright SPIE - The International Society for Optical Engineering.