Toby Moore Liverpool JMU RAS, London, May 2008

Infrared wavebands RegionWavelengthTemperatureTypical Objects Near-infrared1 – 5 μm580 – 2900 Kred giant stars, galaxies, YSOs Thermal near-IR2.5 – 5 μm580 – 1160 K Mid-infrared5 – 40 μm Kplanets, PP disks, warm dust Far-infrared40 – 350 μm8 – 70 Kemission from cold dust AstroNet Science Case recommendation for mid-IR astronomy: “Near- and mid-infrared imaging and spectroscopy at high spatial resolution and sensitivity provided by an Extremely Large Telescope with high performance adaptive optics will be essential…” (page 138)

The Mid-Infrared Toolbox Spectroscopy: Atomic fine-structure lines Atomic hydrogen lines Molecular hydrogen lines Polycyclic aromatic hydrocarbon (PAH) emission features Silicate emission/absorption features (crystalline and amorphous) Ices: H 2 O, CO, CH 4, CH 3 OH, NH 3 Gaseous molecules: CO, H 2 O, CH 4, C 2 H 2, HCN, OH, SiO 2, H 3 + e.g. isotope ratios D/H, gas content of circumstellar discs, etc. Imaging: Low susceptibility to dust extinction Continuum emission from dust (and very small grains) e.g. young circumstellar discs: reduced contrast of star/disk ratio Polarimetry: Asymmetric dust grains  short axis and L are aligned with B-field  dichroic effect  radiation passing through a medium  partially polarized Absorption: position angle ║ B-field; emission: ┴ B-field

METIS Science Case Proto-Planetary Disks Physical structure of the gas vs. dust disc: evidence for young planets; timescale and mechanism for gas dissipation (photo-evaporation, disc winds, planets, …); chemical content of the inner disc as a function of radius (water, organic molecules, …) Properties of Exoplanets Solar System Primordial material in cometary nuclei. 3-5μm spectrocopy The Growth of Super-massive Black Holes QSO activity at high z; evolution of nuclear starburst activity The Formation of Massive Stars & the stellar IMF The Galactic Centre Formation of Massive Ellipticals: Morphologies of the hosts of Sub- mm Galaxies GRBs at high redshifts

METIS Instrument Modes (TBC) Derived from science case and subject of Phase-A study BASELINE: L M N band diffraction limited high contrast imager (20"×20") L M N-band high-resolution (R ~ 100,000) IFU spectrometer (1"×1") Coronagraph Low resolution (R ≥ 100) spectroscopy (included in imager) OPTIONAL (subject to phase A study): Larger field of view Medium resolution spectroscopy (IFU or long slit) Q band (imaging and spectroscopy) Linear polarimetry (imaging and R ≥ 200 spectroscopy)

Space and Ground are Complementary Can the E-ELT compete with JWST-MIRI? Continuous spectral coverage Larger FOV with constant PSF Better imaging sensitivity Much better LSB sensitivity Better spectro-photometric stability 100% sky coverage, good weather Comparable PS spectral sensitivity 5-8 times higher angular resolution High spectral resolution (kinematics) Shorter response times Optional polarimetry Follow up as for HST →VLT

Anticipated Timeline (TBC) Sep 05 – Jul 06MIDIR Small Study (EU) Oct 07start preparations for phase-A Mar 08submission of phase-A proposal May 08 – Oct 09phase-A study 2010 – 2012phase-B 2013 – 2017phase C/D 2017first light

Phase-A Work Distribution

Adaptive Optics for the mid-IR wavefront sensing at 589nm  correction at 12μm? effect of water vapour fluctuations?  internal (low order) mid-IR wavefront sensor?  interaction with E-ELT AO system? The need for AO......and expected performance

Nodding and Chopping The E-ELT will not provide classical chopping The nodding performance is still unclear Chopping MethodField Restrictions Extended Objects Efficiency (exposure time) Comments Focal Plane Choppingfew arcsecsbad technical risk Pupil Plane Chopping~10 arcsecbad technical risk (AO challenging,) Dicke Switchingnonegood<0.5very good flat field calibration device; should be implemented in any case Nodding/Dithering?good (TBC) 0.15 (– 0.9?)will depend on detector, site and weather; needs testing of suitable fixed pattern noise filtering

Gratings Need ~1-m gratings for R ~ 100,000 spectroscopy  Directly ruled for longer wavelengths  Explore alternative grating technologies: Immersion gratings (development SRON) in silicon for L+M band? Volume Phase Holographic Gratings (development ATHOL and within OPTICON FP-6). Q: Are there now photosensitive materials transmissive beyond 2.5 μm?

Other Technology Developments Mirrors: 3-mirror astigmats require highly aspheric mirrors that can easily be made using diamond milling, but surface roughness too high for METIS. IR-Detectors: for mid-IR wavefront sensing (not science) Fibres: (not part of instrument baseline) Could be included if reliable, cryogenic fibres for λ < 13μm exist. New materials: (not part of the instrument baseline) light- weight and simplified cryostats? Coatings: filters and dichroics (UK involvement - U of Reading)

UK contribution The JWST-MIRI Spectrometer pre-optics (SPO) have been developed, built and tested by the UKATC. At the heart of the MIRI SPO are four all-reflective diffraction-limited integral field units. The METIS concept includes a requirement for high and medium spectral resolution IFUs similar to those in the MIRI SPO. We intend to build on the JWST-MIRI spectrometer pre- optics concept to support this area of the METIS Phase A study.

All aluminium design for ease of alignment. Slicer mirrors diamond finished by Cranfield University. The JWST-MIRI Integral Field Units

The complete MIRI SPO  m 8.63  m