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Wide field HAR imaging surveys in the thermal infrared (3-5 µm) from Dome C

Wide field HAR imaging surveys in the thermal infrared (3-5 µm) from Dome C. Nicolas Epchtein CNRS/LUAN/UNSA. Main goals. Extend 2MASS/DENIS and VISTA/UKDISS Deeper Toward longer l : K dark , L short , L’, M’(NQ) Complete Spitzer; ASTRO-F; WISE Better angular resolution

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Wide field HAR imaging surveys in the thermal infrared (3-5 µm) from Dome C

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  1. Wide field HAR imaging surveys in the thermal infrared (3-5 µm) from Dome C Nicolas Epchtein CNRS/LUAN/UNSA workshop_wide_field_140606

  2. Main goals • Extend 2MASS/DENIS and VISTA/UKDISS • Deeper • Toward longer l: K dark, L short, L’, M’(NQ) • Complete Spitzer; ASTRO-F; WISE • Better angular resolution • Remove confusion limit (Spitzer/WISE) • Imaging Surveys of selected large targets: Magellanic Clouds (global monitoring); Bulge /Disk sample (ISOGAL); Nearby Large Molecular Clouds & SFR (Cham, Carina,..); Deep Fields for extragalactic and cosmology/ nearby very low mass stars • Provide astrometric/photometric catalogues to JWST workshop_wide_field_140606

  3. Questions • science case to extend large scale infrared sky surveys (VISTA-like) beyond 2.3 µm (ARENA 5.1)? • Are the future space missions ASTRO-F; WISE; JWST opportunities? • Does Dome C provide the appropriate response? • If yes, what are the top level requirements ? • What is achievable at Dome C within the next decade ? • Long range: small ELT (20 m class) dream or reality ? workshop_wide_field_140606

  4. Reflections on an: «Antarctic Mid-Infrared Deep Survey Telescope» (AMIDST) workshop_wide_field_140606

  5. General remark • No High Angular Resolution large scale surveys > K • K-L’ index is a simple and efficient test to select dusty objects, in general, much more efficient than IJHK colours workshop_wide_field_140606

  6. From Maercker & Burton, 2005, see also Burton et al. PASA 22, 199 workshop_wide_field_140606

  7. L’ L short Ks Kdark workshop_wide_field_140606

  8. K-L index is a powerful tool to evaluate the Mass loss From Le Bertre and Winters, 1999 workshop_wide_field_140606

  9. From Golimowski et al, 2004 Classification of Brown dwarfs L and T brown dwarfs K-L’ colours workshop_wide_field_140606

  10. From Cioni et al., ESO Messenger March 2004 workshop_wide_field_140606

  11. 3-5 µm surveys science impact • FREE-FLOATING PLANETS IN STAR CLUSTERS and in the field • Small bodies of solar system (Kuiper belt) • EMBEDDED YOUNG STELLAR OBJECTS • EARLY PHASES OF STELLAR EVOLUTION • MICROLENSES: OPTICAL AND NEAR-INFRARED COUNTERPARTS • New inputs for: • ISM (HAR spectro-imaging in 2-5 µm range) • THE STELLAR INITIAL MASS FUNCTION • THE INTRACLUSTER STELLAR POPULATION • THE COSMIC STAR FORMATION RATE • YOUNG, MASSIVE STAR CLUSTERS • YSOs/ late stellar AGB populations of clusters, MCs, nearby galaxies • Cosmological interest (galaxies large z …) window at 4 µm • Provide 3-5 µm catalogues for future space missions (JWST) • Follow up of WISE improving AR and confusion workshop_wide_field_140606

  12. No deep survey can be carried out from the ground beyond 2.3 µm because of: • Sky emission brightness K=12/13 at M. Kea • Sky emission instability • Instrumental thermal emission (250-300K) • BUT from Polar sites workshop_wide_field_140606

  13. From Lawrence et al. (2001) Atmospheric emission between 2 et 5.5 µm workshop_wide_field_140606

  14. Sky background measured above South Pole and Mauna Kea • in mJy/arsec2 and magnitudes/arcsec2 (approx.) • (1)from : Ashley et al. 1996, Nguyen et al. 1996, Phillips et al. 1999, Burton et al., 2001 workshop_wide_field_140606

  15. workshop_wide_field_140606

  16. L’ M’ From Storey et al. J H K H20 = 1mm; 1 airmass Kdark L short 250 µm 800 µm Atmospheric transmision between 1.2 et 5.5 µm workshop_wide_field_140606

  17. Atmospheric turbulence parameters From Trinquet et al. 2006 workshop_wide_field_140606

  18. Focus on the spectral range whereAntarctic conditions provide: • A maximum gain in sensitivity in a relatively poorly explored spectral range • Low and stable sky background • Low instrumental emission (passive cooling) • Excellent atmospheric transmission • Large isoplanetic angle and good seeing workshop_wide_field_140606

  19. Low sky and instrumental background • Optimized for thermal IR at diffraction limit IT ~ Bl (q/D2) q angular resolution At diffraction limit: IT ~ Bl /D4 point source Extended souces: IT~ Bl /D2 (source size>seeing) Seeing limited  AO depends on isoplanetic angle qo workshop_wide_field_140606

  20. A 3 m AMIDST would be the best 2.3-5.5µm imaging survey facility on the ground • Equivalent to a 12 m telescope for extended sources > seeing in the thermal range • Wide field (1 –2°)/Switchable SF (DCT concept) workshop_wide_field_140606

  21. Which strategy • IRAIT 80 cm and beyond? • PILOT-like 2.5 m class multipurpose • Antartized NTT? • WF-IR 4 m class telescope (VISTA, DCT)? • 8 m class (LSST class) • Or even larger? (GMT 7x 8 m) • dedicated IR Imaging survey or more general purpose telescope? • Spectro-imaging capability workshop_wide_field_140606

  22. A wide field imaging survey dedicated telescope «AMIDST»Antarctic Mid Infrared Deep Survey Telescope • Objective (requirements): • Gain > x10 / Spitzer (IRAC/Glimpse) @ K and L • Gain 5 to 10 in angular resolution / Spitzer/WISE • FOV > 1° • Pixel size ½ diffraction limit at L (3m) 0.3 arcsec • optics/coatings optimized at 3-3.8 µm • Low emissivity configuration • Passive cooling optimized • Survey: thousands square degrees in standard mode & a few hundreds in deep mode • large FPA covering ~ 1 sq. deg. (16 x 2kx2k) workshop_wide_field_140606

  23. A single dish telescope • Wide field 3-meter at Dome C would match the requirements • Australian PILOT (2.4m) • AO simple (to qo ) • off axis primary ?(low emissivity, no diffraction/ High contrast photomery) • Passive cooling at 200-220K • Day (5+µm) /night (2-5 µm) operations • High level of robotisation (remote control telescope & focal equipment) workshop_wide_field_140606

  24. Discovery Channel Telescope (DCT) Lowell FOV 2° 4m Flagstaff Large Synoptic Survey Telescope 8.4-meter Cerro Pachon 10° FOV 2012 VISTA workshop_wide_field_140606

  25. A multi-mirror telescope ? • 6 dishes of ~ 2-3-8 m f/2 or faster (f/1!) • Low emissivity / no secondary diffraction • Very compact – easily movable • Allows 6 instruments simultaneously on same field!. • Possibility of beam recombination – interferometric capability • Exemples: • LPT concept (NG-CFHT)/ New Planetary Telescope (small version) • GMT (Angel et al., 7 dishes of 8 m) workshop_wide_field_140606

  26. Giant Magellan Telescope 7 mirrors 8 m • High Dynamic range telescope for NG-CFHT • 6 x 8 meter • From Kuhn & Moretto, et al. 2001 workshop_wide_field_140606

  27. IR focal   equipment for AMIDST » • Multicolour observations • IR camera(s) (4 k x 4 k or more) K dark, L s , L’, M’ • (e.g., HgCdTe Hawaii 2RG or InSb Aladdin) • no « warm» optics • cooled dichroïc beamsplitters • optimised for each channel • Maximum efficiency. • FOV 32’ x 32’ or 16’ x 16’ (or more) • scale : 0.48 / 0.24 arcsec. (diffraction of a 3 m @ 3.8 µm = 0.65 arcsec ) • possibly 10-25 µm camera (SiAs) & even beyond • IFTS (1.25-5 µm) workshop_wide_field_140606

  28. workshop_wide_field_140606

  29. Point source sensitivity of a WF survey 3 m telescope at Dome C (diffraction limited) • Aperture: 3 m • FOV = 16’ x 16’; pxl. scale = 0.24’’ ; • Thruput = 30% • Deep ‘standard’ Survey • exposure = 30 s per field • 1000 sq. deg. covered in 150 h ( 5 « days ») • Very deep survey (Kd et L’) • exposure = 30 mnper field • 100 sq. deg. covered in some 35 « days » workshop_wide_field_140606

  30. Detection limit (5s)é point source Passively cooled 200K and low background telescope (e = 1%) Hypothesis: diffraction limited, AO; charge capacity : 2.5 105 e- (italics): same telescope at best tropical site (1) Saturated by sky emission in 100ms workshop_wide_field_140606

  31. Antarctica Space Ground deeply embedded 1 Lprotostar atdistance 0.6 kpc 0,01 AMIDST std T Tauri star at a distance of 0.7 kpc VISTA 0,001 AMIDST deep workshop_wide_field_140606

  32. timeline • Complete site testing (2005-2008) • First experience with IRAIT (2008) • Feasibility study of a PILOT like 3m (2007-8) • Raise funding thru International sharing of costs (e.g. EC FP7, ESO, Australia + National Agencies+ Polar Institutes) (2007) • Working group in ARENA to work out detailed sc. case and optimize TLR (2006-2008) •  New infrastructure partly funded by FP7 (2007) • Manufacturing: 2009-12 - Mirror 2008-2011 • set up on site: summer 2012-13 • first light: winter 2014 workshop_wide_field_140606

  33. Concluding Remarks • Dome C: best ground based thermal infrared site • 2.3-5 µm is the optimal spectral range for Dome C • WF deep HAR imaging surveys:strong science case • Little risk. Don’t need further site testing. Start immediately design studies (PILOT ?) • Main features: • FOV 1° minimum (Prime or RC? Corrector) • Aperture  3m minimum • Low emissivity and optimal passive cooling • Arrays: 1° field + diffraction limit  16 x 2k arrays  4 MUSD • first light by 2014 • 20 m GMT like telescope is « the » OWL telescope workshop_wide_field_140606

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