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

workshop_wide_field_ Main goals Extend 2MASS/DENIS and VISTA/UKDISS –Deeper –Toward longer : 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_ 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_ Reflections on an: «Antarctic Mid-Infrared Deep Survey Telescope» (AMIDST)

workshop_wide_field_ 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_ From Maercker & Burton, 2005, see also Burton et al. PASA 22, 199

workshop_wide_field_ K dark L short L’ KsKs

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

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

workshop_wide_field_ From Cioni et al., ESO Messenger March 2004

workshop_wide_field_ 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_ 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 ( K) BUT from Polar sites

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

workshop_wide_field_ Bande  m South Pole (1) mJy/arcsec2 mag Mauna Kea mJy/arcsec2 mag KsKs KdKd L’ M’ N in mJy/arsec 2 and magnitudes/arcsec 2 (approx.) (1) from : Ashley et al. 1996, Nguyen et al. 1996, Phillips et al. 1999, Burton et al., 2001 Sky background measured above South Pole and Mauna Kea

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workshop_wide_field_ Atmospheric transmision between 1.2 et 5.5 µm KHJ L’ M’ H 2 0 = 1mm; 1 airmass K dark L short From Storey et al. 250 µm 800 µm

workshop_wide_field_ Sites  (arcs)  (ms) seeingIsoplanetic angleCoherence time La Silla Paranal Pachon Maidanak Mauna Kea San Pedro South Pole Dome C(0) H> 30m From Trinquet et al Atmospheric turbulence parameters

workshop_wide_field_ Focus on the spectral range where Antarctic 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_ Low sky and instrumental background Optimized for thermal IR at diffraction limit IT ~ B (  /D 2)  angular resolution At diffraction limit: IT ~ B /D 4 point source Extended souces: IT~ B /D 2 ( source size  seeing) Seeing limited  AO  depends on isoplanetic angle  o

workshop_wide_field_ A 3 m AMIDST would be the best µm 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_ 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_ A wide field imaging survey dedicated telescope «AMIDST» Antarctic Mid Infrared Deep Survey Telescope Objective (requirements): –Gain > x10 / Spitzer 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 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_ A single dish telescope Wide field 3-meter at Dome C would match the requirements –Australian PILOT (2.4 m ) –AO simple (      – off axis primary ?(low emissivity, no diffraction/ High contrast photomery)  Passive cooling at K  Day (5 + µm) /night (2-5 µm) operations  High level of robotisation (remote control telescope & focal equipment)

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

workshop_wide_field_ A multi-mirror telescope ?  6 dishes of ~ 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_ High Dynamic range telescope for NG- CFHT 6 x 8 meter From Kuhn & Moretto, et al Giant Magellan Telescope 7 mirrors 8 m

workshop_wide_field_ 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 µm = 0.65 arcsec )  possibly µm camera (SiAs) & even beyond  IFTS ( µm)

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workshop_wide_field_ 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 (K d et L’) exposure = 30 mn per field 100 sq. deg. covered in some 35 « days »

workshop_wide_field_ AMIDST «standard » Survey AMIDST « deep» Survey SPITZER (IRAC) (Glimpse) WISE Pxl = 5’’ VISTA Antarctica 3 mSpace 80 cmspace 40 cmParanal 4 m Int.Time30s30 mn1 sec K diffract. 0.4’’1.4’’2.5 ’’0.28 ’’ KdKd 21.8 (17.9) 25.8 (20.1) n.a (5000° 2 ) 21.5 (100° 2) At K short L’16.5 (13.7) 18.7 (15.8) n.a. M’13.3 (10.7 ) 14.5 (1) n.a. Detection limit (5 s ) é point source Passively cooled 200K and low background telescope (  = 1%) Hypothesis: diffraction limited, AO; charge capacity : e - (italics): same telescope at best tropical site (1) Saturated by sky emission in 100ms

workshop_wide_field_ ,01 0,001 VISTA AMIDST std AMIDST deep deeply embedded 1 L protostar atdistance 0.6 kpc T Tauri star at a distance of 0.7 kpc Ground AntarcticaSpace

workshop_wide_field_ timeline Complete site testing ( ) First experience with IRAIT (2008) Feasibility study of a PILOT like 3 m (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 ( )  New infrastructure partly funded by FP7 (2007) –Manufacturing: Mirror –set up on site: summer –first light: winter 2014

workshop_wide_field_ Concluding Remarks Dome C: best ground based thermal infrared site 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 m GMT like telescope is « the » OWL telescope