1. Vincent Minier - CEA Saclay/France Luca Olmi - INAF/Italy & UPR Nick Tothill - Exteter/UK and a growing ARENA submm team ALMA-type antenna potential for submm astronomy at Dome C: An Antarctic Submillimetre Observatory 75° 06' S - 123° 20' E - 3233 m

2. Credit: N. Schneider 450 µm 350 µm ~200 µm opens ! Chajnantor/ALMA Dome C Unique THz windows

4. PWV < 0.5 mm at Dome C (TBC) 25-50% winter time PWV~0.2 mm (<10% at Chajnantor)  200 µm opens 350/450 µm open 90% winter time + fraction of daytime (30-40% at Chajnantor) High stability & low skynoise expected at Dome C (10-50 times lower than at Chaj.)

5. Unique THz windows Mapping time:  (NEFD/Flux) 2 x 1/FOV  (NEP/De -  ) 2 /Flux 2 / 2 Map. time (12m) = 4 x Map. time (25m) at a given and . But PWV percentile and skynoise at 350 µm could compensate x4  over a yr, same amount of observations done. 12 m@200 µm offers the same angular resolution as 25m@450 µm.

6. Unique Science Planetary disk histories Star formation in the Galaxies and beyond (Chamaleon, Carina, LMC, starburst galaxies) Galaxy formation and evolution (CIB, census of star formation & AGN role) CMB - SZ below 2 mm (cluster of high-z galaxies) Transverse: Molecular spectroscopy (NII, CO…)

7. 200-450 µm 20 K T dust =40 K Luminosity Temperature Mass IMF Class 0-like high-mass protostar Unique Science

8. SCUBA 850  m Hubble Deep Field Hughes et al. 1998 3’ z=5 z=3 Unique Science

9. Star formation @200 µm: res.=0.1 pc, 1 deg 2 in a few days, sens.: 0.1 M  (10  ) @ 5 kpc CIB@350µm: 2.5 mJy (5-  ) over 1.3 deg 2 in 3600 hrs  2 winters

10. Unique pathfinder A 12m telescope for preparing future and larger facilities A >25m telescope (great for CIB) but wind, pointing and T° gradient issues at 200 µm A THz+mid-IR telescope (Olmi’s ASO) but mid- IR upgrade will delay the project 3 x 12m interferometer with short spacing –‘Simulate’ a 25m telescope –THz heterodyne (ALMA will not do it) –Bolometric interferometry to prepare FIRI space mission in the framework of ESA Cosmic Vision ?

11. Unique pathfinder Use ALMA design (Thales or Vertex) –As cheap (~10 M € ) as designing a 5m antenna (?) –Much cheaper than the cost of a 25m tel. (100 M€) –Can do very good science by 2014 Limited surface accuracy upgrade to a minimum (?)  design study on thermal effects (gradient and ~-70°C temperature) Prepare polar engineering to larger facility, e.g. an interferometer.

12. Conclusions Why a 12m submm telescope at Dome C ? Unique THz windows Could perform Unique Science at 200-450 µm Unique opportunity and pathfinder Happening now and to be done (roadmap): –Design study by industries –Environmental studies (GIVRE, wind…) for engineering –200 µm transmission & PWV to be measured (2008, 2009) –Skynoise at Dome C to be estimated and measured (CAMISTIC on a small telescope).

13. Why a 12m submm telescope at Dome C ? Unique THz windows Could perform Unique Science at 200-450 µm Unique opportunity (2014- ~10 M € ) and pathfinder to larger facility: Numbers of 350um (>5sigma) sources expected in a 10 arcmin^2 field with a 3.1’x3.1’ bolometer array; mostly high-z (z>1) sources, based on LeBorgne et al 2007 counts to 10mJy (plausible Herschel confusion limit): 8/field (requires ~ 1 hour with a 12m telescope) Lbol ~ 2x10^12 @z=2 to 1mJy (~ confusion limit with 6.2” resolution): 110/field (requires ~ 100 hours with a 12m telescope) Lbol~1.7x10^11 @z=2 to 0.3 mJy: 200/field (50 hours with a 25m telescope) Lbol~4x10^10 @z=2 (from E. Daddi) Great science case for a 3 x 12 m antenna interferometer Happening now and to be done (roadmap): –Design study by industries –Environmental studies (GIVRE, wind…) for engineering –200 µm transmission & PWV to be measured (2008, 2009) –Skynoise at Dome C to be estimated and measured (CAMISTIC on a small telescope - 2010).