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 m

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

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.)

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 µm offers the same angular resolution as µm.

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…)

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

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

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

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 ?

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.

Conclusions Why a 12m submm telescope at Dome C ? Unique THz windows Could perform Unique Science at 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).

Why a 12m submm telescope at Dome C ? Unique THz windows Could perform Unique Science at 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 ~ to 1mJy (~ confusion limit with 6.2” resolution): 110/field (requires ~ 100 hours with a 12m telescope) to 0.3 mJy: 200/field (50 hours with a 25m telescope) (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 ).