1. Construction of the Antarctic 10-m THz Telescope
TGSW2016 session#6
"Universe Evolution and Matter Origin"
Construction of the Antarctic 10-m THz Telescope
NAKAI Naomasa
University of Tsukuba

2. Search for “dark galaxies” which cannot be seen in optical
Galaxies are the mother’s body of stars
and planets which are sources of life.
age of the universe
13.8 billion yrs
-When and how were the galaxies born?
Unknown, unobservable
Observations with existing telescope
A billion yrs
-How and why have the galaxies
evolved in different types?
1 billion yrs
Elementary particle and nuclear
physics studies
Big Bang
Formation of
First stars and galaxies
ダスト

3. THz, submm, mm are best to detect extremely distant galaxies
at z~0
Most of galaxies are originally the brightest in the infrared radiated from dust heated by light from stars.
4.9Gyr
receding according to expansion of the universe
11.5Gyr
observed
12.5Gyr
Emission is redshifted.
Galaxies observed on the earth are the brightest at THz to mm.
13.2Gyr
galaxy
formation?
13.5Gyr
Spectra of THz to mm determine the redshift of the galaxies. mm
submm
THz
infrared
→ optical
Antarctic 10-m telescope

4. (e.g.) galaxies observed
Color:
Optical image (Hubble Space Telescope)
Z=0.25
(2.9Gyr)
Look back time
Contours:
submm image (SCUBA)
350 GHz = 850 μm
　 θ = 14”
Z=2.56
(11.0Gyr)

5. Plateaus in Antarctica are best to observe THz, submm (mm)
THz, submm (mm) are best to detect extremely distant galaxies,
but absorbed by water vapor in the atmosphere.
Atacama desert in Chile
at 5000 m (ALMA site)
= best at present
Precipitable water vapor
2012
2013
Ridge A
South Pole
(2835m) 〇 〇
Dome C 〇
(3260m)
Ridge A
Altitude 3000 – 4000 m
Mean temperature <－50℃
Lowest temperature －80℃
Clear sky always
Weak wind
summer
winter
2013 day#
Kulesa (2013)

6. Concordia station @ Dome C
Visited in Jan. & Feb. 2016
only for summer group
summer camp
airport runway
ASTEP
Main building
electric power line
communication line
80cm optical &IR
Antarctic 10-m THz telescope
・diameter ~ 10 m
・weight ~ 100 ton
・freq: 200~1500 GHz
・best resolution: 5”
・field of view: max. 1 deg
・continuum observations
spectral line observations

7. Transportation Italian ship, ITALICA plane Australian station plane
Dome C
Australian
station
plane ●
130 m x 17.3 m
GT ton
60 people max.
USA sta.
snow
tractor ●
Italian sta. ●
USA’s plane
Italian ship
plane
Navigation:
　　Christ. → Italian sta.
at least 7 days
(vomited/spewed 4 times!) ●
French
sta.
people
researchers
Heavy
goods
ship
thick ice in the sea
near the station
→ a helicopter
Christchurch (NZ)
Hobart (Austra.)
Japan

8. Italian station on the coast → Concordia station at Dome C
transfer station
refueling
a runway
oil drums
a bulldozer
no building
no ground staff
a copilot ↓
3.5 hrs
captain→
flight attendant (woman)　
Italian station
on the coast
Douglas DC-3
a best‐selling plane before
the world war II !
The above plane was made
after the war.
30 min
Twin Otter
Temperature ~ -2℃ ! (outside)
~ +20℃ ! (inside)

9. Concordia station @ Dome C
(inside)
+20~24℃
2016 Jan.-Feb.
Temper. (outside)　－28℃～－45℃
short-sleeved!
offices→
recreation room
←dining room
bed rooms→
(16)
←warehouse
↓power generator
entrance
250 ton /building
Extremely dry
Often drinking water

10. Used water is recycled.
→　a shower every day!
laundry anytime!
although drinking water is made from snow.

11. A weather tower Height ~ 40m a year electric power line
communication line

12. Small telescopes 80cm optical & IR Observing room ←empty
2m submm telescope

13. construction machinery
Construction period in summer
70 days
construction machinery
130 ton crane
Vehicle for work at height of 15m
4.6 ton crane
ケースーボーラPB300(snow clearing)

14. Snow base for the antenna
Main buildings
～100 ton
250 ton
250 ton →
・jack-up system + spacers（<1mm）
・measuring the inclination
・feed-back the inclination by software
・height of the antenna base ～2m
・surrounding by insulating material
・dig snow by 3m
・leveling of ground
・covering with snow
・hardly pack the snow
・repeat the process for 3 or 4 years
・use legs having large area

15. Transportation in the inland
ケースボーラーPB300
CAT tractor
Remove snow
Construct a road
pulling power 60 ton
sleighs

16. A jumbo jet C17 Australian air force 4.5 hours Hobart (Australia)
Farewell party
Dome C → DC 3 → Austr. station on the coast
A jumbo jet C17
Australian air force
4.5 hours
Hobart (Australia)

17. Time Schedule of Construction
Fiscal year of Japan (April – March) 20 16 17 18 19 21 22 23 24 25 26
Negotiating with
government
(construction budget)
(operation budget)
Request con. budget
to government
Start construction
Antenna:
Tower:
Construc. in Japan
Test in Japan To
Ant.
Construc.
at CCS.
Evaluation & test
observations *
Antenna Base:
Construc.
in Japan To
Ant.
Construc.
at CCS.
(Observ. Building:)
Construc.
at CCS.
Receivers/
cameras:
making/test in Japan
To Ant.
Set at CCS
To Ant.
Set at CCS
(*Antenna company is decided by competition)
Request oper. budget

18. Summary Operation of the Concordia station is very good.
Construction machinery is satisfied.
-130 ton crane, vehicle for work at height of 15m
The construction period is limited to be 70 days in summer.
Components of the antenna can be transported.
Technique to construct the snow base is fine.
Speed of satellite communication (Iridium, Inmarsat) is 512 k Bit/s
which may not be enough. Japan side may add a line. ⇒
It would be possible to construct the 10-m THz telescope at the station, although detail consideration is required.
Life at the station is comfortable, especially in water supply.