1. A telescope for an ANtarctica Imaging & Survey
Extragalactic Studies on Galaxy Evolution with a Wide Field Optical/IR telescope on Dome C
A telescope
for an
ANtarctica
Imaging &
Survey
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

2. Outline
Interesting characteristics of Dome C from an astronomer working in the topic of galaxies
Definition of the science project and how to carry it out
Conclusions
Optical and Infrared Wide-Field Astronomy in Antarctica
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3. Atmospheric Emission (Burton et al. 2005)
~200 m
Bands
@ 350, 450 m ?
Optical and Infrared Wide-Field Astronomy in Antarctica
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4. Thermal Emission at South Pole and Mauna Kea
 for the same S/N: DDome C ≥ 3  Delsewhere (ground-based)
Band
l m)
South Pole (1)
Mauna Kea Ks
2.15
0.15
16.5 3
13.4 Kd
2.4
0.3
15.6 6
12.4 L’
3.8
100
8.6
2000
5.3 M’
4.8
1000
5.4
2.104
2.1
SB
+3.2
+3.3
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
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

5. Exceptional Natural seeing: ~ 300 mas above an altitude of ~ 30 - 50m
Lawrence et al. (2004)
Exceptional Natural seeing: ~ 300 mas above an altitude of ~ m
Wide Isoplanetic Angle: ~ 6 arcsecs in visible
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

6. Agabi et al. (2006) Balloon @ 30m 2.0’’ 1.5’’ 1.0’’ 0.5‘’ 0.0’’
Optical and Infrared Wide-Field Astronomy in Antarctica
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7. Characteristics of Dome C
Very cold (average -50°C down to -90°C)
Very far away
Dry atmosphere (250 m)
Superb natural seeing (above ~30m)
Wide isoplanetic angles (up to arcmin-sized in NIR)
Long coherence times (+ isoplanetic angles   # NGS)
Long « nights »  continuous observations
High stability (clear skies for 74% of the time in winter)
GOOD / BAD
Very cold (average -50°C down to -90°C)
Very far away
Boreal aurorae (but close to geomagnetic South Pole)
Tough conditions
Human psychology
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

8. What path for Extragalactic Antarctica Astronomy ?
Given the known characteristics of Dome C
Given the known characteristics of galaxies
Given the (ground-based or space) facilities already in use or in (already funded) project
Assuming that any type of project must be (relatively) cheap
Is there a « niche » that would provide Original Data to (at least) galaxy people ?
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

9. Parameter Space for Galaxy Studies
Range
Related Science (not exhaustive)
Field of View
≤ 1 arcmin (down to few arcsecs)
Individual high-z galaxies
Few (2-4) arcmins
Deep Fields
Several (10-20) arcmins
Local galaxies, small surveys
 1 sq. degree
Surveys
Spectral Resolution
Imaging (R < 5)
Morphology
SEDs (R ~ few 10)
SFR, SFH, …
Low resolution (R ~ few 100)
Redshifts
Intermediate resolution (R ~ few 1000)
Line ratios (Balmer decrement, abundances, …)
High resolution ( R > 5000)
Dynamics, line profiles
Angular Resolution (in visible)
Diffraction limited
Stellar populations,
 ~ 200 mas
Morphology at high z
~ 1 arcsec
Multi-wavelength analysis low-z
Wavelength Range
Optical ( um)
SFR, SFH, line diagnotiscs
NIR ( um)
Mass, high-z
MIR ( um)
PAH, AGN / starburst diagnostics
FIR ( um)
SFR, dust, AGN/ starburst diagnostics
Sub-mm (< 1 mm)
SFR, dust
Others : cost, PSF stability, temporal resiolution, Strehl ratio / EE, interferometry, coronography, …
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

10. What are we left* with ? *color coding can be further discussed…
Wide field of view (Ø ~1 deg)
Optical / NIR
High angular resolution (but not diffraction-limited in visible)
Imaging / SED (/ Spectroscopy)
Operations : the simpler the better
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

11. What do we need ? Telescope M1: Ø ~ 3m
An optical design for a wide field telescope providing < ~1/4’’ PSF ?
Can we build a telescope on top of a 30-50m tower ?
What if we can’t ? Some kind of AO ?
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

12. For instance : Optical Design from Gérard Lemaître
Dprimary = 2 - 3m
Wide FOV ~ 1 deg2
0.3 <  (m) < 1
Size of spot: 0.25’’ RMS
Room for AO ?
Behavior at  > 1m ?
Optical and Infrared Wide-Field Astronomy in Antarctica
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13. How to get rid of the turbulent ground layer ?
Build some sort of light and stiff 30 to 50m high tower ?
h=30-50m
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

14. I recommend not using palm-trees !
If that proves possible, it is probably the simple way to reach the specifications but …
I recommend not using palm-trees !
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

15. Wider isoplanetic angles
From Aristidi et al. (2006):
0 (Dome C) ~6 arcsec  3 x 0 (Other sites)  x 10 probability of finding NGS in visible
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

16. Even wider in NIR 0 (Dome C): ~ 6 arcsecs @ 0.5m
0 (Dome C): ~ 1/2 2.2m
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

17. GLAO Simulations are being carried out by ONERA (Thierry Fusco)
Adaptive optics enable large telescopes to provide diffraction limited images, but their corrected field is restrained by the angular decorrelation of the turbulent wave-fronts.
However many scientific goals would benefit a wide and uniformly corrected field, even with a partial correction.
Ground Layer Adaptive Optics (GLAO) systems are supposed to provide such a correction by compensating the lower part of the atmosphere only.
Indeed, this layer is in the same time highly turbulent and isoplanatic on a rather wide field.
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

18. Point source sensitivity of a WF survey (borrowed to Nicolas)
Aperture: 3 m
pixel scale = 0.24’’
Throughput = 30%
Deep ‘standard’ Survey
30 sec per field
1000 deg2 in 133h or « 5 days »
Very deep survey (Kd et L’)
30 min per field
100 deg2 in 35 « days »
Diff
(arc sec) 3m
« standard »
Survey
(?000 sq deg)
S/B = 5
« deep» Survey
(?00 sq deg.) Kd
0.35
21.8
(17.9)
25.8
(20.1) L’
0.65
16.5
(13.7)
18.7
(15.8)
Passively cooled 200K and Low background telescope (e = 1%)
Diffraction limited, AO
Green italics: same telescope at best tropical site
NICMOS HDF-N
Limiting magnitudes:
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

19. Complementary to SWIRE (7 fields 65 deg2) & WISE (All-sky survey)
Antarctica
« standard »
Survey
« deep» Survey
SPITZER (IRAC)
(SWIRE)
WISE
VISTA
3 m
space
80 cm
space 40 cm
Paranal 4 m
Int.time
30s
30 mn
1 sec
Spatial
resolution
0.4’’ (Limited by diffraction at 2 microns)
1.4’’
5’’ per pixel
~ 0.7 ’’ Kd
21.8
(17.9)
1.3Jy
25.8
(20.1) 0.03Jy
n.a.
19, 21, 22
At K short L’
16.5
(13.7)
62.5Jy
18.7
(15.8)
8Jy
19.0
7.3Jy
15.3
(140Jy)
Green: same telescope at best tropical site
NICMOS HDF-N
Limiting magnitudes:
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

20. OH suppressors studied at OAMP/LAM (jean-luc.gach@oamp.fr for details)
Sky brightness at 650 nm << 2.2 μm dominated by OH emission will be essentially identical at Dome C to that at all other observatory sites, including Mauna Kea (Kenyon & Storey 2006)
Decreasing OH airglow -> increasing SNR (by a factor of 2) but also increasing maximum exposure times before saturation -> better efficiency
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

21. Multiband filters studied at OAMP/LAM (jean-luc. gach@oamp
Multiband filters studied at OAMP/LAM for details)
Lebrun et al. (1998) designed to detect LBGs at z ~ 3
Can be also be done in NIR
Gain in exposure times -> better efficiency
No need to frequently change filters
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

22. What would be the « killer » science case of the Antarctica Imaging Survey (ANIS) ?
SDSS/VISTA-like survey (several thousands deg2)
with JWST-like angular resolution (about 0.2’’)
from visible to near-infrared wavelengths
Galaxy Formation & Evolution (morphology, SEDs, photometric redshifts, …)
Cosmology (cosmic shear, large scale structures, …)
Galactic plane (stellar evolution and star formation)
(Extra-)Solar system bodies
Optical and Infrared Wide-Field Astronomy in Antarctica
09/12/ :16

23. FIR/sub-mm prospective must not be forgotten
IRAS discovered Ultra Luminous IR Galaxies (ULIRG)
Are there any Ultra Luminous Sub-mm Galaxies (ULSG) ?
First All-Sky survey in the sub-mm range
Optical and Infrared Wide-Field Astronomy in Antarctica
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24. Conclusions
We propose a 2-3m visible - NIR (MIR) telescope that includes GLAO, a OH suppressor device and multi-band filters to carry out a SDSS/VISTA-like survey with JWST angular resolution : ANIS
Must start soon to be useful for JWST, SPICA, ALMA
More to come before Roscoff (hopefully)
Think about a funding strategy (especially in Europe)
Optical and Infrared Wide-Field Astronomy in Antarctica
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25. Dome C Let’s dream … Dome C / visible Dome C / near-IR Dome C / sub-mm
Optical and Infrared Wide-Field Astronomy in Antarctica
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26. M e r c i
Dome C
Optical and Infrared Wide-Field Astronomy in Antarctica
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