Download Optical/Infrared Astronomy of AST3

An Optical / IR Observatory
on The Antarctic Plateau
Lifan Wang
George Mitchell Institute for Fundamental
Physics and Astronomy
Texas A&M University
Cook’s Branch, April 12, 2012
The Site
Dome A
Elevation 4,091 m (13,422 ft)
Coordinates: -80d22m, E77d 21m
The highest peak on the Plateau
A team of Pioneers led by Yuanshen Li of Polar Research Institute
Of China arrived at Dome Argus, Antarctica on Jan 18, 2005.
Dome A - 2008
China/Australia/USA
CSTAR
2008－2011
Kunlun Station
Jan 27, 2009
Scientific Considerations
• Time Domain Astronomy – Requires Clear Sky
• High Spatial Resolution, Wide Field Astronomy – Requires
Clear Sky, Good Seeing
• Wide Field Infrared Survey – Requires Clear Sky, Good
Seeing, and Low Sky Background
• Terahertz Telescope – Requires Low PWV
Major Relevant Features
•
•
•
•
•
Continuous observing time for more than 3 months
Low temperature, low sky background in thermo IR
Low turbulence boundary layers, good seeing
Dry air, high transmission in IR
Large Isoplanatic Angle
•
•
•
•
Aurora
High relative humidity
Difficult to access
Less dark time
Zou et al. 2010
Zou et al. 2010
Zou et al. 2010
•OH (near IR)
•O2 (IR+Herzberg,
Chamberlain bands)
•NO2 (pseudocont.)
•Na (seas. variation);
•Hg, Na lines
•Weak continuum
Zodiacal Light; Diffuse Milky Way light; Faint stars and galaxies
[OI]6300,6364 (300km)
N 5200 (258km)
Sonic Radar – SNODAR, UNSW, CCAA
Dome A
Dome C
Height of Turbulence Layer at Dome A & C
Boner et al. 2010
Precipitable Water Vapor
Nigel at Dome A – An instrument for sky emission
Nigel
Black spectrum: Hill & Jones JGR 105, 9421 (2000)
IR Background
It is also noteworthy that there are summer time IR background measurement at
Dome C (Walden et al. 2005). The summer time 3-20 m backgrounds were found
to be very stable and at levels comparable to the measurements at South Pole
during the winter.
CSTAR – an array of 4 14.5
cm telescopes
Example Science
CSTAR Data
An Exoplanet Candidate
Black dots: Raw data
Red dots:
Data binned to 10 min interval
d Scuti star
Uninterrupted 4.5-d light curve
(representing 3.5% of the entire data).
Folded light curve using P = 0.2193d; the
photometric uncertainty is 1.5 mmag/bin.
Lingzhi Wang, Lucas Macri et al. 2011
Survey Efficiency
Define the survey efficiency k as the sky area a telescope can survey to a given
S/N for a resolved source in a specific exposure time:
D-Diameter of the telescope
W-Field of view of the camera
q-fwhm of the image (seeing
or diffraction limit)
B-Sky surface brightness
For an unresolved diffuse source:
If the background is lower by a factor of 50-100,
as is the case for 2.4 micron at Dome A, a 0.5
meter telescope can survey as fast as a 3.5-5.0
meter telescope at a temperate site
A single KDUST field is 2 sq degree.
Antarctica Survey Telescopes
AST3
• 68/50cm Diameter
• FoV 4.2 Sq Deg
• 1”/pix
Standard Candles
Sensitivity
Sensitivity
The first AST3
telescope was installed
on Jan. 24, 2012.
Astronomical
operation began on
March 15.
AST3 SN Survey/
DES Overlap
Schedule: Installation in 2011-2012
Survey Operation: 2012 – 2017
Data Products:
>2000 SNIa to z ~ 0.15
Core-collapse SNe; GRB; Orphan GRB afterglow
LMC continuous monitoring
–variable stars/microlensing/dark matter
Galactic center continuous monitoring
– variable stars/microlensing/transients
Galactic structure
– RR Lyrae/Cepheids
SPT overlap
area
Tie region
SDSS Southern
Equatorial Stripe
Supernova Cosmology

More precise Hubble diagram

Peculiar motion of nearby galaxies

Measurement of s8

Dark matter and neutrino properties
Wang, 2007
36
Microlensing toward the LMC
Pop III SNe
Pop III SNe
KDUST2.5
AST3!!!
KDUST4.0
Survey Efficiency
Define the survey efficiency k as the sky area a telescope can survey to a given
S/N for a resolved source in a specific exposure time:
D-Diameter of the telescope
W-Field of view of the camera
q-fwhm of the image (seeing
or diffraction limit)
B-Sky surface brightness
For an unresolved diffuse source:
If the background is lower by a factor of 50-100,
as is the case for 2.4 micron at Dome A, a 0.5
meter telescope can survey as fast as a 3.5-5.0
meter telescope at a temperate site
A single KDUST field is 2 sq degree.
z=7 Quasar and VISTA Filters
SDSS bands
May, 2010
VISTA bands
IR Background
It is also noteworthy that there are summer time IR background measurement at
Dome C (Walden et al. 2005). The summer time 3-20 m backgrounds were found
to be very stable and at levels comparable to the measurements at South Pole
during the winter.
AST3 NIR
Synoptic Infrared Survey Telescope
In KDARK, compared to 2MASS, an increase
of efficiency by
(2048/256)2 * (0.5/1.3)2 * 50 = 473 times
Comparable to VISTA for point source
3 times faster than VISTA for diffuse source
GRBs at z ~15 !?
Kunlun Dark Universe Telescope
Intermediate Scale Project
Supernovae
Weak Lensing
Strong Lensing
BAO?
PILOT/KDUST Sensitivity
UltraVISTA is an Ultra Deep, near-infrared survey with the new
VISTA surveys telescope of the European Southern Observatory
(ESO). Over the course of 5 years, UltraVISTA will repeatedly
image the COSMOS field in 5 bands resulting in three key
surveys:
anultra-deep broad-band (Y, J, H, Ks) survey (1408hr) covering
0.73 deg²
a deep broad-band (Y, J, H, Ks) survey (212hr) covering the full
1.5deg² field
a narrow-band (180hr) survey covering the same region as the
ultra-deep broad-band survey.
UltraVISTA
The position of the UltraVISTA ultra-deep broad band and
narrow band survey overlaid on the KPNO Ks image of the
COSMOS field. The x and y axes are RA and Dec respectively.
The coloured outlines are as follows:
Green: ACS I band
Blue: CFHTLS
Red: UltraVISTA ultra-deep strips
Yellow: UltraVISTA ultra-deep strips with 1 arcmin trimming
(trimmed due to incomplete coverage from
dithering)
The coordinates of the corners of the ultra-deep field
(yellow boxes) are (in decimal RA and Dec):
strip4: 149.33, 2.76, 149.46, 2.76, 149.46, 1.66, 149.33, 1.66
strip3: 149.70, 2.76, 149.83, 2.76, 149.83, 1.66, 149.70, 1.66
strip2: 150.06, 2.76, 150.20, 2.76, 150.20, 1.66, 150.06, 1.66
strip1: 150.43, 2.76, 150.57, 2.76 ,150.57, 1.66, 150.43, 1.66
Column 2 (as labelled on the plot) is the location of the deep
IRAC strip.
One Single KDUST Exposure
For Comparison: KDUST Reaches HUDF Depth at 750nm in
83 Hours for point sources and 251 hours for diffuse source
Hubble Ultra Deep Field
Supernova Survey in Antarctica
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•
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4 meter Aperture
1-3.5 micron coverage
5000 supernovae up to z ~ 2 (rest frame NIR)
2000 supernovae with z ~ 2-4 (unexplored
territory)
• JWST target feeder for spectroscopy and
photometry
• E-ELT/GSMT target feeder for spectroscopy
(photometry?)
Zhao et al. 2010, PASP
Zhao et al. 2010, PASP
Zhao et al. 2010, PASP
The exposure time
required to obtain S/N
= 5 five rest frame
days after explosion
for a canonical
supernova using an 8m telescope at Dome
A. Note the change in
scale between the two
plots.
10 rest frame days
after explosion
The exposure time required to type a canonical
supernova using an 8-m telescope at Dome A,
with S/N = 5 in a λ/δλ = 150 element for the
restframe 0.615 μm SiII feature. The restricted
redshift range corresponds to when the line is
within the Kdark window.
Summary
1. Dome A site survey is going on, so far so
good
2. The first of the AST3 triplet is installed and
is in science operation
3. A pathfinder telescope is needed before
we can build a larger telescope
4. KDUST2.5 can make a significant
contribution to cosmology
5. KDUST4.0 working primarily in the NIR will
provide deep maps of the universe
Dark time zenith night sky brightness
measured at various observatories
Site
Year
S10.7cm
U
B
V
R
I
mag arcsec-2
MJy
La Silla
1978
1.5
-
22.8
21.7
20.8
19.5
Kitt Peak
1987
0.9
-
22.9
21.9
-
-
1987-8
0.9
22.0
22.7
21.8
20.9
19.9
Calar Alto
1990
2.0
22.2
22.6
21.5
20.6
18.7
La Palma
1994-6
0.8
22.0
22.7
21.9
21.0
20.0
Mauna Kea
1995-6
0.8
-
22.8
21.9
-
-
Paranal
2000-1
1.8
22.3
22.6
21.6
20.9
19.7
CTIO
Mattila et al. 1996; Pilachowski et al. 1989; Walker 1987, 1988; Leinert et al. 1998; Krisciunas 1997.