an optical / ir observatory on the antarctic plateau

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 AElevation 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

CSTAR2008－ 2011

Kunlun StationJan 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

• 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

Major Relevant Features

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

[OI]6300,6364 (300km)

N 5200 (258km)

Zodiacal Light; Diffuse Milky Way light; Faint stars and galaxies

Sonic Radar – SNODAR, UNSW, CCAA

Dome C

Dome A

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 atDome 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.

Example ScienceCSTAR Data

An Exoplanet Candidate

Black dots: Raw data

Red dots:Data binned to 10 min interval

CSTAR – an array of 4 14.5 cm telescopes

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 EfficiencyDefine 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:

For an unresolved diffuse source:

D-Diameter of the telescopeW-Field of view of the cameraq-fwhm of the image (seeing or diffraction limit)B-Sky surface brightness

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 installedon Jan. 24, 2012. Astronomical operation began on March 15.

AST3 SN Survey/DES Overlap

Schedule: Installation in 2011-2012Survey Operation: 2012 – 2017

Data Products:

>2000 SNIa to z ~ 0.15Core-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

SDSS SouthernEquatorial Stripe

Tie region

Supernova Cosmology More precise Hubble diagram Peculiar motion of nearby galaxies Measurement of s8

Dark matter and neutrino properties

36Wang, 2007

Microlensing toward the LMC

Pop III SNe

Pop III SNe

AST3!!!

KDUST4.0KDUST2.5

Survey EfficiencyDefine 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:

For an unresolved diffuse source:

D-Diameter of the telescopeW-Field of view of the cameraq-fwhm of the image (seeing or diffraction limit)B-Sky surface brightness

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

May, 2010

VISTA bandsSDSS bands

IR Background

It is also noteworthy that there are summer time IR background measurement atDome 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

GRBs at z ~15 !?

Comparable to VISTA for point source3 times faster than VISTA for diffuse source

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 deg²a deep broad-band (Y, J, H, Ks) survey (212hr) covering the full 1.5deg² fielda narrow-band (180hr) survey covering the same region as the ultra-deep broad-band survey.

UltraVISTAThe 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 bandBlue: CFHTLS Red: UltraVISTA ultra-deep stripsYellow: 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, 1.66strip3: 149.70, 2.76, 149.83, 2.76, 149.83, 1.66, 149.70, 1.66strip2: 150.06, 2.76, 150.20, 2.76, 150.20, 1.66, 150.06, 1.66strip1: 150.43, 2.76, 150.57, 2.76 ,150.57, 1.66, 150.43, 1.66Column 2 (as labelled on the plot) is the location of the deep IRAC strip.

Hubble Ultra Deep Field

One Single KDUST Exposure

For Comparison: KDUST Reaches HUDF Depth at 750nm in 83 Hours for point sources and 251 hours for diffuse source

Supernova Survey in Antarctica

• 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 8-m 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

Site Year S10.7cm U B V R I

MJy

La Silla 1978 1.5 - 22.8 21.7 20.8 19.5

Kitt Peak 1987 0.9 - 22.9 21.9 - -

CTIO 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

mag arcsec-2

Dark time zenith night sky brightness

measured at various observatories

Mattila et al. 1996; Pilachowski et al. 1989; Walker 1987, 1988; Leinert et al. 1998; Krisciunas 1997.