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AIRS: The Antarctic Infrared Survey. James M. Jackson Institute for Astrophysical Research Boston University. Our Local Universe: Key Astrophysical Questions. Earliest stages of planet formation Nature and number of brown dwarfs Earliest stages of star formation.

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airs the antarctic infrared survey

AIRS: The Antarctic Infrared Survey

James M. Jackson

Institute for Astrophysical Research

Boston University

Sydney Zoo

our local universe key astrophysical questions
Our Local Universe:Key Astrophysical Questions
  • Earliest stages of planet formation
  • Nature and number of brown dwarfs
  • Earliest stages of star formation

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key science is uniquely addressed by thermal infrared observations
Key Science is Uniquely Addressed by Thermal Infrared Observations
  • Wavelengths of 3 to 30 mm correspond to black-body temperatures of 100 to 1000 K
  • Infrared emission probes cooler objects:
    • Protoplanetary disks
    • Brown dwarfs
    • Star forming regions

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RCW 38

Another essential advantage:

Infrared penetrates dust clouds

(M. Petr 2000)

VLT-FORS optical

VLT-ISAAC infrared (JHK)

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Lada 2002

why antarctica for infrared studies it s cold
Why Antarctica for infrared studies?It’s COLD!
  • Reduced infrared thermal background
  • Telescopes and atmosphere emit in the thermal infrared
  • Antarctic mean temperature ~ –50 C
  • IR backgrounds typically 20 to 100 times smaller than at temperate sites
  • Excellent sensitivity

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greatly reduced infrared sky brightness







Greatly Reduced Infrared Sky Brightness

The sky background is 20 – 100 times smaller at the South Pole compared with Mauna Kea

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Phillips et al. 1999

wide field infrared surveys are essential to study the local universe 2mass
Wide-field infrared surveys are essential to study the local Universe: 2MASS

2MASS 2mm


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wide field infrared imaging surveying large areas
Wide-Field Infrared Imaging: Surveying Large Areas
  • Discover huge numbers of new objects for follow-up by larger telescopes or interferometers
  • Obtain statistically significant samples
  • BUT 2MASS still suffers from extinction
  • Longer wavelengths penetrate dust better
  • There are no large-scale 3 mm < l < 5 mm surveys

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the antarctic infrared survey
The Antarctic Infrared Survey
  • The next generation Antarctic IR telescope
  • 2 meter aperture
  • 2-5 mm wide-field imaging camera
  • Essential step in eventual development of large (15 m) Antarctic IR telescopes and multi-element interferometers

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the antarctic infrared survey1
The Antarctic Infrared Survey
  • Simultaneous K and L band survey
  • 8,000 square degrees (d < -38o)
  • Same sensitivity at L-band as 2MASS at K-band (5s limiting magnitude of 15.0)
  • Detect all 2MASS objects with flat colors
  • Discover hundreds of thousands of redder objects

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formation of planets protoplanetary disks
Formation of Planets: Protoplanetary Disks
  • Dusty disks have temperatures perfectly matched to the thermal infrared.
  • Their presence can be inferred from excess IR emission.

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identifying protoplanetary disks with l band excess
Identifying protoplanetary disks with L band excess

L-band SPIREX data



Disks manifest themselves as excess L-band

emission (Kenyon & Gomez 2001)

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l and t dwarfs
L and T Dwarfs
  • Coolest stars and brown dwarfs are called “L and T dwarfs”
  • Boundary between stars and brown dwarfs is 0.07 solar masses

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ir color vs stellar type reddest objects are brown dwarfs
IR color vs. stellar type:reddest objects are brown dwarfs

Cooler (lower mass)


Brown dwarfs

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Burgasser 2002

how many l and t dwarfs will the antarctic infrared survey detect
How many L and T dwarfs will the Antarctic Infrared Survey detect?
  • AIRS will reach Llim=15.0, Klim =19.4 mag (tint = 9 minutes)
  • Survey 8,000 square degrees
  • L dwarfs
    • K-band detections ~350,000
    • L-band detections ~3,000 to 6,000
    • Increase known sample by factor of ~30
  • T dwarfs
    • K and L band detections ~16 to 32
    • Increase known sample by factor of ~2

Kirkpatrick et al. 1999

Burgasser 2001

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star forming regions 30 doradus
Star-forming Regions: 30 Doradus

SPIREX/Abu data

Blue: J, Green: K, Red: L

Deeply embedded stars show as red.

L-band detects deeply embedded YSOs undetected at K-band.

This is the world’s most sensitive ground-based L-band image (19 mag) taken with only a

60 cm telescope!

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airs scientific goal
AIRS Scientific Goal
  • To survey the sky in the thermal infrared in order to significantly increase the known samples of protoplanetary disks, brown dwarfs, and young stellar objects

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telescope design
Telescope Design
  • Cassegrain
  • 2 meter primary
  • f/1.6
  • 0.6 m secondary
  • 9.6% blockage
  • 42 arcmin field of view
  • Plate scale 58.18 mm/arcsec

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aircam camera design
AIRCAM Camera Design



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  • Simultaneous L and K band imaging
    • Registration
    • Cross-calibration with 2MASS
  • 2048 x 2048 InSb array for L and M bands
  • 1024 x 1024 HgCdTe array for K band

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expected optical performance strehl ratio vs field of view
Expected Optical Performance: Strehl Ratio vs. Field of View

Diffraction-limited performance out to edges of 20x20 arcmin AIRCAM field of view

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prototype spirex abu
Prototype: SPIREX/Abu
  • Every aspect of AIRS has been successfully demonstrated by SPIREX/Abu:
    • Telescope
    • Camera
    • Community Access
    • Data pipeline
  • AIRS requires no new technology

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the south pole site
The South Pole Site
  • Excellent, low sky backgrounds
  • Good, stable weather
  • Adequate, steady seeing
  • The South Pole site is extremely well characterized!
  • Excellent infrastructure and support
  • AIRS can achieve its technical requirements at Pole.

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dome c a better site
Dome C: A better site?

Compared with the South Pole, Dome C is

    • Higher
    • Less windy
  • May well have better sensitivity and seeing
  • Not at 90o S
    • More sky coverage
    • Better access to communications satellites


Site testing just beginning

Infrastructure not yet comparable

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another advantage of dome c land transport
Another Advantage of Dome C:Land Transport
  • Large pieces can be hauled in
  • Greatly reduces assembly time on ice

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  • Years 1 and 2 (Boston U.):
    • Detailed design
    • IR surveys with MIMIR at Lowell 72-inch
  • Years 3 and 4 (Boston U. + Lowell)
    • Procurement + construction
    • Prepare test site at Anderson Mesa, Arizona
  • Year 5 (Lowell):
    • Systems integration
    • Automation and remote operations
    • Comprehensive tests

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  • Complete conceptual design work 2003
  • Submit new proposal to US NSF Office of Polar Programs June 2004
  • Evaluate Dome C site-testing
  • Explore collaborations with French, Italians, Australians, and other partners

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  • An L-band survey is critical to bridge the gap between near- and mid-IR surveys.
  • Will revolutionize our understanding of protoplanetary disks, brown dwarfs, and star forming regions.
  • A 2-meter class telescope is the next step for Antarctic IR astronomy.
  • Essential step for larger telescopes and interferometers

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  • Key science well-suited to Antarctica
  • SPIREX/Abu demonstration
  • Optical design well-developed
  • Solid plan with low risk
  • Will work well at South Pole
  • May work even better at Dome C

AIRS concept is sound and ready to go.

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