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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

Sydney Zoo

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

Sydney Zoo

James jackson

RCW 38 Observations

Another essential advantage:

Infrared penetrates dust clouds

(M. Petr 2000)

VLT-FORS optical

VLT-ISAAC infrared (JHK)

Sydney Zoo

Lada 2002

Why antarctica for infrared studies it s cold
Why Antarctica for infrared studies? ObservationsIt’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

Sydney Zoo

Greatly reduced infrared sky brightness

H Observations






Greatly Reduced Infrared Sky Brightness

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

Sydney Zoo

Phillips et al. 1999

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

2MASS 2mm


Sydney Zoo

Wide field infrared imaging surveying large areas
Wide-Field Infrared Imaging: ObservationsSurveying 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

Sydney Zoo

The antarctic infrared survey
The Antarctic Infrared Survey Observations

  • 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

Sydney Zoo

The antarctic infrared survey1
The ObservationsAntarctic 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

Sydney Zoo

Formation of planets protoplanetary disks
Formation of Planets: ObservationsProtoplanetary Disks

  • Dusty disks have temperatures perfectly matched to the thermal infrared.

  • Their presence can be inferred from excess IR emission.

Sydney Zoo

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

L-band SPIREX data



Disks manifest themselves as excess L-band

emission (Kenyon & Gomez 2001)

Sydney Zoo

L and t dwarfs
L and T Dwarfs Observations

  • Coolest stars and brown dwarfs are called “L and T dwarfs”

  • Boundary between stars and brown dwarfs is 0.07 solar masses

Sydney Zoo

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

Cooler (lower mass)


Brown dwarfs

Sydney Zoo

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

Sydney Zoo

Star forming regions 30 doradus
Star-forming Regions: 30 Doradus detect?

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!

Sydney Zoo

Airs scientific goal
AIRS Scientific Goal detect?

  • 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

Sydney Zoo

Telescope design
Telescope Design detect?

  • 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

Sydney Zoo

Aircam camera design
AIRCAM Camera Design detect?



Sydney Zoo

Camera detect?

  • 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

Sydney Zoo

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

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

Sydney Zoo

Prototype spirex abu
Prototype: SPIREX/Abu detect?

  • Every aspect of AIRS has been successfully demonstrated by SPIREX/Abu:

    • Telescope

    • Camera

    • Community Access

    • Data pipeline

  • AIRS requires no new technology

Sydney Zoo

The south pole site
The South Pole Site detect?

  • 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.

Sydney Zoo

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

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

  • Sydney Zoo

    Another advantage of dome c land transport
    Another Advantage of Dome C: detect?Land Transport

    • Large pieces can be hauled in

    • Greatly reduces assembly time on ice

    Sydney Zoo

    Schedule detect?

    • 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

    Sydney Zoo

    James jackson
    Plan detect?

    • 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

    Sydney Zoo

    James jackson
    AIRS detect?

    • 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

    Sydney Zoo

    Summary detect?

    • 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.

    Sydney Zoo