SOFIA Stratospheric Observatory for Infrared Astronomy

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SOFIA Stratospheric Observatory for Infrared
Astronomy

• R. D. Gehrz
• Lead, SOFIA Community Task Force (SCTF)
• Department of Astronomy, University of Minnesota

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Outline

• SOFIA Science
• Description of the Observatory and Project
  Status
• Schedule
• Summary

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Science
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Key Science Topics Related to Origins

• How stars form in our galaxy and other nearby
  galaxies
• Chemistry, Mineralogy, and Biology
• Solar System studies
• Targets of Opportunity, for example
• Bright Comets
• Eruptive variable stars
• Galactic and LMC/SMC classical novae
• Supernova in our galaxy or other nearby galaxies
• Eclipses and Occultations in the Solar System

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SOFIA and the Chemical Evolution of the Universe
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The Advantages of SOFIA

• Above 99 of the water vapor
• Transmission at 14 km gt80 from 1 to 800 µm
  emphasis
• on the obscured IR regions
• Instrumentation wide variety, rapidly
  interchangeable, state-of-the art
• Mobility anywhere, anytime
• Twenty year design lifetime
• A near-space observatory that comes home after
  every flight

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Unique Science Capabilities

• 8 arcmin diameter FOV allows use of very large
  detector arrays
• Image size is diffraction limited beyond 15 µm,
  making images 3 times sharper than Spitzer Space
  Telescope
• Because of large aperture and better detectors,
  sensitivity for imaging and spectroscopy will be
  similar to the space observatory ISO
• Ability to adapt to new technologies
• Ability to track temporal events

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Expectations for Improvements in Detectors
Due to increases sensitivity and the number of
pixels in large format IR detectors, the speed
of measurement has doubled every year for the
last 40 years
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Astrochemistry
SOFIA is a good observatory for
studying chemistry in space
CSO FTS Spectrum of ORION OMC1

• Most ground state molecular lines in IR or
  submillimeter
• Need high spectral resolution throughout which
  SOFIA has.
• As sensitive as CSO, but much larger wavelength
  range is accessible
• Light molecules Molecular hydrogen, HD, water,
  other hydrides in IR and submillimeter
• The fullerene, C60, has 4 IR lines in SOFIAs
  bands

Serabyn and Weisstein 1995
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Occultation astronomy with SOFIA
SOFIA will determine the properties of Dwarf
Planets in and beyond the Kuiper Belt
Pluto occultation lightcurve observed on the KAO
(1988) probes the atmosphere

• SOFIA can fly anywhere on the Earth, allowing it
  to position itself under the shadow of an
  occulting object.
• Occultation studies with SOFIA will probe the
  sizes, atmospheres, and possible satellites of
  newly discovered planet-like objects in the outer
  Solar system.
• The unique mobility of SOFIA opens up some
  hundred events per year for study compared to a
  handful for fixed observatories.

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Extrasolar Planet Transits
SOFIA will determine the properties of new
extrasolar planets by use of transits with HIPO
and FLITECAM working together
Artist concept of planetary transit and the
lightcurve of HD 209458b measured by HST
revealing the transit signature

• Today over 200 extrasolar planets are known, and
  over 15 transit their primary star
• SOFIA will fly above the scintillating component
  of the atmosphere and will provide the most
  sensitive freely pointing observatory for
  extrasolar planetary transits after HST and
  before JWST.
• SOFIA has instruments that can observe with high
  signal-to-noise the small variations in stellar
  flux due to a planet transit and
• Provide good estimates for the mass, size and
  density of the planet
• May reveal the presence of, satellites, and/or
  planetary rings

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Clues to the evolution of galaxies starbursts
triggered by collisions and star formation in
low-metallicity environments
NASA/JPL-Caltech/V. Gorjian
NASA/JPL-Caltech/Z. Wang
Henize 206- LMC high mass star formation MIPS _at_
24 mm (80s, 20 x 20) HAWC Fields of view
(Current 12x32 array at 53, 89, 155, 216 ?m
Circle is total optical FOV)
Antennae Galaxies IRAC _at_ 8 mm (red 160s, 4 x
4) HAWC Beam Sizes
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Cold Molecular Hydrogen using HD
SOFIA will study deuterium in the galaxy using
the ground state HD line at 112 microns. This
will allow determination the cold molecular
hydrogen abundance.
Atmospheric transmission around the HD line at
40,000 feet

• Deuterium in the universe is created in the Big
  Bang.
• Measuring the amount of cold HD (Tlt50K) can best
  be done with the ground state rotational line at
  112 microns.
• A GREAT high resolution spectrometer study is
  possible given ISO detection
• HD traces the cold molecular hydrogen (Bergen
  and Hollenbach).
• HD has a much lower excitation temperature and a
  dipole pole moment that almost compensates for
  the higher abundance of molecular hydrogen.
• In the future, this technique could be used much
  like the HI 21cm maps but for cold molecular gas.

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Classical Nova Explosions
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Spitzer Spectra of Nova V382 Vel
R. D. Gehrz, et al. 2005, ApJ, in preparation
PID 124
H I
Ne II
Ne V
Ne III
O IV
Ne III
Ne V
IRS Long-High
IRS Short-High
IRS Short and Long-High Spectra Abundances and
Kinematics
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SOFIAs Instrument Complement

• As an airborne mission, SOFIA supports a unique,
  expandable instrument suite
• SOFIA covers the full IR range with imagers and
  low, moderate, and high resolution spectrographs
• 4 instruments at IOC 9 instruments at FOC
• SOFIA can take full advantage of improvements in
  instrument technology
• Both Facility and PI Instruments

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SOFIA Science For the Whole Community
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SOFIA Performance Spectral Resolution of the
First Generation Science Instruments

• FORCAST

• SPITZER IRS

MIPS
IRAC
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Infrared Space Observatories
0.3
1000
?
SAFIR
Frequency (THz)
Herschel
SOFIA
3
100

JWST
SPITZER
Wavelength (µm)
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10
1
2005
2010
2015
2020
2025
Ground-based Observatories
SOFIA provides temporal continuity and wide
spectral coverage, complementing other infrared
observatories.
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Overview
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SOFIA Overview

• 2.5 m (98 inch) telescope in a modified Boeing
  747SP aircraft
• Optical to millimeter-wavelengths
• Emphasis on the obscured IR (30-300 ?m)
• Operating altitude
• 39,000 to 45,000 feet (12 to 14 km)
• Above gt 99 of obscuring water vapor
• Joint Program between the US (80) and Germany
  (20)
• First Light Science 2009
• 20 year design lifetime
• Science Ops at NASA-Ames and Flight Ops at
  NASA-Dryden
• Deployments to the Southern Hemisphere and
  elsewhere
• gt120 8-10 hour flights per year
• Built on NASA Lear/Kuiper Airborne Observatory
  Heritage

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Nasmyth Optical Layout
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The Un-Aluminized Primary Mirror Installed
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Four First Light Instruments
Working/complete HIPO instrument in Waco on
SOFIA during Aug 2004
Working/complete FLITECAM instrument at Lick in
2004/5
Working FORCAST instrument at Palomar in 2005
Successful lab demonstration of GREAT in July 2005
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Status
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SOFIA Airborne!
26 April 2007, L-3 Communications, Waco Texas
SOFIA takes to the air for its first test flight
after completion of modifications
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Early Science with SOFIA

• The aircraft has flown in April 2007 and is now
  at NASA Dryden FRC for flight certification tests
• Early Science is expected to occur in 2009
• Two instruments have been selected for Early
  Science
• - FORCAST a US 5-40 µm imager
• - GREAT a German heterodyne 60 to
  200 µm
• Spectrometer
• - Both have been tested in the lab or
  on a telescope

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Summary

• Program making progress!
• Aircraft structural modifications complete
• Telescope installed, several instruments tested
  on ground observatories
• Completed first flight and ferry flight to NASA
  Dryden
• Full envelope flight testing (closed door) has
  started.
• Several subsystems will be installed
  spring/summer 08 (Door motor drive, coated
  primary mirror)
• First science in 09
• SOFIA will be one of the primary facilities for
  far-IR and sub-millimeter astronomy for many years

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Schedule
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SOFIA Schedule (Major Milestones)

• First Re-Flight Occurred April 07
• Door Drive Delivered Winter
  07
• Open Door Flights at DFRC Fall 08
• First Science 09
• Next Instrument call 10

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US General Observer Opportunities

• First call for science proposals in 09
• Future calls every 12 months
• First General Observers 2010
• Expect 20 General Observer science flights
• Shared risk with Instrument PIs
• Open Observatory with Facility Instruments

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Next Call For New Instruments

• The next call for instruments will be at first
  Science FY10
• There will be additional calls every 3 years
• There will be one new instrument or upgrade per
  year
• Approximate funding for new instruments 8 M/yr

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Summary

• SOFIA has unique spectral and temporal coverage
• Unique high-resolution spectroscopy 28 lt l lt 150
  µm
• (l/10 µm) arc-sec image quality, unique for 30 lt
  l lt 60 µm
• Unique ability to obtain coverage of transient
  events
• Unique long operating lifetime
• SOFIA will increase its unique complement of
  capabilities in the future and will be a test-bed
  of technologies for future Far-IR missions
• State-of-the-art large format IR detector arrays
• Polarimeteric imaging and spectroscopy
• SOFIA is a hands-on Far-IR observatory
• Will train future mission scientists and
  instrumentalists
• SOFIA is on track for first science in 2009

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Appendix
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The Initial SOFIA Instrument Complement

• HIPO High-speed Imaging Photometer for
  Occultation
• FLITECAM First Light Infrared Test Experiment
  CAMera
• FORCAST Faint Object InfraRed CAmera for the
  SOFIA Telescope
• GREAT German Receiver for Astronomy at Terahetz
  Frequencies
• CASIMIR CAltech Submillimeter Interstellar
  Medium Investigations Receiver
• FIFI-LS Field Imaging Far-Infrared Line
  Spectrometer
• HAWC High-resolution Airborne Wideband Camera
• EXES Echelon-Cross -Echelle Spectrograph
• SAFIRE Submillimeter And Far InfraRed Experiment

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SOFIAs 9 First Generation Instruments
4.5-28.3
Listed in approximate order of expected
in-flight commissioning Operational (August
2004)
Uses non-commercial
detector/receiver technology
Science
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Science Objectives

• Major Science Programs for SOFIA
• Origin of stars and planetary systems
• Planetary bodies that make up our Solar System
• Life-cycle of dust and gas in galaxies
• Composition of the molecular universe
• Role of star formation and black hole activity in
  the energetics of luminous galaxies
• SOFIA has a unique suite of instruments that
  cover a wide range of wavelengths at a wide range
  of spectral resolution.
• SOFIA will be continuously upgraded with new
  instrumentation and will serve as an important
  technology development platform for future space
  missions.
• SOFIA is a highly visible icon for education and
  public outreach and will immerse educators in
  the scientific process.

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Learjet-KAO Instrumentalists and their
Contributions
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Great Observatory Operations Costs for FY 08
Observatory Ops Costs Annual Operating Hours Cost per Hour
HST 105M 4400 (50) 24K
Chandra 77M 6400 (75) 10K
Spitzer 81M 7680 (90) 12K
SOFIA 80M (est) 960/768 (Total/NASA) 104K

• CONCLUSIONS
• SOFIAs total operating costs are comparable to
  those of
• the other Great Observatories
• SOFIA has fewer operating hours (its an
  airplane)
• SOFIAs costs include servicing missions with new
  focal
• plane instruments every few years

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Courtesy of Gary Melnick
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Courtesy of Gary Melnick