Transcript ppt - Stratospheric Observatory for Infrared Astronomy

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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
R. D. Gehrz
Outline
• SOFIA Science
• Description of the Observatory and Project Status
• Schedule
• Summary
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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Science
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Key Science Topics Related to Origins
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•
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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
Astronomy and Astrophysics Advisory Committee, October 12, 2007
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SOFIA and the Chemical Evolution of the Universe
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The Advantages of SOFIA
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•
Above 99% of the water vapor
•
Transmission at 14 km >80%
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
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A near-space observatory that
comes home after every flight
Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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
SOFIA’s bands
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Serabyn and Weisstein 1995
Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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Clues to the evolution of galaxies: starbursts triggered by collisions and star
formation in low-metallicity environments
NASA/JPL-Caltech/Z. Wang
Antennae Galaxies
IRAC @ 8 mm (red; 160s, 4’ x 4’)
HAWC Beam Sizes
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NASA/JPL-Caltech/V. Gorjian
Henize 206- LMC high mass star formation
MIPS @ 24 mm (80s, 20’ x 20’)
HAWC Fields of view (Current 12x32 array at
53, 89, 155, 216 mm; Circle is total optical
FOV)
Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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 (T<50K) 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]
HI
[Ne II]
[Ne V] [Ne III]
[O IV]
[Ne III]
[Ne V]
IRS Short-High
IRS Long-High
IRS Short and Long-High Spectra: Abundances and Kinematics
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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SOFIA’s 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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10 7
Planetary Atmospheres
Chemistry of the cold ISM
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Dynamics of collapsing protostars
Comet Molecules
Spectral resolution
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Dynamics of the Galactic Center
Velocity structure and gas composition in
disks and outflows of YSOs
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PAH & organic molecules
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Composition/dynamics/physics of the
ISM in external galaxies
Nuclear synthesis in supernovae in nearby galaxies
Composition of interstellar grains
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Debris Disk Structure
10 1
KBOs, Planet Transits
Luminosity and Morphology of Star Formation Galactic and
Extra-Galactic Regions
10 0
1
10
100
1000
Wavelength [µm]
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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SOFIA Performance: Spectral Resolution of the
First Generation Science Instruments
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Spectral resolution
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10
7
10
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10
5
10
4
10
3
GREAT
CASIMIR
EXES
FLITECAM
FORCAST
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2
10
1
HIPO
FORCAST
SPITZER IRS
FIFI LS
SAFIRE
MIPS HAWC
IRAC
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18
0
1
10
Wavelength [µm]
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1000
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SPITZER
SAFIR
0.3
Herschel
Wavelength (µm)
1000
SOFIA
?
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Frequency (THz)
Infrared Space Observatories
JWST
10
30
1
2005
Ground-based
Observatories
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2010
2015
2020
2025
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 mm)
• Operating altitude
– 39,000 to 45,000 feet (12 to 14 km)
– Above > 99% of obscuring water vapor
• Joint Program between the US (80%) and Germany (20%)
• First Light Science 2009
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–
–
–
–
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20 year design lifetime
Science Ops at NASA-Ames and Flight Ops at NASA-Dryden
Deployments to the Southern Hemisphere and elsewhere
>120 8-10 hour flights per year
Built on NASA Lear/Kuiper Airborne Observatory Heritage
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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Nasmyth: Optical Layout
M2
Pressure bulkhead
Spherical Hydraulic Bearing
Nasmyth tube
Focal Plane
M3-1
M3-2
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Primary Mirror M1
Focal Plane
Astronomy and Astrophysics Advisory Committee, October 12, 2007
Imager
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The Un-Aluminized Primary Mirror Installed
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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Status
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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
• Door Drive Delivered
Winter ’07
• Open Door Flights at DFRC
Fall ’08
• First Science
• Next Instrument call
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Occurred April ’07
‘09
‘10
Astronomy and Astrophysics Advisory Committee, October 12, 2007
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US General Observer Opportunities
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First call for science proposals in ’09
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Future calls every 12 months
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First General Observers 2010
• Expect ~ 20 General Observer science flights
• Shared risk with Instrument PI’s
• Open Observatory with Facility Instruments
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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Summary
• SOFIA has unique spectral and temporal coverage
– Unique high-resolution spectroscopy: 28 < l < 150 μm
– (l/10 μm) arc-sec image quality, unique for 30 < l < ~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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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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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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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SOFIA’s 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
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Major Science Programs for SOFIA:
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–
–
–
–
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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 Cost per
Hours
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
• SOFIA’s total operating costs are comparable to those of
the other Great Observatories
• SOFIA has fewer operating hours (it’s an airplane)
•SOFIA’s costs include servicing missions with new focal
plane instruments every few years
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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Courtesy of Gary Melnick
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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Courtesy of Gary Melnick
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Astronomy and Astrophysics Advisory Committee, October 12, 2007
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