science with the near-infrared camera on the james webb space telescope hubble science briefing...
TRANSCRIPT
Science with the Near-Infrared Camera on the James Webb Space Telescope
Hubble Science Briefing
Looking Forward to our Deepest View of the Universe:
December 4, 2014
Gerard Kriss
Space Telescope Science Institute
The James Webb Space Telescope (JWST)
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Who is James E. Webb?
1906 - 1992 NASA’s Second Administrator Led the Apollo effort Implemented the space
science program within NASA Began proposal efforts for
large space based telescopes
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Bigger is Better!
JWST’s mirror is almost 3 times larger than Hubble’s 4/33
JWST Full Scale Model at NASA
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Where to find JWST
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A gold plated telescope!
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A gold plated telescope!
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What is Infrared Light?
9/33Image Credit: Lawrence Berkeley Lab Microworlds Projecthttp://www2.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html
Infrared Light
• Infrared light can see through some materials that visible light can’t.
• With an infrared camera, we can see the heat from the man’s arm and hand and “see” through the black bag.
• Infrared light can also see through thick smoke and fog.
• We need infrared light to see the stars in the most distant galaxies.
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Infrared Light
• Infrared light can see through some materials that visible light can’t
• With an infrared camera, we can see the heat from the man’s arm and hand and “see” through the black bag.
• Infrared light can also see through thick smoke and fog.
• We need infrared light to see the stars in the most distant galaxies.
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The Universe is Expanding
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Image Credit: GSFC HEASARC “Imagine the Universe”http://imagine.gsfc.nasa.gov/features/yba/M31-velocity/hubble-more.html
Image Credit: Science Blogs, Ethan Siegelhttp://scienceblogs.com/startswithabang/2008/02/07/ the-cosmic-microwave-background-not-always/
Redshifts and Blueshifts
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Scale factor (1+z) tells us how much the wavelengths have been stretched.
Image Credit: Wikipedia/Aleš Tošovský
Formation of the First Galaxies
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Z=30
Z=7
Z=15
First Galaxies Form
Visible light for these galaxiesis redshifted to infrared wavelengths.
Image Credit: Evolution, a Scientific American Reader 2006, University of Chicago Press
Four Science InstrumentsMIRI
NIRISS
NIRCam
NIRSpec
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Fields of View of JWST Instruments
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0
-2
-4
2
4
0-2-4-6-8 2 4 6 8Horizontal Field Position (arcmin)
Vert
ical Fi
eld
Posi
tion
(arc
min
)
NIRSpec
NIRCam
MIRI
NIRISS FGS
NIRCam has Two Imagers in Two Modules
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Long wavelength channelShort wavelength channel
Mo
du
le A
Mo
du
le B
Long wavelength channelShort wavelength channel
Mo
du
le A
Mo
du
le B
Long wavelength channelShort wavelength channel
Mo
du
le A
Mo
du
le B
Long wavelength channelShort wavelength channel
Mo
du
le A
Mo
du
le B
2.2 arcmin
2.2 arcmin
2.2 arcmin
Two adjacent fields of view (2.2 arcminute)2 Both fields in SW and LW bands Two back-to-back modules
NIRCam Optical Layout
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View of NIRCam’s Optics
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NIRCam with Enclosures
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NIRCam Filter Wheel
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Assembled Modules
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NIRCam: The Near Infrared Camera
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Coronagraphic masks:
2 channels in each module:
Short Wavelength(0.6-2.3 m)
Long Wavelength(2.4-5.0 m)
HgCdTe FPA Format(22) (2040 2040)
HgCdTe FPA Format1 (2040 2040)
0.032 arcsec/pixel 0.065 arcsec/pixel
FOV= 2.212.21 arcmin2
FOV= 2.212.21 arcmin2
2 functionally identical (mirror image) modules
Filters provide (W R=4; M R=10; N R=100) LW Grisms provide R~3000
5” gap between SW SCAs
40” gap between A & B
Sensitivity (S/N=10, R=4, in 104 s):
1.1 m: 10.4 nJy 2.0 m: 12.1 nJy 4.4 m: 24.5 nJy
0.1
1
10
100
1000
0.5 1.5 2.5 3.5 4.5
m)
nJy
Ground (Keck/VLT) Space (HST or SPITZER) NIRCam z=5.0 z=10.1
5-sigma, 50,000 secs
NIRCam Sensitivity Comparison
Wavelength (Microns)Galaxy models:
HST
SSTGround
JWST NIRCam
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Birth of stars and protoplanetary systems
End of the dark ages: first light and reionization
Planetary systems and the origins of life
The assembly of galaxies
JWST has Four Science Goals
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Galaxies Form as Gas Clouds Collapse in the Early Universe
26/33Image Credit: Volker Springel, et al. 2004
After the Big Bang, gas in the universe is smoothly distributed, with slight irregularities that we can see in the Cosmic Background Radiation.
Gravity causes the densest filaments and points to collapse.
These dense knots form the first stars and galaxies.
Image Credit: NASA / WMAP: http://map.gsfc.nasa.gov/media/080997/index.html)
End of the dark ages:first light and reionization
What are the first galaxies? What objects reionized the gas between the galaxies?
Key JWST Observations:• Ultra-Deep Near InfraRed survey
(NIRCam, NIRISS) • Spectroscopic Near-IR & Mid-IR
confirmation. (NIRCam & NIRISS Grisms, NIRSpec, MIRI)
o The red circles show the locations of faint, red distant galaxies.
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The assembly of galaxies Where and when did the Hubble Sequence form? How did galaxies like the Milky Way take shape?
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The Eagle Nebula as seen by HST
Birth of stars and protoplanetary systems
How do interstellar clouds collapse to form stars?
How do gaseous disks form around stars?
How do planets condense out of the gaseous disks?
• Imaging of molecular clouds• Survey “elephant trunks”• Survey star-forming clusters
Deeply embedded protostar
Agglomeration & planetesimals Mature planetary system
Circumstellar disk
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The Eagle Nebulaas seen in the infrared
Birth of stars and protoplanetary systems
How do interstellar clouds collapse to form stars?
How do gaseous disks form around stars?
How do planets condense out of the gaseous disks?
• Imaging of molecular clouds• Survey “elephant trunks”• Survey star-forming clusters
Deeply embedded protostar
Agglomeration & planetesimals Mature planetary system
Circumstellar disk
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Planetary systems and the origins of life
How do planets form? How are circumstellar disks
like our Solar System? How are habitable zones
established?
• NIRCam will use coronagraphy to image protoplanetary disks and extra-solar giant planets
• NIRCam will obtain images and spectra of circumstellar disks, comets, moons, and Kuiper Belt Objects in the outer Solar System
Titan
Spitzer imageSimulated JWST image:Fomalhaut at 24 microns
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NIRCam’s Wavefront Sensing Role
NIRCam provides the imaging data needed for wavefront sensing.
Dispersed Hartmann Sensors at 0° and 60° orientations permit phasing of adjacent mirror elements.
Coarse phasing w/DHS
After coarse phasing Fully aligned
Fine phasing
First Light
After segment capture
DHS at pupil Spectra recorded by NIRCam
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On-line Resources
STScI JWST Home Pagehttp://www.stsci.edu/jwst/
JWST Primerhttp://www.stsci.edu/jwst/doc-archive/handbooks
STScI NIRCam Pagehttp://www.stsci.edu/jwst/instruments/nircam
University of Arizona NIRCam Pagehttp://ircamera.as.arizona.edu/nircam/
University of Arizona NIRCam Girl Scouts Pagehttp://zeus.as.arizona.edu/~dmccarthy/GSUSA/index.htm
NASA NIRCam Pagehttp://www.jwst.nasa.gov/nircam.html
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