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)

2/33

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

3/33

Bigger is Better!

JWST’s mirror is almost 3 times larger than Hubble’s 4/33

JWST Full Scale Model at NASA

5/33

Where to find JWST

6/33

A gold plated telescope!

7/297/33

A gold plated telescope!

8/33

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.

10/33

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.

11/33

The Universe is Expanding

12/33

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

13/33

Scale factor (1+z) tells us how much the wavelengths have been stretched.

Image Credit: Wikipedia/Aleš Tošovský

Formation of the First Galaxies

14/33

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

15/33

Fields of View of JWST Instruments

16/33

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

17/33

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

18/33

View of NIRCam’s Optics

19/33

NIRCam with Enclosures

20/33

NIRCam Filter Wheel

21/33

Assembled Modules

22/33

NIRCam: The Near Infrared Camera

23/33

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

24/33

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

25/33

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.

27/33

The assembly of galaxies Where and when did the Hubble Sequence form? How did galaxies like the Milky Way take shape?

28/33

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

29/33

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

30/33

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

31/33

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

32/33

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

33/33