NIRCam Overview - STScI · NIRCam Overview l NIRCam is the near ... (ETH) Peter Martin (UToronto)...

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INS Division JWST Training Series NIRCam – Stefano Casertano 10/31/2002

NIRCam Overview

l NIRCam is the near-infrared imager on JWST, which covers the wavelength rangefrom 0.6 to 5 mm, and figures prominently in most planned science programs forJWST

l The instrument was selected in the spring. The winning concept is led by MarciaRieke (University of Arizona), and will be built by Lockheed. The Canadian SpaceAgency is also involved.

l The University of Arizona NIRCam can image a 2.3’x4.6’ FOV in two broad bandfilters simultaneously via dichroics, with critical sampling at 2 and 4 mm

l NIRCam includs 7 broad-band filters with R=4 and 8 medium-band filters thatcover features of ices and T dwarfs

l NIRCam also has two special features: two tunable filters with R~100, andcoronographic apertures in all instruments

l NIRCam is currently undergoing a Phase A study (due February 2003) to establishthe detailed design

l General information can be found at http://ircamera.as.arizona.edu/nircam

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NIRCam Features at a Glance

Choice of coronagraphic spots andpupils in all instrument sections

Coronagraphy

Imaging: 0.034”/pixel l<2.5mm

0.068”/pixel l<2.5mm

R = 100: 0.068”/pixel

Spatial Resolution

Imaging: 2.3’ x 4.6’ at twowavelengths simultaneously

R=100 Imaging: Two 2.3’x2.3’ fields(one l < 2.5mm, one l > 2.5 mm)

Fields of View

Selection of R~4 and R~10 discretefilters, R~100 using 2 tunable filters

Spectral Resolutions

0.6-5.0mmWavelength Range

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Instrument Overview - 1

Approximate size andplacement of NIRCamwithin the ISIM

The camera is verycompact and consists oftwo blocks

The left has the short andlong-wavelength tunablefilters

The right has the normalimaging elements

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Instrument Overview - 2

One of two NIRCam normalimaging modules

The dichroic splits the lightat 2.3 mm into short andlong wavelength components,imaged with different fratios

Each detector covers2.3’x2.3’. Pixel sizes areoptimized for Nyquistsampling at 2 and 4 mm; theshort l detector is 4k, thelong l is 2k

Filter wheels include pupilsfor wavefront sensing

The tunable filter modulesare similar, without dichroicor wavefront sensing

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Focal Plane Arrangement

Schematic arrangement ofthe focal plane covered byNIRCam, as seen from thesky

Top: the two tunable filters,each covering 2.3’x2.3’

Bottom: the two fieldsimaged in broad band.

Both fields on the bottomare imaged simultaneously inshort and long wavelength (<and > 2.4 mm), with aninstantaneous field of viewof 2.3’x4.6’, or 10 squarearcmin, in each

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NIRCam Detectors

The focal plane arrangement ofNIRCam, as seen from thedetectors

The detectors (Figer presentation)will be sensitive in the range 0.7to 5 mm. NIRCam uses 12 2k x2k arrays, for a total of 48Mpixel

Detectors and focal-planeelectronics will be procured byGSFC

Note that the short-wave andlong-wave arrays cover the sameregion of sky

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Filter selection

NIRC_X0052

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Performance of adopted filter set

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0.00 0.05 0.10 0.15 0.20

|Zin-Zout|/(1+Zin)

1<Z<2 2<Z<5 5<Z<10NIRC_X0052

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1<Z<2 2<Z<5 5<Z<10

NIRC_X0054

CO ice

H2O ice

CO2 ice

N2 ice

CH4 ice

NH3 ice

Pholus

WR106

PAH

EI 18

L-dwarf

T-dwarf

W33A0

1

2

3

4

5

Sig

nal (

linea

r un

its)

1.0 1.25 1.6 2.0 2.5 3.2 4.0 5.0Wavelength (µm)

NIRCam’s filters were chosen for• photometric redshift estimation• ability to distinguish ices and other solidstate features• photometric properties -- ability tocalibrate into physical units without detailedknowledge of input source spectrum

(M. Rieke / SWG meeting / 9/24/2002)

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Complete Filter and Pupil List

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NIRCam Tunable Filters andCoronographs

l Tunable filter modules

– The two tunable filter modules will cover 1.2 to 2.3 and 2.5 to 4.5 mmrespectively.

– They have a scale of 0.068”/pixel (2.3’ x 2.3’) and a spectral resolution of1%.

– Each wavelength to be observed requires a separate exposure, but thefull FOB is observed at the same time.

– The two modules cover different areas of the sky.

l Coronographic capabilities

– All NIRCam modules have coronographic spots in the telescope focal plane

– The pupil wheels include coronographic masks

– The coronographic spots in the tunable filter modules allow low-resolutionspectra to be obtained for faint objects near bright stars (e.g., planets)

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The NIRCam Team

Science Team:

Marcia Rieke(UAz) Stefi Baum(STScI) Chas Beichman(JPL)David Crampton (HIA/DAO) René Doyon (UMontreal) Daniel Eisenstein (UAz)Tom Greene (NASA Ames) Klaus Hodapp (UHawaii) Scott Horner (LMATC)Doug Johnstone (HIA/DAO) Simon Lilly (ETH) Peter Martin (UToronto)Don McCarthy (UAz) Michael Meyer (UAz) George Rieke (UAz)Tom Roellig (NASA Ames) John Stauffer (SSC) John Trauger(JPL) Erick Young (UAz)

Bold = Science Theme Leader Blue: EPO Leader

Corporate Partners:

Lockheed Martin Advanced Technology Center, Palo Alto, California

EMS Technologies, Ottawa, Ontario

COM DEV, Cambridge, Ontario

Goddard Instrument Manager: Doug Campbell

STScI Instrument Scientist: Stefano Casertano

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The NIRCam Team ScienceProgram and the DRM

* Although NIRCam observations were not specified by the ASWG forDRM#7 and DRM#10, they will make substantial contributions.

1. Formation and evol. of galaxies I. Imaging 3. Map dark matter at high z 5. Cosmology with high z SN 7. Physics of star form: youngest protostars* 8. WD LF in globular clusters 9. BDs and Jovian planets 10. Gas, dust in young star disks* 11. Evolution of cosmic SN rates 12. Origin of sub-stellar objects 13. Formation and evolution of cluster galaxies The first galaxies and reionization Period of galaxy assembly Structure of pre-stellar cores Cloud fragmentation and the IMF Emerging from the cocoon Kuiper belt imaging Debris disks Massive planets

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NIRCam Programs byNumber and Title

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NIRCam Team Science ProgramOur camera design is driven by the requirements derived from theDesign Reference Mission and our team science needs.

Team Science Program:

NIRCAM_X000

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NIRCam

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NIRCAM_X000

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NIRCam

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young solar system Kuiper Belt

Planets

When Galaxies Were Young:Discovering the First Galaxies, Reionization,Period of Galaxy Assembly

Making of a Star: Testing the ‘StandardModel: Physics of the IMF, Structure of Pre-stellar Cores, Emerging from the Dust Cocoon

Debris Disks and Planetary Systems:Disks from Birth to Maturity, Survey of KBOs,Planets Around Nearby Stars


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When Galaxies were Young


Ha Survey

Broadband Survey

2.3’

2.3’

2.3’ Broadband Survey

2.3’

3 Line LyaSurvey

Current observations have pusheddetections of QSOs to z~6. The cosmicbackground radiation was emitted atz~1000. The interval between these z’shas been dubbed the “Dark Ages”. It isNGST’s job to discover

• the first light emitting objects• the epoch when H became reionized• how galaxies were assembled and howthey developed their characteristic shapeswe recognize today

Team will use 50,000 sec exposures perfilter on two 4.6’x4.6’ regions of sky toprobe the “Dark Ages”.

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NIRCam Science - Galaxies

NIRCam’s primary goal -JWST’s primary goal - isthe detection of “firstlight” objects

Requires:- Deep imaging, large area- Photo-z- Spectroscopy follow-up

Ancillary goals:- When did H reionize?- When did galaxies form?- How did they become

like today’s?Deep images are good…

Simulation by Stockmanand Im - 2’x2’ field

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Science Program: Star Formation

NIRC_X0046

NIRC_X0044

The broad outline of star formation isreasonably well understood as the collapseof a cloud. This occurs quickly and in heavilyobscured environments. But what controlsthe initial mass function? How do cloudcores collapse to form protostars? Doesmass loss via jets play a crucial role inregulating star formation?

Team will combine surveys of star formingregions and dense clouds with detailedobservation of selected protostars and disksto address these questions.


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Reconstructing a Spectrumwith NIRCam

NIRC_X0050

Debris disk like Vega’s at 60pcwith star suppressed by thecoronagraph. Vertical arrow = 1”

NIRSpec spectrumincluding the disk.

NIRSpec spectrumwithout the disk.

NIRCam builds up a spectrum by taking aseries of images. Consequently spectralinformation can be obtained withoutknowing positions ahead of time or insituations where high dynamic rangescenes need to be observed.

NIRC_0113

DRM Capability NIRCam NIRSpec

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Imaging Photometric redshifts Other broadband (phys. photometry)

Intermediate bandHigh dynamic range (coronagraphy)

Low Resolution SpectroscopySingle objectMultiobjectImagingHigh dynamic range, coronagraphic

Medium Resolution SpectoscopySingle objectMultiobject


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Science Program: Disks and Planets

NIRC_X0051

planet

starresidual

NIRC_X0049NIRC_X0049

Many debris disks and planets aroundother stars have been discovered recently.However, these objects have not beencharacterized in any detail. How do debrisdisks form and evolve? How are theyrelated to the Kuiper Belt in the SolarSystem? How many planets orbit nearbystars? What are the characteristics ofthese planets?

Team will use the coronagraph to observethe reflected light from disks. A survey forplanets around nearby stars will be donewith more detailed study of the brighterplanets. A sample of Kuiper Belt objectswill be surveyed to define their surfaceproperties for comparison with debrisdisks.(M. Rieke / SWG meeting / 9/24/2002)

NIRCam Overview - STScI · NIRCam Overview l NIRCam is the near ... (ETH) Peter Martin (UToronto)...

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