Hubble Science Briefing

Delivering JWST Science, from Exoplanets to First Light:

The Near-InfraRed Imager and Slitless Spectrograph (NIRISS)

March 6, 2014Alex Fullerton (STScI)

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Agenda for Today

The Science Themes of JWST

What is NIRISS and How Can It Help?

HardwareObserving Modes

What’s happening next ?

Your Questions!

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James Webb Space Telescope

3Maryland Science Center, Baltimore’s Inner Harbor (2011 October 23)

James Webb Space Telescope

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1.) Seek the first stars and galaxies that formed in the early Universe

The Frontiers of Knowledge: Science Themes of JWST2.) Determine how galaxies evolve from the early Universe to the present day

3.) Solve the mysteries of star formation and birth of protoplanetary systems

4.) Probe the chemistry of solar systems (including our own) to constrain the building blocks of life

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JWST: Four Instruments

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NIRCamNear Infrared Camera

NIRSpecNear Infrared Spectrograph

MIRIMid-Infrared Instrument

NIRISS

What’s in a Name?

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NIRISS NIR: Near Infrared Wavelengths 0.6 to 5.0 microns*

I: Imager Normal people say “camera”

SS: Slitless Spectrograph This takes some explaining

*1 micron = 1000th of a millimeter. An average human hair is about 100 microns thick.

Recall: The Discovery of Infrared Radiation

From: “Infrared Beyond the Visible”

http://webbtelescope.org/webb_telescope/science_on_the_edge/beyond_the_visible/

Sir William Herschel’s Experiment 1800 Feb. 11

“Slitless” Spectroscopy

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An objective prism spectrogram of a region near Gamma Cygni, taken October 16 – 17, 1950 with the 24-inch Schmidt telescope of the Warner and Swasey Observatory. The exposure was 4 minutes on Eastman IIa-O blue-sensitive emulsion by Daniel L. Harris.

Objective Prism SpectroscopySpectrographs typically use an entrance aperture (“slit”) to improve the resolving power (especially for spectrographs on ground-based telescopes) and to limit the region of the sky that enters the instrument.

For example:A technological marvel developed for NIRSpec is the Multi-Shutter Array (MSA), which allows many slits to be configured “on the fly.”

FGS / NIRISS

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Optical Bench

Fine Guidance Sensor (FGS)

The camera to acquire targets and guide on them during observations. Used forpurely functional purposes.

Supplied by CSA. Prime Contractor: COM DEV International

NIRISS

A science instrument.

Supplied by CSA. Prime Contractor:

COM DEV InternationalPrincipal Investigator:

René Doyon, Université de Montréal

Schematic: Optical Layout

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Image from Telescope

Enabling Elements

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Pupil Wheel Filter Wheel

Enabling Elements

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NIRISS Observing Modes

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Name Acronym* What It’s Good For

Wide-Field Slitless Spectroscopy WFSSGetting spectra of everything in the field of view**

Single Object Slitless Spectroscopy SOSSGetting very precise spectra of bright objects, for example to extract information about exoplanets.

Aperture Masking Interferometry AMIFinding and measuring the properties of faint things that are very close to bright things; for example exoplanets.

Imaging ImagingTaking pictures at different wavelengths (through different filters).

* To give you a fighting chance of following me in case I slip up later and start talking in acronyms!

** The field of view of NIRISS is about 1/10th the area of the full moon.

JWST Science Themes vs. NIRISS Capabilities

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JWST Science Theme

The End of the Dark Ages: First Light and Reionization

The Assembly of Galaxies

The Birth of Stars and Protoplanetary Systems

Planetary Systems and the Origins of Life

NIRISS Observing Mode

Wide-Field Slitless Spectroscopy (WFSS)

Single Object Slitless Spectroscopy (SOSS)

Aperture Masking Interferometry (AMI)

Imaging

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Exoplanet Transit and Eclipse Science

Learn about atmosphericcirculation from thermalphase curves

Transit

Seager & Deming (2010, ARAA, 48, 631)

Measure size of planet. Precision needed: 1 part in 100

See starlight transmittedthrough planet atmosphere. Precision needed: 1 part in 10,000

Precision needed: 1 part in 1,000

Single Object Slitless Spectroscopy [SOSS]

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GR700XD Grism

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weak cylindrical

surface (lens)

Weird Stuff!Prism: ZnS (Zinc Sulfide)Grism: ZnSe (Zinc Selenide)

Grism SidePrism Side

Real Data vs Simulations

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ISIM CV1 (October 2013)

Simulation (U. de Montréal)

0.5 microns2.5 microns

2nd Order 1st Order

Spectroscopy of the “Water World” GJ1214b

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Input spectrum

Simulated NIRISS spectrum

JWST: First Light, First Galaxies

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Simulation (U. de Montréal)

JWST will Study the First Galaxies

The First Galaxies

HST can already see galaxies formed within 500 Myr of the Big Bang(redshift, z = 11).

But neither Hubble nor JWST imaging will be able to measure the star formation rate or chemical evolution of these early galaxies.

Instead: we need spectroscopy to detect spectral lines of hydrogen and oxygen to measure the detailed properties of the very first galaxies assembling from the products of the first stars, and to confirm their redshifts.

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Wide-Field Slitless Spectroscopy [WFSS]

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MACS J0647+7015: Image in NIRISS F200W

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HST Image: Composite of ACS and WFC3 exposures.

Credit: NASA, ESA, M. Postman and D. Coe (STScI), and the CLASH Team.

Simulation of the CLASH field through the NIRISS F200W filter by Chris Willott (NRC) and Van Dixon (STScI).

MACS J0647+7015: GR150R Grism

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F200W GR150R Disperses Along Rows

Simulations by Willott and Dixon

MACS J0647+7015: GR150C Grism

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F200W GR150C Disperses Along Columns

Simulations by Willott and Dixon

Extract Spectra From Both OrientationsAnd Identify Spectral Features

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Filter

Bri

gh

tne

ss

GR150RGR150C

Hydrogen Emissionat redshift of 9.25

Image GR150R GR150C

2013 March: Integration

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Hanging Out

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What’s Happening Now?

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http://www.jwst.nasa.gov/webcam.html

ISIMStructure

MIRINIRSpec

Stand for NIRCam

NIRCam is being worked on back here.

What’s Happening Next?

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Space Environment Simulator

ISIM being lowered into the SES chamber before CV1

Cryogenic Vacuum (CV) Testing at Goddard

One down, two to go

Then: Testing at Johnson

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Then: the Fun Really Begins!

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When Where What

2014 Goddard Space Flight Center ISIM Test Campaign 2

2015 Goddard Space Flight Center ISIM Test Campaign 3

2016 Johnson Space Center Telescope + ISIM Testing

2017 Johnson Space Center Telescope + ISIM Testing

2018 French Guiana … and beyond! Launch!

2019 An astronomy center near youAmazing results from NIRISS,NIRCam, NIRSpec, and MIRI !

Thanks for your continued interest and support !

For More Information

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About NIRISS: http://www.stsci.edu/jwst/instruments/niriss(with links to the Pocket Guide and multimedia presentations)

About JWST: http://webbtelescope.org/webb_telescope/

http://www.stsci.edu/jwst/

Arrival at Goddard Space Flight Center2012 July 30