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Hubble Science Briefing Delivering JWST Science, from Exoplanets to First Light: The N ear- I nfra R ed I mager and S litless S pectrograph (NIRISS) March 6, 2014 Alex Fullerton (STScI). Agenda for Today. The Science Themes of JWST What is NIRISS and How Can It Help? Hardware - PowerPoint PPT Presentation
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Hubble Science Briefing
Delivering JWST Science, from Exoplanets to First Light:
The Near-InfraRed Imager and Slitless Spectrograph (NIRISS)
March 6, 2014Alex Fullerton (STScI)
1
Agenda for Today
The Science Themes of JWST
What is NIRISS and How Can It Help?
HardwareObserving Modes
What’s happening next ?
Your Questions!
2
James Webb Space Telescope
3Maryland Science Center, Baltimore’s Inner Harbor (2011 October 23)
James Webb Space Telescope
4
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
8
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
9
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
14
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 SideWeak Lens + Prism Side
Real Data vs Simulations
18
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
20
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.
2121
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
24
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
26Simulations by Willott and Dixon
Filter
Bri
gh
tne
ss
GR150RGR150C
Hydrogen Emissionat redshift of 9.25
Image GR150R GR150C
2013 March: Integration
27
Hanging Out
28
What’s Happening Now?
29
http://www.jwst.nasa.gov/webcam.html
ISIMStructure
MIRINIRSpec
Stand for NIRCam
NIRCam is being worked on back here.
What’s Happening Next?
30
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
31
Then: the Fun Really Begins!
3232
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
33
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