Hubble Science Briefing Delivering JWST Science, from Exoplanets to First Light: The Near-InfraRed Imager and Slitless Spectrograph (NIRISS) March 6, 2014 Alex Fullerton (STScI) 1
Agenda for Today The Science Themes of JWST What is NIRISS and How Can It Help? Hardware Observing Modes What s happening next? Your Questions! 2
James Webb Space Telescope Maryland Science Center, Baltimore s Inner Harbor (2011 October 23) 3
James Webb Space Telescope 4
The Frontiers of Knowledge: Science Themes of JWST 1.) Seek the first stars and galaxies that formed in the early Universe 2.) 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 5
JWST: Four Instruments NIRCam Near Infrared Camera NIRSpec Near Infrared Spectrograph MIRI Mid-Infrared Instrument NIRISS 6
What s in a Name? 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 = 1000 th of a millimeter. An average human hair is about 100 microns thick. Recall: The Discovery of Infrared Radiation Sir William Herschel s Experiment 1800 Feb. 11 From: Infrared Beyond the Visible http://webbtelescope.org/webb_telescope/science_on_the_edge/beyond_the_visible/ 7
Slitless Spectroscopy Spectrographs 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. Objective Prism Spectroscopy For example: A technological marvel developed for NIRSpec is the Multi-Shutter Array (MSA), which allows many slits to be configured on the fly. 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. 8
FGS / NIRISS Fine Guidance Sensor (FGS) The camera to acquire targets and guide on them during observations. Used for purely functional purposes. Supplied by CSA. Prime Contractor: COM DEV International NIRISS Optical Bench A science instrument. Supplied by CSA. Prime Contractor: COM DEV International Principal Investigator: René Doyon, Université de Montréal 9
Schematic: Optical Layout Image from Telescope 10
Enabling Elements Pupil Wheel Filter Wheel 11
Enabling Elements 12
NIRISS Observing Modes Name Acronym* What It s Good For Wide-Field Slitless Spectroscopy WFSS Getting spectra of everything in the field of view** Single Object Slitless Spectroscopy Aperture Masking Interferometry Imaging SOSS AMI Imaging Getting very precise spectra of bright objects, for example to extract information about exoplanets. Finding and measuring the properties of faint things that are very close to bright things; for example exoplanets. Taking 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 1/10 th the area of the full moon. 13
JWST Science Themes vs. NIRISS Capabilities 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 14
Exoplanet Transit and Eclipse Science Seager & Deming (2010, ARAA, 48, 631) Precision needed: 1 part in 1,000 Transit Learn about atmospheric Measure size of planet. circulation from thermal Precision needed: 1 part in 100 phase curves See starlight transmitted through planet atmosphere. Precision needed: 1 part in 10,000 15
Single Object Slitless Spectroscopy [SOSS] 16
GR700XD Grism weak cylindrical surface (lens) Weird Stuff! Prism: ZnS (Zinc Sulfide) Grism: ZnSe (Zinc Selenide) Weak Lens + Prism Side Grism Side 17
Real Data vs Simulations ISIM CV1 (October 2013) 2.5 microns 0.5 microns Simulation (U. de Montréal) 2 nd Order 1 st Order 18
Spectroscopy of the Water World GJ1214b Input spectrum Simulated NIRISS spectrum 19
JWST: First Light, First Galaxies JWST will Study the First Galaxies Simulation (U. de Montréal) 20
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. 21
Wide-Field Slitless Spectroscopy [WFSS] 22
MACS J0647+7015: Image in NIRISS F200W 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). 23
MACS J0647+7015: GR150R Grism F200W GR150R Disperses Along Rows Simulations by Willott and Dixon 24
MACS J0647+7015: GR150C Grism F200W GR150C Disperses Along Columns Simulations by Willott and Dixon 25
Brightness Extract Spectra From Both Orientations And Identify Spectral Features Filter Image GR150R GR150C Hydrogen Emission at redshift of 9.25 GR150R GR150C Simulations by Willott and Dixon 26
2013 March: Integration 27
Hanging Out 28
What s Happening Now? ISIM Structure NIRCam is being worked on back here. NIRSpec MIRI Stand for NIRCam http://www.jwst.nasa.gov/webcam.html 29
What s Happening Next? Space Environment Simulator Cryogenic Vacuum (CV) Testing at Goddard One down, two to go ISIM being lowered into the SES chamber before CV1 30
Then: Testing at Johnson 31
Then: the Fun Really Begins! 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 you Amazing results from NIRISS, NIRCam, NIRSpec, and MIRI! Thanks for your continued interest and support! 32
For More Information 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 Center 2012 July 30 33