Hubble Science Briefing Delivering JWST Science from Exoplanets
Hubble Science Briefing Delivering JWST Science, from Exoplanets to First Light: The Near-Infra. Red Imager and Slitless Spectrograph (NIRISS) March 6, 2014 Alex Fullerton (STSc. I) 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 3. ) Solve the mysteries of star formation and birth of protoplanetary systems 2. ) Determine how galaxies evolve from the early Universe to the present day 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 Optical Bench NIRISS 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 SOSS Getting very precise spectra of bright objects, for example to extract information about exoplanets. Aperture Masking Interferometry Imaging AMI Imaging 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 NIRISS Observing Mode 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 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 from thermal Measure size of planet. Precision needed: 1 part incirculation 100 phase curves See starlight transmitted through planet atmosphere. Precision needed: 1 part in 10, 000 15
Single Object Slitless Spectroscopy [SOSS] 16
GR 700 XD Grism weak cylindrical surface (lens) Weak Lens + Prism Side Weird Stuff! Prism: Zn. S (Zinc Sulfide) Grism: Zn. Se (Zinc Selenide) Grism Side 17
Real Data vs Simulations ISIM CV 1 (October 2013) 2. 5 microns 0. 5 microns Simulation (U. de Montréal) 2 nd Order 1 st Order 18
Spectroscopy of the “Water World” GJ 1214 b 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 J 0647+7015: Image in NIRISS F 200 W HST Image: Composite of ACS and WFC 3 exposures. Credit: NASA, ESA, M. Postman and D. Coe (STSc. I), and the CLASH Team. Simulation of the CLASH field through the NIRISS F 200 W filter by Chris Willott (NRC) and Van Dixon (STSc. I). 23
MACS J 0647+7015: GR 150 R Grism F 200 W GR 150 R Disperses Along Rows Simulations by Willott and Dixon 24
MACS J 0647+7015: GR 150 C Grism F 200 W GR 150 C Disperses Along Columns Simulations by Willott and Dixon 25
Extract Spectra From Both Orientations And Identify Spectral Features Filter Image GR 150 R GR 150 C Hydrogen Emission at redshift of 9. 25 Brightness GR 150 R GR 150 C Simulations by Willott and Dixon 26
2013 March: Integration 27
Hanging Out 28
What’s Happening Now? NIRCam is being worked on back here. ISIM Structure 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 CV 1 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
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