Unveiling James Webb Space Telescope: A Next-Generation Megastructure in Space

1. The James Webb Space Telescope: Our Megastructure in Outer Space Andrew Bunker (Oxford University, JWST-NIRSpec Instrument Team)

2. NGST/JWST History • Coordinated NASA, ESA and CSA Studies since 1997 • JWST is consistent with the scientific program for a “Large Infrared-Optimized Space Telescope”, described in the report “HST and Beyond” (Dressler 1996), and • the program for the “Next Generation Space Telescope”, which was given top priority by the National Academy of Sciences survey “Astronomy and Astrophysics in the New Millennium” (McKee & Taylor, 2001).

3. NGST/JWST History • 1996:ESA invited to participate in NGST studies, 8-m • 1998:2nd NGST Conference held in Liege • Ad Hoc Science Working Group (ASWG) • 1999:Design Reference Mission completed • 2001: ESA NIRSpec and MIRI Studies initiated • 2002: NGST renamed JWST, Ariane V Launcher • 2003: Telescope reduced to 6.5-m • 2005: “Tiger team” re-scope: PSF at 1micron not science driver • 2007: Technology Ready • 2008: Start of phase C/D (construction) • 2014: Launch (Cycle 1 observations begin 2015)

4. Who Was James Webb? James E. Webb Second NASA administrator, during Apollo Edwin Hubble

5. What is JWST? • 6.55 m deployable primary • Diffraction-limited at 2 µm • Wavelength range 0.6-28 µm • Passively cooled to <50 K • Zodiacal-limited below 10 µm • Sun-Earth L2 orbit • 4 instruments • 0.6-5 µm wide field camera (NIRCam) • 1-5 µm multiobject spectrometer (NIRSpec) • 5-28 µm camera/spectrometer (MIRI) • 0.8-5 µm guider camera (FGS/TF) • 5 year lifetime, 10-11 year goal • 2014 launch

6. Goddard Space Flight CentreNorthrop GrummanOperations:STScIProject Scientist: John Mather

7. JWST Architecture Integrated Science Instrument Module (ISIM) Element Optical Telescope Element (OTE) Sunshield Spacecraft Bus Sun

8. ESA Contributions to JWST • NIRSpec • ESA Provided • Detector & MEMS Arrays from NASA • MIRI Optics Module • ESA Member State Consortium • Detector & Cooler/Cryostat from NASA • Ariane V Launcher (ECA) (closely similar to HST model…)

9. Telescope

10. Funky PSF? Image Core 2 µm PSF Wings

12. Orbit 0

13. Sky "glow" in the near-IR

14. MIRI - mid-infrared instrument 5 < λ < 27 μm Cryocooler to 7K; Broad-band imaging; 2sq arcmin R=3000 spectroscopy; also has a coronograph European Consortium, ESA & JPL (50/50).

15. NIRCAM : 1-5micron imager (U of Arizona) 10 square arcmin, two channels at once Uses Hawaii-2KRG arrays FGS-TFI (Fine Guidance Sensor & Tunable Filter Imager), Canadian Space Agency Can take 1% narrow-band images over 1.6-4.9microns, 5 square arcmin

16. JWST Imaging Sensitivity

17. NIRSpec • 3 x 3 arcmin FOV • 1-5 µm coverage • R~1000, R~100 multiplexed • >100 sources simultaneously • Configurable slit width/length • MEMS array - “build your own slitmask in space”

18. Slide from J. Gardner (NASA)

19. …scientific objectives and requirements of the James Webb Space Telescope (JWST) Project.JWST will be a large, cold, infrared-optimized space telescope designed to enable fundamental breakthroughs in our understanding of the formation and evolution of galaxies, stars, and planetary systems. 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

20. Detector Array • 2K4K FPA comprised of two 2K2Ksensor chip assemblies (SCAs) • =0.6–5.0 µm HgCdTe detectors (Rockwell) • FPA passively cooled to T=34–37 K • Key Performance Parameters: • Total noise =6 electrons rms per t=1000 seconds exposure) • QE = >80% • NIRSpec is detector background limited in nearly all modes (!) • Non-stop (“up the ramp”) read and telemetry • 12 s frame time, 1 frame downlink each 50 s

21. The European JWST Family NIRSpec:Arribas, Santiago (Madrid) Bunker, Andrew (Oxford) Charlot, Stephane (IAP) Franx, Marijn (Leiden) Jakobsen, Peter (ESA) - Chair Maiolino, Roberto (Rome) Moseley, Harvey (NASA/GSFC) Rauscher, Bernie (NASA/GSFC) Regan, Mike (STScI) Rix, Hans-Walter (MPIA) Willott, Chris; Crampton, David (HIA) SWG: Lilly, Simon (ETH) McCaugrean, Mark (ESA) Wright, Gillian (Edinburgh) MIRI: co-PI: G. Wright With a large team (Too many to list here…)

22. NIRSpec IST

23. Physical Layout

24. Micro Shutter Array Single 200 mas x 450 mas slits surrounded by 50 mas wide bars >100 objects simultaneously 4 x 384 x 185 Shutters 9 Square Arcmin of MSA Area

26. MSA Contrast Simulation Select Objects (Detail) HDF-S Field

27. MSA Contrast Simulation Configure Slits (Detail) Spoilers! Undispersed image with MSA mask in place

28. MSA Contrast Simulation Configure Slits (larger view) Image Mode with MEMS mask in place

29. MSA Contrast Simulation Insert Grating and Integrate

30. Why are we bothering? Want to find the sources which reionized the Universe, and chart the history of galaxy (mass) assembly & star formation Lyman-alpha (if it emerges at all pre-Gunn Peterson) then it will be a good way to find galaxies, but the flux does not tell us the star formation rate (but EW might provide clues to the IMF). Pop III??? Looking at longer wavelengths for other diagnositc lines (also get reddening, metallicity) Couple with NIRCAM SEDs Brightest sources: some hope of velocity dispersions Want overall luminosity functions, EW distributions