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Future Giant Telescopes: Evolution in Ground-Space Synergy

Future Giant Telescopes: Evolution in Ground-Space Synergy. Richard Ellis Caltech. Astrophysics 2020: STScI, November 13 2007. NASA’s Great Observatories. ~$2.5B investment in 8-10m telescopes. Ground-Space Synergy (1990-2005). Synergistic attributes:

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Future Giant Telescopes: Evolution in Ground-Space Synergy

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  1. Future Giant Telescopes: Evolution in Ground-Space Synergy Richard Ellis Caltech Astrophysics 2020: STScI, November 13 2007

  2. NASA’s Great Observatories ~$2.5B investment in 8-10m telescopes Ground-Space Synergy (1990-2005) Synergistic attributes: Space: unique wavelengths, angular resolution, reduced IR background, all-sky Ground: photon-starved spectroscopy, panoramic fields, upgradable technologies

  3. HDF: HST GRBs: Chandra/Swift Transiting exoplanets: Spitzer Synergistic Successes • Some (of many) highlights of this partnership: • charting the 2 < z < 6 Universe: redshifts, SFRs, morphologies & masses • origin of various transients: short and long-duration GRBs, X-ray flashes • physical properties of exoplanets

  4. A Vision for Ground-Based Astronomy (1908) "It is impossible to predict the dimensions that reflectors will ultimately attain.  Atmospheric disturbances, rather than mechanical or optical difficulties, seem most likely to stand in the way.  But perhaps even these, by some process now unknown, may at last be swept aside.  If so, the astronomer will secure results far surpassing his present expectations.” George Ellery Hale, Study of Stellar Evolution, 1908 (p. 242) writing about the future of the 100 inch.

  5. A new generation of 20-42m ELTs is being designed: • Thirty Meter Telescope (www.tmt.org) - Caltech, UC, Canada + poss. Japan - 30m f/1 primary via 492  1.4m segments - $80M design underway (2004-2009) - $760M construction cost (FY2006) - major fund-raising already underway • Giant Magellan Telescope (www.gmto.org) - Carnegie, Harvard, Arizona, Texas, Australia + others - 21m f/0.7 primary via 6  8.2m segments - funds for $50M design study being raised • European ELT (www.eso.org/projects/e-elt) - 42m f/1 primary with 900+ 1.4m segments - 5 mirror design - 57M Euros design underway (2007-) TMT Era of ELTs (2016 - ) GMT E-ELT How will these AO-designed ELTs affect ground-space synergy and space astronomy?

  6. JWST vs 8m ground-based telescope (1998) • Comparison of 8m JWST and AO-fed 8m ground-based telescope: • Assuming: • point sources • AO (projected Strehl of 80% at K) • Various OH suppression/detector options • Space wins  > 2.2 m • Ground wins R>1000 1 < < 2.2m

  7. All-Sky Adaptive Optics is Here! Keck and Gemini Laser Guide Star Facilities

  8. Performance of Keck NGS AO System 50% Strehl r0 (cm) R magnitude Miranda+Uranus Neptune Titan Courtesy: Wizinowich & Keck AO team

  9. Performance of Keck LGS AO System 50% Strehl NGS LGS R magnitude r0 (cm) Keck is achieving ACS resolution in K band Courtesy: Wizinowich & Keck AO team

  10. HST Optical - Keck Near-IR Synergy • Resolved stellar populations in HII regions in IC10 • ACS: I-band • Keck AO + NIRC2: H, K’ (Strehl ~30%) • Self-calibration of AO photometry using `curve of growth’ technique (~few % accuracy) • Combined data enables direct identification of AGB stars, C stars, resolves WR complex • Analysis reveals multiple bursts of SF & accurate distance Vacca, Sheehy & Graham Ap J 662, 272 (2007)

  11. Substellar binaries Recent Keck AO Highlights 126 NGS & 30 LGS

  12. Next Generation AO on Existing 8-10m’s • NGS - seriously limited in sky coverage • LGS - modest Strehl due to `cone effect’ • Next Steps: • Multiple laser to defeat `cone effect’ LTAO • Multi-DMs widen field with uniform correction MCAO • Independent correction of multi-objects in a larger field MOAO • Improved seeing over significant fields of view GLAO • High contrast planet finders ExAO All under active development or implementation

  13. NGAO NGS LGS Keck Next Generation AO Ca Triplet H • Tomography overcomes `cone effect’ • AO-corrected, IR tip-tilt improves sky coverage • Closed-loop for 1st relay; open-loop for deployable IFUs & 2nd relay Courtesy: Wizinowich & Keck AO team

  14. ESO VLT AO Program Hawk-I • Hawk-I: 2012 + GLAO • K-band imager, 7.5’ x 7.5’ field • MUSE visible multi-IFU + GLAO: 2012 • 1' field, x 2 seeing improvement • MUSE visible narrow field IFU: 2012 • 7.5” field, ~10% Strehl at 750 nm • SPHERE:2010 • High Contrast Planet Finder MUSE

  15. Ground-Space Synergy ~ 2015 Ground-based 8-10m + NGAO: < 2.2 m • Masses/composition of KBOs and minor planets: I-band AO • Debris disks and nearby planets:high contrast JH, astrometry • Nearby AGN and Galactic center: astrometry, spatially-resolved spectra at 8500 Å • Stellar populations in nearby galaxies: imaging • High-redshift galaxies: assembly history etc multi-IFU spectroscopy in JHK JWST: 2013:> 2.2 microns • Very high z sources, stellar masses • Star-forming regions etc ALMA: 2012 • Comparable resolution to AO (~ 10-100 mas) • Complementary data on dust & cold gas

  16. Resolved Spectroscopy of High Redshift Galaxies • Major driver for NGAO on 8-10m’s & future ELTs using integral field units (single or multiple) • Dynamical state, SF - density relations, assembly histories etc z=2.38 z=2.18 Genzel et al: VLT+Sinfoni Law et al: Keck+LGSAO+OSIRIS

  17. Keck/OSIRIS IFU + LGS (Sept 2007). LGS delivers 75mas resolution BUT: x25 magnification so this is effectively ~8 mas in source plane Gravitational Lensing + AO : A Preview of the Future `Cosmic Eye’: a lensed z=3.07 Lyman break galaxy HST/ACS image Keck AO + OSIRIS

  18. Ground-based Synergy (2015-2025): TMT/JWST TMT and other ELTs will offer the combination of all NGAO gains discussed earlier plus that of increased aperture and resolution See http://www.tmt.org/foundation-docs/index.html

  19. Giant Segmented Mirror Telescope Science Working Group Report JWST: - Full sky coverage - 0.6-27 m wavelength range - Superior imaging 1-2.2 m - Stable diffraction limited > 2.2 m - High dynamic range ELT: - 25 light grasp - optical sensitivity with 15’ field - 5 better angular resolution - Superior R>3000 1-2.2 m - High spectral resolution capability - Upgradeable

  20. WFE=170 nm (on axis) and < 2 mas image motion at first-light Upgrading to WFE of 120 nm subsequently

  21. Laser Guide Star Facility • An extrapolation of existing LGSF architectures, designs, and components • CW solid-state lasers • Launch telescope behind TMT M2 • Mirror-based beam transfer optics • Safety and control systems derived from Gemini LGSF • Conceptual design review passed in March 2006 • Laser room sized for physical dimensions of 3 current-generation 50W laser systems to produce 6 25W beacons for NFIRAOS • Will monitor future development of advanced components for potential architecture upgrades • Pulsed lasers • Fiber optic beam relays

  22. Resolved Absorption Line Spectroscopy HDF-N Peak SB Central SB limit for vel. dispersions redshift Resolved z>1 stellar work is demanding in photons - only possible with TMT! 2 arcmin field ok for clusters, 5 arcmin field necessary for field galaxies

  23. Theorists’ View of Cosmic Reionization Avi Loeb, Scientific American 2006 But did it really happen like this..?

  24. Probing Early Galaxies: Effect of Source Size log F (cgs) JWST NIRSpec • How small are z~10 sources? • Strongly-lensed examples have intrinsic sizes ~30mas! • Gain of TMT+AO over JWST in detection very significant TMT redshift • Abell 2218z~5.7 Ly emitter • Magnification 30 • HST size 0.23  <0.15 arcsec • Unlensed source is 30 mas • Source is < 150pc in size!

  25. TMT/JWST Complementarity In the era of TMT+JWST we probably won’t be interested in when reionization occurred but rather the physical process as tracked by the topology and structure of ionization bubbles TMT gains in sensitivity, angular & spectral resolution but not field of view JWST finds luminous sources, TMT scans vicinity to determine topology of ionized shells via fainter emitters - in conjuction with HI surveys

  26. Removing the OH Forest: the final obstacle Courtesy: Bland-Hawthorn

  27. Fiber Bragg Grating: Created Holographically Courtesy: Bland-Hawthorn

  28. First device (Bland-Hawthorn et al 2004) FBG takes out 96% of OH background by suppressing 18 doublets over 70nm J H Courtesy: Bland-Hawthorn

  29. taper transition Leon-Saval, Birks & JBH (2005), Optics Letters JBH et al (2007), Optics Express

  30. Impact of Evolving Synergy • Current role of space observatories: - unique wavelength range - reduced background - angular resolution • Angular resolution is increasingly a driver in astronomy • ELTs + next generation AO will redefine the territory • Practicality of OH suppression less clear but given sufficient investment could offer great advantages in 0.7 - 2.2 m range • Unassailable advantages of space (in UVOIR range) - panoramic imaging (AO always ineffective) - optical and UV: very significant opportunities • JWST does not provide these capabilities

  31. Relevance to Science Themes of Workshop • Resolved Stellar Populations • Dark Sector Cosmology: • First Light and Cosmic Reionization: • AGN and Black Holes: • Extrasolar Planets • Some key questions: • Is there a case for a post-JWST large aperture space telescope? • Merits of the optical and UV • Broader role for JDEM given its unique potential

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