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

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

Synergistic Successes HDF: HST GRBs: Chandra/Swift 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 Transiting exoplanets: Spitzer

"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.” A Vision for Ground-Based Astronomy (1908) George Ellery Hale, Study of Stellar Evolution, 1908 (p. 242) writing about the future of the 100 inch.

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

JWST vs 8m ground-based telescope 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> < < 2.2  m (1998)

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

Performance of Keck NGS AO System 50% Strehl Miranda+UranusNeptune Titan R magnitude r 0 (cm) Courtesy: Wizinowich & Keck AO team

Performance of Keck LGS AO System 50% Strehl r 0 (cm) R magnitude NGS LGS Keck is achieving ACS resolution in K band Courtesy: Wizinowich & Keck AO team

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)

Substellar binaries 126 NGS & 30 LGS Recent Keck AO Highlights

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

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

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

< 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 –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 (~ mas) –Complementary data on dust & cold gas Ground-Space Synergy ~ 2015

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 Genzel et al: VLT+SinfoniLaw et al: Keck+LGSAO+OSIRIS z=2.38 z=2.18

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

See Ground-based Synergy ( ): TMT/JWST TMT and other ELTs will offer the combination of all NGAO gains discussed earlier plus that of increased aperture and resolution

JWST: - Full sky coverage  m wavelength range - Superior imaging  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>  m - High spectral resolution capability - Upgradeable Giant Segmented Mirror Telescope Science Working Group Report

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

23 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

Resolved Absorption Line Spectroscopy Peak SB redshift HDF-N Central SB limit for vel. dispersions 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

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

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

TMT/JWST Complementarity 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 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

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

Fiber Bragg Grating: Created Holographically Courtesy: Bland-Hawthorn

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

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

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  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

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