TMT the next generation of segmented mirror telescopes

TMT: the next generation of segmented mirror telescopes Jerry Nelson, UCSC GTC Inauguration Seminar GTC 2009 Jul 25 2009 July 25 1

Outline Project Introduction Telescope overview TMT key features Major science goals Science Instruments GTC 2009 Jul 25 2

TMT Mauna Kea Best highaltitude seeing 4200 m GTC 2009 Jul 25 ALMA and ELTs 2009 3

Mauna Kea 13 N site Proposed Site Area Prevailing wind A NORTH Mauna Kea Science Preserve Master Plan: Astronomy Precinct GTC 2009 Jul 25 ALMA and ELTs 2009 4

Project Introduction Time line – – 2004 2009 2011 2018 project start, design development preconstruction phase start construction complete, first light, start AO science Partnership – – – UC Caltech Canada Japan NSF? Other nations? Cost – 970 M$ (2009$) GTC 2009 Jul 25 5

GTC 2009 Jul 25 6

What is TMT? Thirty-meter aperture Filled, segmented primary Elevation axis in front of primary Active and adaptive optics UV to thermal IR Broad range of instruments GTC 2009 Jul 25 ALMA and ELTs 2009 7

TMT features 14 - 200 times the sensitivity of 8 m telescopes (D 2 - D 4 gain) 3 - 5 times the resolution of 8 m telescopes and JWST 20 arcmin field of view 5 AO modes Pointing in < 3 min Instrument change in < 10 min Calotte enclosure GTC 2009 Jul 25 8

Observatory Layout: Telescope LGSF launch telescope M 2 support tripod M 2 structural hexapod Tensional members LGSF beam transfer M 2 hexagonal ring M 2 support columns Elevation journal Nasmyth platform Laser room Azimuth cradle GTC 2009 Jul 25 M 1 cell 9 Azimuth truss

TMT Optical Design: Ritchey Chrétien M 1 Parameters – ø 30 m, f/1, Hyperboloid k = -1. 000953 – Paraxial Ro. C = 60. 0 m – Sag = 1. 8 m – Asphericity = 29. 3 mm (entire M 1) M 2 Parameters – ø 3. 1 m, ~f/1, Convex hyperboloid, k = -1. 31823 – Paraxial Ro. C = -6. 228 m – Sag = ~650 mm – Aspheric departure: 850 mm M 3 Parameters – Flat – Elliptical, 2. 5 X 3. 5 m GTC 2009 Jul 25 10

Segment Size GTC 2009 Jul 25 11

Nasmyth Configuration: First Decade Instrument Suite GTC 2009 Jul 25 12

Why build a 30 -m telescope: huge aperture advantage Seeing-limited observations and observations of resolved sources Background-limited AO observations of unresolved sources High-contrast Ex. AO observations of unresolved sources GTC 2009 Jul 25 13

Science Potential Solar system detailed studies Direct imaging planets around nearby stars Stars and stellar evolution Black holes and galaxies Nearby galaxies Distant galaxies and first light GTC 2009 Jul 25 14

GTC 2009 Jul 25 15

Distant Galaxies – TMT+AO Credit: M. Bolte • TMT with AO angular resolution 100 x better than seeing limited GTC 2009 Jul 25 16

Primary Mirror Segments TMT segmented mirror is an evolution of the Keck mirror 36 segments, 1. 8 m, in each Keck telescope 492 segments, 1. 45 m, in TMT Polishing and segment module fabrication must be “mass produced” to cost and quality TMT is working with industrial partners to compete production design, testing and cost GTC 2009 Jul 25 17

Segment Support Assembly (SSA) Design Seven Segment Assembly – Top View GTC 2009 Jul 25 18

Segment Support Assembly (SSA) Design Seven Segment Assembly – Bottom View GTC 2009 Jul 25 19

Active Control Summary Selected a = 0. 72 m for segment size Item segment size # segments # edge sensors # actuators Keck 0. 9 m 36 168 108 TMT 0. 72 m 492 2772 1476 GTC 2009 Jul 25 20

Adaptive Optics GTC 2009 Jul 25 21

Adaptive Optics Adaptive optics seriously introduces the concept of high speed, high bandwidth control – Primary aim is to remove rapidly varying atmospheric turbulence that causes image blur – Secondary bi-product is ability to remove both slowly varying and rapidly varying wavefront errors that are in the telescope As currently envisioned and used, adaptive optics is only practical in the near infrared, not the visible. Adaptive optics is technologically challenging! Result is diffraction-limited performance – AO is revolutionary – For TMT resolution of 0. 005 arcsec 100 x better than atmosphere GTC 2009 Jul 25 22

Basic Elements of Adaptive Optics Atmospheric turbulence… introduces wavefront and image quality degradations… which can in principal be compensated by a wavefront corrector… provided that they can be measured with a wavefront sensor… observing a suitable reference star GTC 2009 Jul 25 23

starlight Na laser beams (6 total) Na Laser Tomography and MCAO 35 arcsec Na layer (~10 km) “Meta-pupil” for a +/-1 arc min Fo. V 90 km Light from 1 arcmin off axis Turbulent atmosphere (~15 km) 30 m DM conjugate to h ~ 10 -12 km DM conjugate to h= 0 km GTC 2009 Jul 25 24

TMT AO NFIRAOS has two deformable mirrors- MCAO – 64 x 64 – 73 x 73 NFIRAOS laser will produce 6 laser spots – Illuminates Na layer, 90 km up in the atmosphere – 150 Watts Na power – One central spot, 5 perimeter spots Two arc minute field of view Atmosphere is tomographically reconstructed, then projected out in the direction of interest Computationally intensive – Solve 38000 x 7000 control problem at 800 Hz GTC 2009 Jul 25 25

TMT AO Early Light Architecture Narrow Field IR AO System (NFIRAOS) – MCAO LGS AO System – Mounted on Nasmyth Platform – Feeds 3 science instruments NFIRAOS: - 190 nm RMS WFS - 60 x 60 order system - 2 DMs, 6 LGS, 3 TTF WFS - 800 Hz Laser Guide Star Facility (LGSF) – Laser enclosure located within telescope azimuth structure – Conventional optics for beam transport – Laser launch telescope behind M 2 LSE AO Executive Software (AOESW) GTC 2009 Jul 25 26

NFIRAOS Interfaces with Nasmyth Platform and Client Instruments Future (third) Instrument NFIRAOS Enclosure Service Platform Optics Bench and Instrument Support Structure BTO Path LGS WFS Optics Nasmyth Platform Interface IRIS Electronics Enclosure Nasmyth Platform GTC 2009 Jul 25 27

NFIRAOS Optics Benches GTC 2009 Jul 25 28

Science instruments GTC 2009 Jul 25 29

TMT First Decade Instrument/Capability Suite Instrument Near-IR DL Spectrometer & Imager (IRIS) Spectral Resolution ~4000 Wide-field Optical Spectrometer (WFOS) 1000 -5000 Multi-slit near-DL near-IR Spectrometer (IRMS) 2000 - 5000 Mid-IR Echelle Spectrometer & Imager (MIRES) 5000 - 100000 Ex. AO I (PFI) 50 - 300 High Resolution Optical Spectrograph (HROS) 30000 - 50000 MCAO imager (WIRC) 5 - 100 Near-IR, DL Echelle (NIRES) 5000 - 30000 Science Case Assembly of galaxies at large redshift Black holes/AGN/Galactic Center Resolved stellar populations in crowded fields Astrometry IGM structure and composition 2<z<6 High-quality spectra of z>1. 5 galaxies suitable for measuring stellar pops, chemistry, energetics Near-field cosmology Near-IR spectroscopic diagnostics of the faintest objects JWST follow-up Physical structure and kinematics of protostellar envelopes Physical diagnostics of circumstellar/protoplanetary disks: where and when planets form during the accretion phase Direct detection and spectroscopic characterization of extra-solar planets Stellar abundance studies throughout the Local Group ISM abundances/kinematics, IGM characterization to z~6 Extra-solar planets! Precision astrometry Stellar populations to 10 Mpc Precision radial velocities of M-stars and detection of low-mass planets GTC 2009 Jul 25 30 IGM characterizations for z>5. 5

TMT Early Light Instrument Suite Instrument Near-IR DL Spectrometer & Imager (IRIS) Spectral Resolution Assembly of galaxies at large redshift • Black holes/AGN/Galactic Center • Resolved stellar populations in crowded fields • Astrometry • ≤ 4000 Wide-field Optical Spectrometer (WFOS) 300 - 5000 Multi-slit near-DL near-IR Spectrometer (IRMS) 2000 - 5000 Mid-IR Echelle Spectrometer & Imager (MIRES) 5000 100000 Ex. AO I (PFI) 50 - 300 High Resolution Optical Spectrograph (HROS) 30000 50000 MCAO imager (WIRC) 5 - 100 Near-IR, DL Echelle Science Case IGM structure and composition 2<z<6 • High-quality spectra of z>1. 5 galaxies suitable for measuring stellar pops, chemistry, energetics through peak epoch of gal form. • 5000 - 30000 • Near-IR spectroscopic diagnostics of the faintest objects • JWST followup Physical structure and kinematics of protostellar envelopes • Physical diagnostics of circumstellar/protoplanetary disks: where and when planets form during the accretion phase • Direct detection and spectroscopic characterization of extra-solar planets • Stellar abundance studies throughout the Local Group • ISM abundances/kinematics, IGM characterization to z~6 • Extra-solar planets! • Galactic center astrometry • Stellar populations to 10 Mpc GTC 2009 Jul 25 31 • Precision radial velocities of M-stars and detection of low-mass planets •

IRIS - Infrared imaging spectrometer imager filter wheels WFS IFUs IRIS dewar (at 77 k) 2’ Grating imager Common spectrograph and camera for both IFUs F/15 AO Focus GTC 2009 Jul 25 32

IRMS - Infrared multislit spectrometer 0. 8 - 2. 5 um cryogenic multi-slit spectrometer 2. 3 arcmin field of view 0. 06 arcsec sampling 46 moveable slits 2. 4” long Covers entire Y, J, H or K band at R = 4660 GTC 2009 Jul 25 33

WFOS - Wide-field optical spectrograph 0. 31 - 1. 1 um wavelength range Observe up to 1500 objects over a 40. 5 sq. arcmin FOV Spectral resolution 300 - 7500 Reflecting gratings / prism cross-dispersion, and fixed dichroic beamsplitter at 550 nm “Echellette” design provides up to 5 orders Full wavelength coverage, even at highest resolution, for “discovery science” Low resolution mode (single order) for maximum multiplex advantage GTC 2009 Jul 25 34

Summary TMT will be a 30 -m telescope with AO capabilities from the start – ~ 190 nm rms wavefront error over 10 arcsec – First light 2018 Very large and exciting science case 8 instruments planned for the first decade 3 instruments planned for first light – IRIS (an AO NIR integral field spectrograph and imager) – IRMS (an AO NIR multi object spectrometer (46 slits) – WFOS (a seeing-limited multiobject spectrometer with R<8000, and ~ 50 arcmin 2 coverage) GTC 2009 Jul 25 35

TMT Foundation Documents www. tmt. org/foundation-docs/index. html Detailed Science Case 2007 Observatory Requirements Document Observatory Architecture Document Operations Concept Document TMT Construction Proposal – Currently in use for funding proposals GTC 2009 Jul 25 36