Instruments and Science with TMT

Shude Mao

Outline

• International context• Telescope overview

and science instruments

• Some key science areas

• Summary

Golden era for astronomy

– All ~billion, international collaborations– Synergies between different telescopes in multi-wavelength

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LOFAR, LSST, IXO, …

LAMOST,FAST, Dome-A, TMT, …

JWST TMT

ALMASKA

Big questions for astronomy (US decadal report)• How did the universe begin?

• What were the first objects to light up the universe and when did they do it?• How do cosmic structures form and evolve?• What are the connections between dark and luminous matter?• What is the fossil record of galaxy assembly and evolution from the first stars to

the present?• How do stars and black holes form?• How do circumstellar disks evolve and form planetary systems?• How do baryons cycle in and out of galaxies and what do they do while they are

there?• What are the flows of matter and energy in the circumgalactic medium?• What controls the mass-energy-chemical cycles within galaxies?• How do black holes work and influence their surroundings?• How do rotation and magnetic fields affect stars?• How do massive stars end their lives?• What are the progenitors of Type Ia supernovae and how do they explode?• How diverse are planetary systems and can we identify the telltale signs of life

on an exoplanet?• Why is the universe accelerating?• What is dark matter?• What are the properties of the neutrinos?• What controls the masses, spins and radii of compact stellar remnants?

• Many of these questions require new surveys, telescopes, instrumentations ……

• GSMT (TMT/GMT) was ranked as the highest priority in ground-based experiments in the 2000 decadal report

• Number three in the 2010 report•Number one by the optical/IR panel.

TMT partnership• Timeline

– 2004project start, design development– 2009preconstruction phase– 2012start construction– 2018complete, first light, start AO science

• Partnership– UC/Caltech/Canada– Japan, China, India– NSF?

• Likely the first 30m telescope in the world!!

Telescope Overview

Tensional members

M2 hexagonal ring

M2 support tripod

M2 support columns

Elevation journal

M1 cell Azimuth truss

Azimuth cradle

M2 structural hexapod

LGSF beam transfer

LGSF launch telescope

Nasmyth platform

Laser room

TMT Optical Design: Ritchey Chrétien

• M1 Parameters – ø30m, f/1,

Hyperboloid• M2 Parameters

– ø3.1m, ~f/1, Convex hyperboloid,

• M3 Parameters– Flat – Elliptical, 2.5 X 3.5m

Nasmyth Configuration: First Decade Instrument

Suite/IRMS

Key elements of TMT• Large aperture (30m vs. current 8-10m vs. 2m in

China)– Integration time t ~ 1/D2 for seeing limited

observations• Adaptive optics in near-IR

– Five times better resolution than HST at 1 micron– t ~ 1/D4 dependence for the same S/N ratio for point

sources• Due to larger aperture (D2), and small footprint in

the PSF (1/D2)• Optimised for near-IR

– Important for studying high-redshift universe and many astrophysical applications.

Power of diffraction limited observations

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3.3’x3.3’

Instruments and Science capabilities

Instrument Spectral Resolution Science Case

Near-IR DL

Spectrometer & Imager

(IRIS)

~4000

Assembly of galaxies at large redshift

Black holes/AGN/Galactic Center

Resolved stellar populations in crowded fields

Astrometry

Wide-field Optical Spectrometer

(WFOS)1000-5000

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

Multi-slit near-DL near-IR Spectrometer

(IRMS)2000 - 5000

Near-IR spectroscopic diagnostics of the faintest objects

JWST follow-up

Mid-IR Echelle Spectrometer & Imager (MIRES)

5000 - 100000 Physical structure and kinematics of protostellar envelopes

Physical diagnostics of circumstellar/protoplanetary disks: where and when planets form during the accretion phase

ExAO I

(PFI)50 - 300

Direct detection and spectroscopic characterization of extra-solar planets

High Resolution Optical Spectrograph

(HROS)30000 - 50000

Stellar abundance studies throughout the Local Group

ISM abundances/kinematics, IGM characterization to z~6

Extra-solar planets!

MCAO imager

(WIRC)5 - 100

Precision astrometry

Stellar populations to 10Mpc

Near-IR, DL Echelle

(NIRES)5000 - 30000

Precision radial velocities of M-stars and detection of low-mass planets

IGM characterizations for z>5.5

Cosmology and Fundamental constants of nature

• What is dark Matter and dark energy?• There are many theories

– some predict variation of fundamental parameters.– Wavelengths in multiplets of redshifted UV lines in quasar spectra

are sensitive to change in alpha and mp/me

• A decade of study with 10m-class telescopes has hinted at variations at the 10-5 level.

• TMT will provide a definitive resolution with much higher S/N data.

(Srianand et al. 2004)

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High-redshift universe and IGM

• TMT can study many high-redshift objects spectroscopically– Study the physical properties of first light sources in the

universe, in synergy with JWST.• Higher source density will provide multiple lines of sight to do

3D tomography.

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Black hole astrophysics• Most galaxies (including the MW) host

massive black holes at their centres• Black hole influence radius is GM/r ~ 2

– r ~ GM/ 2

– Higher resolution implies black holes at larger distances can be resolved, resolution ~ 1.22 /D

– detectable volume increases with D3.• TMT will determine black hole masses

over a wide range of galaxy types, masses and redshifts:– It can resolve the region of influence of a

109 solar mass BH to z ~ 0.4 using adaptive optics.

• Key questions:– When did the first supermassive BHs form?– How do BH properties and growth rate

depend on the environment?– How do BHs evolve dynamically?– How do BHs feed?

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Extrasolar planet detection

• Extreme adaptive optics allow us to directly image extrasolar planets.

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Searching for origins of life

• TMT will detect the absorption signatures of gases in the atmosphere in transiting planets.

• TMT should be able to detect O2 in the atmosphere of an Earth-like planet orbiting in the habitable zone of an M star.

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Challenges for China• Several centres of excellence in

theoretical astrophysics are emerging• Observational astronomy is lagging

behind– 2m vs.10m currently– No good seeing and weather sites (Dome-

A, TMT)– We need to build up the user base

• Plan to purchase international telescopes

• Much to do in the next decade to obtain the maximum scientific yield of TMT.

Summary• TMT offers a unique opportunity for China

to leapfrog in observational astronomy– Efforts from you will determine whether the

next generation (observational) astronomers can compete globally.

• TMT will produce many exciting results in – in cosmology, extrasolar planets, black holes,

….– unknown unknown areas

• Second-generation instruments still to be finalised– China can potentially contribute in this area.