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Science With a 30-Metre Telescope
A 30-metre telescope, operating in wavelengths ranging from the ultraviolet at ~320 nm to the mid-infrared at ~30 microns, is an essential tool for addressing key questions in astronomy ranging from understanding star and planet formation to unraveling the history of galaxies and the development of large-scale structure in the Universe. The 30-metre aperture not only adds substantial light-gathering power for pushing to fainter limits and/or for higher S/N observations, but enables much higher resolution imaging -- with adaptive optics (AO) systems. In addition, TMT and the James Web Space Telescope (JWST) are comparably powerful, yet complementary observatories. Their concurrent operation will enable science discoveries far beyond what either could achieve alone.
The gain with TMT over existing 8-10 metre telescopes will be huge, ranging from ~10 times for seeing-limited observations (where the gains go as D^2) to ~100 times for AO diffraction-limited observations (where the gains go as D^4). The near-infrared wide-field AO systems on TMT will provide spatial resolutions about 10 times sharper than what can be achieved by the Hubble Space Telescope in the optical at 600-800 nm, and ~5 times that achieved by JWST.
TMT will provide new observational opportunities in essentially every field of astronomy and astrophysics, while providing uniquely powerful opportunities for new discoveries and their followup. As we have seen during the decades-long lifetime of the largest ground-based telescopes (like Lick, Mt Wilson, Palomar and Keck), TMT will inevitably be at the forefront of research as new discoveries are made. As a result the TMT science community has emphasized broad capabilities in the selection of the first and second generations of instruments. However, not all science can be done with such instruments and so TMT's powerful general purpose instruments are complemented by others whose focus is on important but extremely challenging research areas like planet detection and characterization.
TMT will be a fundamental tool for investigating a very wide range of topics, including:
Spectroscopic exploration of the "dark ages" around redshift z~10-15 (only 300-500 million years from the Big Bang). This fascinating period was when the first sources of light and the first heavy elements in the universe formed and when the universe, which had recombined at redshift z~1000, began to become re-ionized by these sources of light (reionization finished around redshift 6 or about 950 million years after the Big Bang). The nature of "first-light" objects and their effects on the young universe are two of the outstanding open questions in astrophysics. Here TMT and the James Webb Space Telescope (JWST) will work hand-in-hand, with the 6-meter diameter JWST providing the targets and measurements in regions inaccessible from the ground while TMT will carry out detailed study with its high spatial resolution AO spectrometers and imagers.
Exploration of galaxies and large-scale structure in the young universe, including the era in which most of the stars and heavy elements were formed and the galaxies in today's universe were assembled. TMT will allow detailed spectroscopic analysis of galaxies and subgalactic fragments during the epoch of galaxy assembly from redshift z~10 through the peak of the star formation at redshift z~2-3 to the present day. Observations with TMT will help answer questions about the early production and dispersal of the chemical elements, the distribution of baryons within dark matter halos and the processes of hierarchical merging of subgalactic fragments. The early epoch of the formation and development of the large-scale structures that dominate the universe today should also be observable with the TMT.
Studies of the matter power spectrum on small spatial scales, using direct observations of distant galaxies and the intergalactic medium (IGM), provide information on the physics of the early universe and the nature of dark matter that are inaccessible using any other techniques.
Investigations of massive black holes throughout cosmic time. The recently-discovered tight correlation between central black hole mass and stellar bulge velocity dispersion strongly implies that black hole formation and growth is closely tied to the processes that form galaxies.
This result also suggests that supermassive black holes are at the centers of most or all large galaxies. The TMT combination of high spatial resolution and moderate-to-high spectral resolution will extend our capability to detect and investigate central black holes to cosmological distances. In addition to investigations designed to understand the black hole-galaxy growth issue, nearby supermassive black holes can be analyzed with very high physical resolution. This will allow us to measure general relativistic effects at the center of the Galaxy and to spatially resolve the accretion disks for active black holes in the centers of galaxies to the distance of the Virgo cluster.
Exploration of planet-formation processes and the characterization of extra-solar planets remain two of the most exciting, and difficult, challenges to astrophysics in the next decades. The challenge is to characterize the properties of extra-solar planets and to understand the physical processes that lead to star and planet formation. TMT will have a very important role to play in many aspects of this fundamental endeavor.
Spectroscopic discovery observations that push into the terrestrial-planet regime, the kinematics of proto-planetary disks, spectroscopic detection and analysis of extra-solar planet atmospheres and the direct detection of extra-solar planets in reflected and emitted light are all scientific goals that are driving the TMT design requirements.
Furthermore, as has been the case for every previous increase in capability of this magnitude, it is very likely that the scientific impact of TMT will go far beyond what we envision today and TMT will enable discoveries that we cannot anticipate. TMT, like its pathfinding 5-10 m ground-based predecessors, will be at the cutting edge of astronomical research for decades to come.
For more information, see our Detailed Science Case & Science Case and Fact Sheet(pdf)
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