Science With a 30-Meter
Telescope
A 30-meter telescope, operating in wavelengths
ranging from the ultraviolet to the mid-infrared,
is an essential tool to address 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-meter
aperture permits the telescope to focus more sharply
than smaller telescopes by using the power of diffraction
of light. The large aperture also collects more light
than smaller scopes, allowing images of fainter objects.
TMT will therefore reach further and see more clearly
than previous telescopes by a factor of 10 to 100
depending on the observation.
In
addition to providing nine times the collecting area of the
current largest optical/infrared telescopes (the 10-meter Keck
Telescopes), TMT will be used with adaptive optics systems to
allow diffraction-limited performance, i.e., the best that the
optics of the system can theoretically provide. This will provide
unparalleled high-sensitivity spatial resolution more than 12
times sharper than what is achieved by the Hubble Space Telescope.
For many applications, diffraction-limited observations give
gains in sensitivity that scale like the diameter of the mirror
to the fourth power, so this increase in size has major implications.
TMT will provide new observational opportunities in essentially
every field of astronomy and astrophysics. Because of the decades-long
lifetime of TMT and the often-rapid advancement of astronomy into
new areas, broadly useful capabilities have been emphasized, while
maintaining specific capabilities needed to address key programs
that are known now.
TMT will be a fundamental tool for investigating a very wide
range of topics, including
- Spectroscopic exploration of the "dark ages" 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, became re-ionized by these sources of light. The
nature of "first-light" objects and their effects on the young
universe are among the outstanding open questions in astrophysics.
Here TMT and the James Webb Space Telescope (JWST) will work
hand-in-hand, with JWST providing the targets for detailed
study with TMT’s spectrometers.
- 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. 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
super massive 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. Two of the most exciting challenges
to astrophysics in the next decades are to understand the physical
processes that lead to star and planet formation and to characterize
the properties of extra-solar planets. TMT will have a very
important role to play in many aspects of this 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 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.
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A
numerical simulation of a planet-forming disk. The “gaps” produced
by the gravitational effects of forming planets can be inferred
by exploiting the light gathering power of TMT to feed a sensitive
infrared spectrograph capable of “deconstructing” the structure
of the disk.