Write your abstract here. PART II - Giant Magallan
Telescope to Open a New Window on the Universe.
These questions are best addressed by a telescope with the power to
detect light from very faint objects, the ability to distinguish fine
detail despite the blurring effect of the Earth's atmosphere and
sensitivity to infrared heat radiation from forming stars and planets.
The GMT, with its large collecting area and exquisite image quality,
meets the demanding requirements of extrasolar planetary studies.
Presently we are able to detect planets only by indirect means. The
GMT will allow us to make images of planets around nearby stars and,
possibly, discern their chemical compositions. Designed with high
contrast imaging in mind, the GMT will have the ability to detect faint
terrestrial-like planets in the presence of enormous glares from their
parent stars. Despite the fact that stars are fundamental galactic building
blocks, we do not yet have a deep understanding of how they form. Key
issues include understanding the distribution of stellar masses, the
number of failed “brown dwarf” stars, and the role of magnetized
outflows in the
formation of stars and planetary disks. The southern hemisphere location of the GMT provides access to the
nearest and richest regions of star formation in the Milky Way. Joint
investigations with the international Atacama Large Millimeter Array -
the next generation probe of cosmochemistry – will allow powerful
studies of the dense clouds of molecular gas and dust that harbor
forming stars and their planetary systems. Recent evidence has
shown that massive black holes are commonplace in the Universe and that
intermediate-mass Black-Holes may be wandering throughout much of
intergalactic space. Our own Milky Way contains a central Black Hole with a mass one
million times that of the Sun. There appears to be a close connection
between galaxy formation and Black Hole formation, but the mechanisms
that link the two are not understood. The typical galaxy harbors a
Black Hole containing 0.5% of the galaxy’s central stellar mass. Why
the mass of stars and that of the central singularity should be in a
constant ratio is a great mystery. Did the earliest stars and Black
Holes form at the same time, or did the Black Hole dictate the
efficiency of star formation in young
galaxies? Why are some Black
Holes (like the one in the Milky Way) dark, while others host Quasars,
the most luminous objects in the Universe? The GMT, operating with
adaptive optics to achieve its maximum resolving power, can probe the
centers of distant galaxies in unprecedented detail. Galaxies like our own Milky Way began as tiny seeds in the early
Universe. How they attained their present masses and varied shapes is
one of the forefront challenges in Astrophysics today. The physical processes, and even the time-line, of the birth of
galaxies and structure from the smooth primordial gas remains largely
the domain of theory, rather than observation. Recent gains in
observations of distant galaxies and the Cosmic Background Radiation
suggest that detection of the “first light” may not be far away. Many
critical unknowns remain: were the first objects to form stars or black
holes? Did galaxies form from the gradual agglomeration of many smaller
units, or did some of them form in spectacular bursts of star
formation? Were the first galaxies swathed in dust and thus hidden from
direct observation except at long wavelengths? We now believe that the
first luminous objects formed less than 1 billion years after the Big
Bang. The light from these first stars will be redshifted into the
near-IR region of the spectrum, between 1 and 2.5 microns - where the
GMT will have its best performance. The GMT will also have the ability to probe the signatures of Dark
Mter (80% of the mass of the Universe is in this invisible form),
primarily through its gravitational bending of light, on finer scales
than possible before. The remarkable discovery in recent years that the cosmic expansion
is accelerating rather than slowing has revolutionized our
understanding of the Universe. The Dark Energy that drives this
acceleration may be related to Einstein’s Cosmological Constant, or it
may be the manifestation of a form of exotic energy not predicted by
current theories. At present our only direct measurements of the
expansion history of the Universe come from observations of distant
Supernovae – exploding stars, some of which leave behind Black Holes. The GMT is composed of 7 mirror segments, each of which has twice
the collecting area of the current Magellan telescopes. The resolving
power of the telescope is equivalent to that of a single mirror 24.5
meters in diameter. Current ground-based telescopes cannot
probe supernovae to sufficient distances to provide a definitive test
of competing models of the Dark Energy. The GMT will allow us to
observe Supernovae to the highest redshifts and will aid in the full
characterization of the expansion history of the Universe. The GMT is an innovative approach to moving past the size limit for
casting and polishing individual glass elements. While the Magellan
telescopes each have a single mirror that is 6.5 meters in diameter,
the GMT will be built from 7 mirrors, each 8.4 meters in diameter. The
collecting area of the GMT will be 12 times that of a Magellan
telescope and its spatial resolving power will be 10 times that of the
Hubble Space Telescope. The total gain in sensitivity compared to the
6.5m Magellan telescopes is more than a factor of 100 in the
diffraction limited regime. Galaxy News Reported September 4th, 2007.