MIT Kavli Institute for Astrophysics and Space Research
With the receipt of a generous gift from the Kavli Foundation,
MIT's Center for Space Research has been renamed the MIT Kavli
Institute (MKI) for Astrophysics and Space Research.
The MKI is one of ten centers around the world established
by the Kavli Foundation for the study of astrophysics, nanoscience,
and neuroscience.
Income
from the Kavli gift and other gifts is being used to support technology
development and the research activities of MKI.
The inaugural Kavli research program, described
further below, seeks to improve our
understanding of the mysterious dark matter and dark energy
that are the dominant constituents of our universe.
MKI conducts research in physics, astrophysics, space science,
detector engineering and related technology, and participates in
National Aeronautics and Space Administration (NASA) flight
missions. Specific areas of research include extragalactic astronomy
and cosmology, galactic astronomy, gravitational physics,
the solar system and space
plasma physics, and the space life sciences. Research conducted in
MKI is reported by the departments of Physics, Earth Atmospheric and
Planetary Sciences, Aeronautics and Astronautics, Civil and Environmental
Engineering, and Mechanical Engineering, and by the Harvard-MIT
Division of Health Sciences and Technology. MKI is the home of
the astrophysics division of the physics department, supporting faculty,
postdocs, and students. Students actively participate in research;
in the past year 42 graduate students and 28 undergraduate students
from four departments and from Wellesley College worked on projects
at MKI.
MKI supports MIT involvement in three major observatories: the
Magellan Observatory (Prof. Schechter, MIT director), the Laser
Interferometric Gravitational-wave Observatory (LIGO; Dr. Shoemaker,
MIT director), and the Chandra X-Ray Observatory (Prof. Canizares,
associate director). The Magellan Consortium operates two
6.5-meter diameter optical telescopes in Chile. The LIGO Laboratory,
a collaboration of Caltech and MIT, is engaged in developing and
commissioning gravitational wave telescopes. Recent improvements have
made the LIGO instruments the most sensitive gravitational-wave
detectors to date. The Chandra satellite was launched as a major
NASA mission in 1999 and continues to be extremely productive.
Two of the four Chandra scientific instruments were built at MKI,
the High-Energy Transmission Grating Spectrometer and ACIS, a
Charge-Coupled Device (CCD) imaging spectrometer. MKI is also active
in the Chandra X-Ray Observatory Science Center.
In addition to the major observatories, MKI is involved in several
more focused space missions.
The Suzaku (formerly Astro-E2)
X-ray astronomy mission (Dr. Bautz, MIT PI)
was successfully launched by
the Japan Aerospace Exploration Agency in July 2005. Commissioning
of the instruments, including MIT's X-ray Imaging Spectrometer,
is under way.
The HETE-2 mission (Dr. Ricker, PI), built and operated at MIT with
US and international collaborators, was launched in 2000 and is
dedicated to the detection and prompt localization of sources of
gamma-ray bursts.
The Rossi X-ray Timing
Explorer (RXTE: Dr. Levine, MIT PI) has entered its tenth year of
successful operation. MKI operates the All-Sky Monitor instrument which
continuously surveys the sky for new sources and finds interesting
targets for other observatories.
Under development in collaboration with Boston University are
the CRaTER instrument, slated for NASA's Lunar Reconnaissance
Observatory, and PICTURE, a sounding rocket mission also to be
launched by NASA.
CRaTER is designed to characterize the lunar radiation environment
for assessing its effects on human tissue and
for testing models of acceleration processes in the solar wind.
The goal of
PICTURE is to exploit the high resolution of optical interferometry
above the earth's atmosphere to image an extrasolar planet.
Research in CSR's Space Nanotechnology Laboratory (Dr. Schattenburg,
director) seeks to apply micro and nanofabrication technology to
achieve dramatic improvements in lightweight high-resolution
optical components. Recent efforts focus on developing a new optical
system for the lab's unique Nanoruler grating patterning tool that
will enable writing variable period gratings. This work is targeted
toward future NASA X-ray missions. The SNL was recently awarded a
NSF Nanoscale Interdisciplinary Research Team grant to seek ways
of applying high-accuracy diffraction gratings to problems of nano-scale
metrology.
RESEARCH HIGHLIGHTS
EXTRAGALACTIC ASTRONOMY AND COSMOLOGY
The MKI's first Kavli research program is focused on
studies of dark matter and dark energy in the context of the evolution
of the universe and our understanding of the structure of matter and
spacetime.
The Sloan Digital Sky Survey has been used to create the largest
three-dimensional map of the Universe to date. Its use in the
measurement of cosmological parameters, including the density of dark energy,
was the most cited paper in 2004
in all areas of physics.
Other
studies of dark matter have investigated the decoupling of
the dark matter in the early universe and the substructure of
the dark matter in clusters at the present time.
A new calculation of inflationary perturbations and their quantum to
classical transition has been made that drops
the usual slow-roll approximation.
On the right is an image from the Sloan Digital Sky Survey
that shows a field of galaxies detected in the survey.
Galaxies discovered in images such as this are examined
spectroscopically to determine their redshift and hence their distance.
From this information a three-dimensional map of the galaxy
distribution can be derived. On the left is a slice of the
universe that shows the distribution of 67,000 galaxies.
Each galaxy is shown as a single point with the color representing
luminosity. Using data on 205,000 galaxies, Professor Max Tegmark
and colleagues derived the
power spectrum of matter in the universe. Different cosmological
models predict different power spectra.
Tegmark's work shows that a model that includes
dark energy and dark matter is required to produce the spectrum
observed.
(Credit: Professor Max Tegmark, MKI)
The HETE satellite localization of a short hard gamma-ray burst, combined
with optical and radio followup measurements, have resulted in
the first secure determination of the source of this type of burst.
The energy scale established by these measurements and the
identification of the galaxy host as an old elliptical galaxy support
the picture that these bursts are caused by the inspiral of a pair of
neutron stars. Information on neutron-star inspiral rates
has important implications for predictions of gravitational wave sources.
In a related area,
the study of core-collapse supernovae, both as gamma-ray bursts
and as X-ray sources, is continuing.
Left: X-ray light curve for the short-hard gamma ray burst GRB050709
discovered by the HETE satellite on 9 July 2005. Features as brief as
~3 msec are detected in the 6-400 keV X-ray emission. (Credit: Dr. George
Ricker, MKI).
Right: Optical afterglow detected from GRB050709. The bullseye in the three
panels indicate: left panel, afterglow 1.4 days after the burst;
center panel, afterglow 2.4 days after the burst; right panel, image
subtraction of left and center panels. The residual image in the
right panel indicates that the afterglow has faded, confirming the
discovery. (Credit: J. Hjorth and the Danish 1.5 m Telescope)
Chandra spectroscopy has provided the first convincing
evidence that most of the baryons in the present-day universe
are in the form of a heated gas, possibly solving the "missing
baryons" problem in cosmology.
Chandra X-ray observations of galaxy clusters have been combined
with microwave-decrement measurements to constrain the three-dimensional
shape of these objects, providing information on cosmic structure
formation. Comparison of Chandra X-ray and weak-lensing mass estimates
shows that X-ray measurements of clusters can yield accurate masses
even when the clusters are not relaxed. This result suggests that an
X-ray survey of clusters could provide useful constraints on the properties
of dark energy.
GALACTIC ASTRONOMY
Investigations into the nature of black holes, neutron stars and related
objects continue with emphasis on exploration of the detailed properties
of such objects in binary systems in the Galaxy.
The high time resolution of the RXTE satellite was used to
establish a link between the well-known quasiperiodic oscillations in
suspected
black hole binary systems and the existence of iron lines broadened
by kinematic and gravitational effects. These measurements support
the interpretation that infalling matter is forming an accretion disk
with properties that are characteristic of the environment immediately
surrounding a black hole.
Other recent experimental work
has focused on new sensitive techniques to unveil basic
properties of binary systems, such as orbital periods and pulsations.
The past year notably saw the orbital properties of one system
revealed through absorption by a stellar wind.
The hot-spot model for quasi-periodic oscillations of
accretion disks in black-hole binary systems has been extended to
provide tentative explanations for some of the timing phenomena of
these systems.
Chandra observations have revealed a remarkable overabundance of
transient X-ray binaries in the central parsec of our galaxy, providing
evidence that tens of thousands of stellar-mass black holes and neutron
stars may be swarming about our galaxy's central supermassive black hole.
Chandra spectroscopic measurements have solved the "solar model
problem" by showing that the abundance of neon in sun-like stars
is larger than previously thought, removing a troubling discrepancy
between models and inferences of the depth of the convective layer.
Searches for gravitationally redshifted lines from the
atmospheres of neutron stars are under way, a probe
of the stars' compactness.
Detailed spatially-resolved spectroscopic measurement done by
Chandra of supernova remnants is unraveling the dynamics of these
systems and testing long-standing theories
concerning the mechanisms responsible for accelerating particles
to high energies.
Studies of the interstellar medium combined with new atomic cross
section models have yielded an unprecedented understanding of the
abundance and ionization states of oxygen.
GRAVITATIONAL PHYSICS
Data from LIGO have been analyzed for gravitational waves from a variety
of astrophysical sources, including compact binary coalescences,
periodic sources, impulsive sources, and a stochastic background.
A directed search for waves from gamma ray bursts was also undertaken.
No gravitational waves have yet been detected, but the first papers
reporting upper limits have been published.
Complementing the ground-based LIGO detectors,
a space-based interferometric gravitational
wave mission (LISA) is being planned by NASA for launch early
in the next decade.
Extensive theoretical studies
predicting the properties of gravitational-wave sources detectable
by LISA are under way.
Results are promising for the mergers of black holes at the centers of
galaxies, and
for the inspiral of stars into these black holes.
Detailed study of the waveforms of these objects will test
general relativity and reveal the evolution of supermassive black holes
at the centers of galaxies.
THE SOLAR SYSTEM AND SPACE PLASMA PHYSICS
A rare alignment of Pluto's moon Charon with a background star
was captured by a number of telescopes, including one of MIT's
Magellan telescopes.
The dimming and brightening of the starlight by Charon was
recorded in high-speed photometric measurements which
will be used to determine whether Charon has an atmosphere.
In continuing studies of the giant planets,
simultaneous observations have been made of the X-ray, ultraviolet,
and radio flux from Jupiter and Saturn, constraining models
of their magnetospheres and their interaction
with the solar wind.
MKI scientists
study plasma in the solar wind using instruments on three spacecraft:
IMP 8, WIND, and Voyager II.
In December 2004, the Voyager I spacecraft entered the solar system's
final frontier, a vast turbulent expanse where the Sun's influence ends
as the solar wind crashes into the thin interstellar plasma. Future
measurements by this spacecraft and by Voyager II will, remarkably,
provide an
in situ
probe of the shocked interstellar medium.
An innovative theory of complexity in space plasmas in the Earth's
magnetosphere and ionosphere, the solar corona, and the solar wind has
been developed using the concepts of forced and self-organized
criticality, topological phase transitions, and multifractal measures.
HUMAN SPACE FLIGHT
The Man Vehicle Laboratory continues active ground-based research
programs on artificial gravity, disorientation countermeasures, and
the study of locomotion in partial gravity.
Research on concepts for advanced space suits continues with the
development of several technology prototypes for producing mechanical
counter pressure. Physiological tests are being conducted to determine
suitability for use in planetary surface exploration space suits.
Investigations of visuomotor and orientation
functions in astronauts on the Space Station are planned.
INSTRUMENTATION FOR THE FUTURE
Looking toward future missions, high performance X-ray sensors
are being investigated in collaboration with MIT's Lincoln Laboratory.
Event-driven CCD's are under development for NASA's
Constellation X mission,
and promise to reduce greatly the power requirements for
future astronomical X-ray CCD cameras.
In another development with astronomical applications,
single X-ray photon
counting by a CMOS active pixel sensor has been demonstrated at room
temperature.
A new program directed toward the use of X-ray sensors for celestial
navigation has been initiated.
Two new spectrometers and
an adaptive optics system for the Magellan telescopes are under development.
With Haystack Observatory, work continues on the development of a
large low-frequency radio array, with the design being optimized
for cosmological studies.
The design and development of the next generation
Advanced LIGO detector is continuing; it received NSB approval this
year and appears in the President's budget for 2008 funding.
The timetable calls for starting the installation of the new detectors
in 2010.
Studies for future NASA gravitational wave missions are under way,
including LISA and the Big Bang Observer.
Research continues on sub-quantum-limited interferometric
detectors that make use of squeezed states of light or vacuum.
One of three test antenna "tiles" at Mileura Station
in Western Australia. Built at Haystack Observatory,
these tiles are being tested in the field in preparation
for the construction of an array of 500 elements.
Each tile consists of sixteen crossed-dipole low frequency
antennas, connected together electronically to form a single
unit.
The operating frequency range is 80-300 megahertz.
The Mileura Widefield Array has as one of
its goals the detection of
the neutral hydrogen gas that is believed to have existed in
the universe before the formation of stars and galaxies.
Mapping this primordial
hydrogen will give us important information about
the process of structure formation and about the
initial conditions of fluctuations established during the
inflationary epoch of the early universe.
(Credit: Dr. Colin J. Lonsdale, Haystack Observatory)
EDUCATION AND PUBLIC OUTREACH
(Dr. K. Flanagan, director) The MKI Education and Public Outreach
Office has built on existing partnerships with community-based
organizations in Boston to provide new opportunities for science
learning to underserved communities. To this end a new program
was developed to train after school professionals in the use of
the "Chandra After School Astronomy Project" curriculum and make
the program available at many sites. A development based on previously
successful summer programs, the new Chandra Astrophysics Institute
makes use of the MIT TEAL (Technology Enabled Active Learning)
studio to stimulate in depth learning in astrophysics and data
analysis for students from underrepresented groups and their teachers.
As in previous years, MKI hosted high school
students participating in the Research Science
Institute program at MIT.
More information about this center can be found on the World Wide Web
at http://space.mit.edu
Jacqueline N. Hewitt