In the last several years, I have worked intensively on the supermassive star
Eta Carina, which in its great eruption 160 years ago, ejected an enormous mass
(10-20 times that of our sun) into space. In a short period of time,
astronomically speaking, the star itself may finally die in a supernova explosion.
The Hubble Space Telescope (HST) has designated our study of Eta Carina as one of
its Treasury Projects, devoting large amounts of time to studying its variations.
I'm enthralled by dirt -- at least the astronomical kind. The dust out of which
our planet formed, originally came from the stars. For many years, I have
been studying the conditions under which this dust condenses out of hotter gases.
Novae, for example, are stars that undergo non-fatal explosions that expel enormous
amounts of dust into space. I have played major roles in the decades-long
planning and development of the Spitzer Infrared Telescope, now bringing us
spectacular images of our dusty space environment. I am looking forward to using
the infrared-optimized LBT to study dust in interesting systems such as the RY
Scuti binary system, with two stars orbiting each other so closely that they touch.
My research spans the structure of our Milky Way to the study of the populations
of massive stars here and in nearby galaxies. I use our own in-house database
of a 100 million objects to map the structure of our galaxy and observations with
the Steward telescopes to study the "supernova imposters," which are very massive
stars expelling large amounts of matter into space.
I'm interested in the extremely high energy particles generated in shock waves,
both in giant clusters of galaxies on scales up to millions of light years, and
in the smaller explosions of dying stars, as they create supernova remnants. I
study these systems using radio, optical, X-ray and infrared images and spectra
from both ground- and space-based telescopes.
Understanding how galaxies are formed and evolve presents arguably the biggest
challenge for astrophysics in the next decade. As new observing facilities
come on-line, we can look back to the earliest ages of our universe and
learn more about galaxies in their infancy. I am currently conducting a parallel
approach by studying the nearest dwarf galaxies which are the most numerous
galaxies in the Universe and the likely building blocks of all galaxies. Like
an archaeologist, I reconstruct their lives by exploring the
fossil records by measuring the ages, metallicities, and distributions of their
oldest stars.
I am interested in the distribution of "dark matter" in the Universe, on scales
ranging from sub-galactic to those larger than clusters of galaxies. Dark matter
is the dominant matter component in the Universe, yet its nature has eluded us
so far. I study gravitational lensing of high redshift sources, and dynamics
of individual galaxies and clusters, to gain detailed knowledge of the clustering
properties of dark matter.
One focus of my current research is the study of solar system comets, which are
frozen reservoirs of primitive solar dust grains and ices. I analyze the
composition and size distribution of cometary dust grains from infrared imaging
and polarimetry techniques using the LBT and Steward Observatory telescopes which
support my Spitzer Infrared Telescope activities. In this way, I can determine the
physical characteristics of the solid materials that constituted the primitive solar
nebula, out of which planetesimals, then planets, and eventually we, ourselves,
were formed.
Deep inside a star, the churning and the transfer of massive amounts of energy
are not open to direct observation. However, through the use of sophisticated
physical models and numerical simulations on supercomputers, we can investigate
how these invisible processes work. Recently, we have been concentrating on the
convection processes in stars near the end of their red giant phases.
Our observational colleagues can search for the subtle signatures of these processes,
and improve our understanding of the hidden interiors of stars.
I am an infrared astronomer who specializes in measuring the polarization of
light. This type of observation can reveal the structure of dust in comets,
the magnetic field geometry in galaxies and pinpoint the location of hidden
stars. Specialized observing procedures are required, but a few major
facilities such as the NASA IRTF and the Hubble Space Telescope have a
polarimetric capability I am able to use. We are building a precision infrared
imaging polarimeter for use on the MMT in combination with the AO secondary.
I do research in theoretical and computational astrophysics, mainly
addressing problems associated with very energetic phenomena and their
impact on the universe. My students and I carry out large fluid dynamical
simulations including specially developed routines to follow the microphysics
responsible for the emission we observe from such astronomical objects as
supernova remnants, active galaxies and clusters of galaxies.
Our calculations can be compared directly with observational data
to test basic theories about the origins of these objects.
Profile: Dr. Sebastian Hidalgo
My research is focused on the star formation history of dwarf galaxies and their extended structures (low surface brightness regions at relative distance from the center). This give us reliable information about how stellar populations of dwarf galaxies evolve as a function of the metallicity and time. Extended structures of dwarf galaxies are fossil records of the first stages of their evolution. Studing the star formation history and the distribution of the stellar populations of this extended structures would cast light on the formation and evolution of dwarf galaxies and, if they are the building blocks of the Unvierse, for other bigger galaxies. The color-magnitud diagram is the best tool to study and derive the star formation history. I work with deep HST data, synthetic color-magnitud diagrams and powerfull algorithms to obtain this information.
Profile: Crystal Austin
I am a 5th year graduate student working with Prof. Williams. My
disertation uses semi-analytic and N-Body simulations to study dark matter
halos.
I am a graduate student working with Chick Woodward, Bob Gehrz, and Evan Skillman. I use the
Spitzer Space Telescope to study evolved stars in globular clusters and Local Group dwarf galaxies. The amount and composition of circumstellar dust around these stars reveal details about stellar mass loss, a vital component of galactic evolution. Mass loss in stars lacking heavy metals also teaches us about the mechanisms of dust production in the early universe, when the metals that dust grains condense from were scarce.
Profile: Shea Brown
It is predicted that a large fraction of the total baryons in the universe
reside outside the well studied dense clusters of galaxies. Cosmological
simulations show a universe where rich clusters and super-clusters of
galaxies are connected by a diffuse "cosmic web" of sheets and filaments,
but these regions are difficult to detect precisely because they are such
low density environments. My research, in collaboration with Prof. Larry
Rudnick, focuses on using non-thermal emission to detect and characterize
these low density regions, using powerful telescopes such as the Very
Large Array, the Greenbank Telescope, and the Westerbork Synthesis Radio
Telescope array. Our current focus is on using polarization observations
to detect very low surface brightness emission purportedly cause by shocks
related to large scale structure formation.
Profile: Jennifer Delgado
I'm a first year graduate student with an interest in planet formation. In
particular I am interested in the early solar system enviroment and
extra-solar circumstellar dust disks.
Profile: Paul Edmon
I am a graduate student working for Tom Jones. We have developed a code
that tells us the radiation from and energy losses to cosmic rays. We are
currently using this code in conjunction with simulations of actual Supernova
Remnants (such as SN 1006 and RX J1713.7-3946) to see if we can match the
observed radiation coming from these sources. This helps us to verify our
cosmic ray acceleration models and to understand how these interesting
objects work. In the future we hope to use this code to model the
radiation from other simulations that include cosmic rays, such as Jet
Models and Cosmological Simulations.
I am a second year graduate student working with Larry Rudnick on the young
supernova remnants Cassiopeia A and Kepler. I use infrared and X-ray images
and spectra of Cas A, as well as optical, X-ray, and radio observations of
Kepler's supernova remnant, to understand the structures and physical
processes occurring in the remains of these recently deceased stars. We are
currently trying to understand how supernovae contribute to the dust content
of the Universe, how elements formed in stars get incorporated into the
interstellar medium, and what causes the assymmetries of supernova remnants.
Profile: Damon Farnsworth
I am a first year graduate student. I've recently been researching cosmology and gravitational lensing under Liliya Williams. My general research interests lie in the computational and theoretical aspects of cosmology, large-scale structure formation and evolution, and gravitational astrophysics. In my limited spare time I sleep and eat.
Profile: Andrew Helton
I am a graduate student working under the direction of Chick Woodward and Bob Gehrz. My research primarily involves the evolution of classical and recurrent novae using data obtained with the
Spitzer Space Telescope and multiple ground based observatories including Gemini, IRTF and our own Mt. Lemmon Observatory. Ultimately, these observations should provide further insight into the physical processes involved in novae outbursts, the dynamics of the ejecta, the formation and evolution of dust, and how the ejected material interacts with the interstellar medium and contributes to local chemical enrichment.
I am a graduate student currently working with Prof. Larry Rudnick on the
supernova remnant Cassiopeia A. I am most interested in medium and large
scale X-Ray variability using data from the Chandra X-Ray Observatory.
One aspect of my research is to observe detailed changes in the spectrum
of Cassiopeia A. This can give us information about how Cassiopeia A's
shocks interact with the ejecta from the supernova. I also supplement the
X-Ray data with IR data from the Spitzer Space Telescope in order to
further study radiative processes in this interesting astronomical object.
Profile: Kristy McQuinn
I am a 5th year graduate student working with Dr. Evan Skillman to
determine the duration of starbursts in nearby dwarf galaxies. A starburst
is an episode of intense star formation in a galaxy that affects not only
the structure and evolution of the host galaxy but also the chemical
composition of the galaxy's external environment (the intergalacitc
medium). Understanding how long a starburst lasts requires a
reconstruction of the galaxy's recent star formation history. The duration
is an important and fundamental parameter in the study of starbursts
because it affects much of the subsequent analysis and study of a
starburst galaxy's evolution. Our work uses optical images from the Hubble
Space Telescope of more than a dozen nearby dwarf systems and stellar
evolution models to determine the rate of star formation over the past 1
billion years.
I am a graduate student working under the supervision of Tom Jones in the computational astrophysics group. My current research utilizes high resolution simulations of radio jets to investigate the observational consequences of their interactions with the ICM. By including relativistic electron transport in the simulation, we have calculated synthetic radio and x-ray observations of these jets. Knowing the details of the physics in our simulations, observed properties can be directly related with physical quantities.
I am a member of the
observational
cosmology group working for Shaul Hanany to help fly the next
generation of balloon-borne cosmic microwave background experiments. We
hope to measure the polarization of the background radiation, which will
yield better values for cosmological parameters, and should constrain
inflationary models of the big bang. My current work deals principally
with designing the optical systems to be used in these experiments,
relying heavily on physical optics modeling to analyze optical
performance.
Profile: Dan Polsgrove
I am a graduate student working in the observational cosmology
group for Terry Jones and Shaul Hanany. Our goal is to fly the next
generation balloon-borne cosmic microwave background experiment. We hope
to measure the polarization of the background radiation, which will yield
better values for cosmological parameters, and should constrain
inflationary models of the big bang. I'm currently learning as much as
possible about polarization as well as optical modeling and simulation, en
route to designing a method by which to accurately calibrate the
experiment's instrumentation prior to first flight.
Profile: Gerry Ruch
I am a sixth year graduate student working under Dr. Charles Woodward. My research involves using ideas and technologies from computer science and artificial intelligence to mine astronomical archives. My primary astronomy focus is the nature of protoplanetary disks, young stellar objects that are believed to be the birthplaces of planetary systems. I am currently developing a set of automated tools to extract the physical parameters (disk density, disk geometry, dust grain properties, etc.) of the disk sources in the Spitzer Space Telescope Cores to Disks legacy program. An extraction of these parameters from a large number of sources in a consistent way will further our understanding of the exact geometry and composition of protoplanetary disks.
Profile: Tea Temim
I am a second year graduate student working with Prof. Chick Woodward in the
infrared astronomy lab. My current research involves the study of the famous
Crab nebula and N49, a young supernova remnant in the LMC that is
interacting with a massive dense molecular cloud. I use infrared images from
the Spitzer space telescope along with images at other wavelengths to try to
understand the composition, physical conditions, and the complex morphology
of these supernova remnants.
Profile: Chelsea Tiffany
I'm a first year grad student. During undergrad I worked on velocity
relationships in binary start systems, analyzing data for a pulsar and
looking at the interaction of solar winds with the Earth's magnetic
fields. I attended Wellesley College outside of Boston.
Profile: Steve Warren
I am currently working with Dr. Andrew Cole and Dr. Evan Skillman on multi-object fiber-fed echelle spectroscopic data taken with the 4.2m Herschel Telescope. I am investigating the near-infrared calcium triplet (CaT) lines of red giant stars to extend the known CaT - Metallicity relation of Galactic globular clusters to other stellar populations with larger variations of metallicities and ages. This will have a direct effect on research into Galactic and Extra-Galactic stellar populations: most notably the globular clusters of M31 (the Andromeda Galaxy) and Milky Way satellite galaxies such as the Large and Small Magellenic Clouds.
I am in my third year of graduate school working with Evan Skillman.
I primarily study star formation and its role in the evolution of
galaxies. Specifically, I use Hubble Space Telescope images of dwarf
galaxies to reconstruct their star formation histories. Because
dwarf galaxies are the building blocks of larger structures in the
universe, the history of their star formation allows us to trace
galaxy evolution from early proto-galaxies all the way to massive
spirals. Along these lines, I am interested in both ancient star
formation (e.g. the role of cosmic reionization and star formation in
the early universe) and recent star formation (e.g. understanding how
regions of star formation propagate throughout a galaxy).