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List of
colloquium talks given during the summer of 2015
Links to:
Program of the SAO Summer Intern Symposium, August 13, 2014
2015 Summer Program Calendars for June
, July
, and August
Abstracts for posters presented at the January 2016
AAS Meeting
INTERN: Huanqing Chen (Nanjing University)
ADVISOR:Dr. Christine Jones (HEA Division CfA)
PROJECT TITLE: Identifying Sloshing Cold Fronts in the Galaxy Cluster
Abell 2204
Abstract:
INTERN: Erin Fong (Tufts University )
ADVISOR:Dr. Peter Williams (OIR Division CfA)
PROJECT TITLE: Measuring Rotation in a Million Very Cool Stars
Abstract:
The REU student and I will work together to gain insight into this
puzzle by measuring rotation periods from photometric data of a sample
of about 1,000,000 very cool stars in the Pan-STARRS1 Medium Deep
Survey (MDS) data set. I will simultaneously lead a study of flaring
in the same stars and our two projects will build on a common target
catalog and photometric database that I am constructing. The MDS data
set is a unique resource, comprising about 100 TB of data, and the
student will learn "Big Data" analysis and statistical techniques in
Python while using Harvard's Odyssey computing cluster. The student
will write a research paper presenting her or his measurements in a
subset of the survey footprint, and our goal will be submission to
the Astrophysical Journal.
ADVISOR:Dr. Cara Battersby (RG Division CfA)
PROJECT TITLE: Extreme Star Formation in the Center of Our Galaxy
Abstract:
The student will collaborate with our Legacy Survey Team working to
observe the center of our Galaxy at high resolution and long
wavelengths using the Submilimeter Array. Observations from year 1 of
the survey are complete, and the student will work with fully
calibrated and reduced data from the survey to investigate the
properties and star forming activity of clouds in our Galactic
Center. This is a relatively unexplored region of the Galaxy, with
many mysteries to solve and discoveries to uncover. Understanding how
stars form (or why they don't) in such an extreme environment is key
to building a global model for the fundamental process of turning gas
into stars.
ADVISOR: Dr. Blakesley Burkhart (TA Division CfA)
PROJECT TITLE: A Study of Lyman Alpha Cloud Properties Using the
ILLUSTRIS Cosmological Simulation
Abstract:
ADVISOR:Dr. Sarah Willis (OIR Division CfA)
PROJECT TITLE: Emission Line Imaging in Massive Star Forming Regions
Abstract:
ADVISOR: Dr. Atish Kamble (TA Division CfA)
PROJECT TITLE: Radio Spectacle from Supernovae in the Local Universe
Abstract:
Our team uses radio, optical and X-ray observations to address some
of the most fundamental questions that can be asked about supernovae:
What are the progenitors that give rise to the rich diversity among
supernovae? How do the stars shape their environment leading up to
the supernovae? Do black-holes drive energetic supernovae? In this
project, depending on the student's inclination he/she will be
involved in either observational or theoretical aspects of
investigating supernovae.
ADVISOR: Dr. Ralph Kraft (HEA Division, CfA)
PROJECT TITLE: Determining the Emission Mechanisms of the Extended
Radio and X-ray Emission in the Galaxy NGC1052
Abstract:
ADVISOR: Dr. Alicia Soderberg (TA Division CfA)
PROJECT TITLE: Supernova Forensics: A Stellar Investigation from
Cradle to Grave and Beyond
Abstract:
ADVISOR: Dr. Georgiana Ogrean (HEA Division CfA)
PROJECT TITLE: Systematic Uncertainties in Characterizing the
Outskirts of Galaxy Clusters
Abstract:
Significant systematic uncertainties often make spectral analyses of
galaxy cluster outskirts particularly controversial. While the limits
to which XMM-Newton can characterize cluster outskirts have been
investigated, a similar Chandra study has yet to be carried out.
In this project, the student will analyze archival Chandra
observations of a large sample of galaxy clusters. The student will
push Chandra's X-ray capabilities to the limit by measuring the
density, temperature, pressure, and entropy profiles of the clusters
as far out in the outskirts as possible. The student will evaluate the
statistical and systematic errors associated with the measurements,
and develop robust indicators to determine the limits at which
systematic uncertainties bias spectral measurements performed with Chandra.
ADVISOR: Dr. Jayne Birkby (SSP Division CfA)
PROJECT TITLE: Exoplanet Light Curve Studies
Abstract:
ADVISOR: Dr. Matt Ashby (OIR Division CfA)
PROJECT TITLE: Luminous Merging Galaxies
Abstract:
CO-ADVISOR/MENTOR: Dr. Felipe Andrade Santos (HEA Division CfA)
The hot gas in clusters can be perturbed by interactions between
clusters. We will investigate the sloshing of the hot gas in the
cluster Abell 2204 using deep Chandra observations. In particular, we
will determine the locations of sharp discontinuities in the X-ray
surface brightness and measure the gas temperature across these
regions to test that these are cold fronts due to sloshing and not
due to shocks. We will also examine the larger region around the
cluster to search for the perturbing system. Finally, we will
compare the X-ray morphology with that of other sloshing clusters
and with simulations.
CO-ADVISOR: Prof. Edo Berger (OIR Division CfA)
Stars are born rotating rapidly but gradually slow down over their
lifetimes. There's a great deal of interest in understanding this
process because it implies the possibility of "gyrochronology":
inferring a star's age, an important and hard to measure quantity,
from its rotation rate. Stellar spin-down varies with properties
such as mass and metallicity, though, and a key finding is that very
cool (low-mass) stars behave strangely: they seem to rotate rapidly
for a long time, then spin down suddenly.
INTERN: Elizabeth Gehret (Northern Arizona University )
CO-ADVISORS/MENTORS: Drs. Eric Keto and Qizhou Zhang (RG Division CfA)
We are searching for a summer intern to investigate extreme star
formation in the central region of our Galaxy. The center of our
Galaxy hosts a supermassive black hole and the densest reservoir of
molecular gas in the Galaxy. However, the best measurements to date
suggest that this region seems to be breaking star formation laws
and under-producing stars by about an order of magnitude. Is there a
population of newly formed stars missed by previous observations that
explains this discrepancy? Can we explain the dearth of star
formation by high turbulence or magnetic fields?
INTERN: Alex Gurvich (Carnegie Mellon University)
The student will analyse formation of low column density structures in
the ILLUSTRIS simulation. The work will involve becoming familiar
with cosmological N-body simulation techniques and how to use the
resulting data products. We hope to improve understanding of the
size distribution of Lyman alpha clouds and small galaxies and derive
predicted galaxy and cloud properties.
INTERN: Kendall Hall (California State University, Fresno )
CO-ADVISOR: Dr. Joe Hora (OIR Division CfA)
Young high mass stars pour energy into surrounding molecular clouds,
heating the dust and ionizing and eventually dispersing the gas. We
have obtained high spatial resolution maps of 6 galactic massive
star forming regions with narrow band near-infrared filters that
select for ionized BrG at 2.17 microns and molecular hydrogen, H2, at
2.12 microns. These regions have previously identified populations
of several thousand young stellar objects. The H2 line is typically
excited when high velocity outflows from young stars collide with the
surrounding interstellar medium. The student will use
continuum-subtracted H2 maps to identify candidate outflows and will
identify spatially associated young stellar objects that are
candidate driving sources. The student will measure the integrated
flux in BrG for each region and calculate a BrG-traced star
formation rate. These will be compared to previously determined star
formation rates from young star counts and mid-infrared star
formation tracers to better understand the overall activity of each region.
INTERN: Louis Johnson (University of the Pacific )
CO-ADVISOR/MENTOR: Dr. Raffaella Margutti (OIR Division CfA)
Supernovae are among the brightest astronomical sources in the
universe. These are the death throes of massive stars giving birth
to objects such as white-dwarfs, neutron stars and black-holes. Due
to the extreme conditions that occur in supernovae, they are also
the laboratories for extreme physics. The strong shock wave
unleashed in a supernova heats up the environment to high
temperatures. The resultant plasma produces emission in radio and
X-rays, providing the best evidence of prevailing conditions in the
supernova. We observe this emission using sensitive telescopes
around the world and use it to draw inferences about the fateful
star to advance our knowledg about their evolution.
INTERN:Taylor Morris (Sewanee: The University of the South )
CO-ADVISORS/MENTORS: Dr. Christine Jones (HEA Division, CfA)
The elliptical galaxy NGC1052 has a very bright X-ray nucleus as well
as extended X-ray and radio emission. Kadler et al. (2004) analyzed
a short (2 ks) Chandra observation. In this project we will analyze
a long 60 ks Chandra observation, in addition to two shorter Chandra
observations, as well as 5 XMM-Newton observations, Suzaku and ROSAT
(HRI and PSPC) observations. In the radio, there are both VLBI and
VLA observations. Finally there also are HST observations of NGC1052
(von Dokkum et al 1995). Although much of the extended X-ray
emission corresponds to radio features, the deep Chandra
observations suggest there is more extended X-ray emission on the
scale of a group of galaxies. This project will determine the X-ray
luminosities and spectra of the various small scale X-ray components
and compare these with radio emission to determine the primary
emission mechanisms. We will also determine the gas properties of
the more extended X-ray group emission, in particular if there is
sufficient cooling at the center to feed the nuclear emission as well
as the effects of the gas on the X-ray emission from the extended
radio arms.
INTERN: Sarafina Nance (University of Texas, Austin )
CO-ADVISOR/MENTOR: Dr. Jerod Parrent (TA Division CfA)
The study of supernovae explosions has long focused on the strong
radioactively-powered optical signal that dominates the bolometric
luminosity in the weeks following one of these monster
explosions. However, some of the most profound advances in our
understanding of supernovae and their progenitor systems has been
revealed through synergistic observations at other wavelengths
including X-ray, gamma-ray, and the radio/mm-bands. In parallel with
these observational efforts, theoretical modeling of the final
evolutionary stages of stars has shed light on the final decades in
a star's life. We propose a CfA REU student project designed to
tackle the outstanding questions on one recent SN explosion from
2014 by combining data (already in hand) with MESA modeling of the
putative progenitor star Through this project we aim to extract the
physics of the explosion, properties of the environment and history
of the progenitor star/system.
INTERN: Jennie Paine (Virginia Tech )
CO-ADVISOR/MENTOR: Dr. Paul Nulsen (HEA Division CfA)
Galaxy clusters are the most massive gravitationally-bound structures
in the universe. In clusters, the space between galaxies is permeated
by diffuse, hot plasma called the "intercluster medium", which
radiates via thermal bremsstrahllung at X-ray wavelengths. Clusters
grow hierarchically by mergers with other clusters and by accretion of
gas, and the footprints of this growth process are recorded in the
outskirts of galaxy clusters. However, because the surface brightness
is very low in the outskirts, X-ray studies of the outer regions of
galaxy clusters are challenging. Spectra of cluster outskirts have a
low number of source counts relative to background counts, which makes
it crucial to correctly characterize the systematic errors associated
with the spectral modeling.
INTERN: Brianna Thomas (Howard University)
Project will study the geometry of a hot Jupiter orbital system,
calculate transit probabilities and the nature of any transit light
curve. The student will test algorithms to examine the RV times series
of a known transiting planet, possibly making observations with
robotic telescopes to obtain new data and measure the planet's radius.
INTERN: Gabriel Vasquez (Florida State University )
CO-ADVISOR/MENTOR: (Dr. Howard Smith (OIR Division CfA)
Project would be to reduce and help analyze all the Herschel SPIRE (250
micron - 650 micron) Fourier Transform spectra of all (about 40) the
luminous merging galaxies in our program. We have another student
working on the Herschel PACS spectra of these objects, and between
the two of them, we'll have complete coverage. The science goal of
this study is to understand how physical conditions in the galaxies
vary as a function of the star formation rate.
INTERN: William Waalkes (University of Michigan)
CO-ADVISOR/MENTOR: Prof. Karin Oberg (SSP Division CfA)
PROJECT TITLE: Spatial Distribution of Small Organics in Prestellar and Protostellar Cores
Abstract:
Formaldehyde (H2CO) and methanol (CH3OH) are key species in the
synthesis of more complex organic molecules, like amino acids and other
prebiotic molecules. They also have great potential as molecular
probes of a range of interstellar environments. It is therefore of
great interest to understand how these molecules form. Theoretically,
H2CO can form both in the gas-phase and on the surface of dust grains,
while CH3OH is thought to form exclusively through grain surface
chemistry. These different formation pathways should manifest
themselves as different spatial distributions of H2CO and CH3OH line
emission in star forming regions. Few detailed studies exist, however,
that compare the spatial distributions of H2CO and CH3OH, and the main
formation mechanism of H2CO in different interstellar environments is debated.
The goal of this project is to characterize the emission of H2CO and CH3OH, as well as other species, in two sources ( one prestellar and one protostellar) with known physical structures (density and temperature) to answer the following questions:
What are the spatial distributions of small organics such as H2CO and CH3OH in a prestellar and protostellar core, and how do they relate to the thermal and density structure and to each other?
Which organics have principally a grain chemistry origin? If a molecule can form both in the gas and on the grains, what regulates with pathway dominates?