Schedule
![[Picture of Century Tower. Credit svazquezl
http://flickr.com/photos/svazquez/2220823285/]](graphics/century_tower.jpg)
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August 26, 2009:
Dan Fabrycky (CfA ITC)The Dynamics of Hot Jupiters: Tales Told by Transits
Abstract:
The discovery of Jupiter-mass companions to normal stars came with two surprises: planets can have few-day orbits (so-called hot Jupiters) and large eccentricities. To explain those discoveries, dynamical theories have been developed which are now be tested using the burgeoning population of transiting planets. Measurements of the inclination between a planet's orbit and its host star's equator plane reveal that several migration mechanisms may be in play. Transit timing measurements are ruling out resonant companions to close-in planets down to absurdly low masses. But if disk migration is common, this technique will likely discover numerous resonant planetary systems via the Kepler mission. Transiting planets with planetary companions will fuel detailed dynamical modeling of eccentricity driving, including inferences of tidal distortion for a hot Jupiter.
(Host: Ford)
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September 2, 2009:
Karl Gebhardt (U Texas)Black Holes and Dark Matter: New Results and Fundamental Correlations
Abstract:
Recent observational and theoretical work suggest that black holes are
essential components of galaxies. In fact, they may be one of the keys
to understanding how galaxies form and evolve. I will give a general
overview of the observational results for black holes in galaxies,
including discussion of their effects on the stellar orbital
distribution. I will focus the talk on the two extreme mass ranges,
from whether globular clusters contain black holes up to black holes
in brightest cluster galaxies. The present results suggests that the
black hole correlations span over seven orders of mass. This
concordance suggests a more intimate connection between these
different types of systems than what has previously been thought.
I will also focus on measures of the dark matter profile, which is
a main systematic uncertainty for black hole mass estimates.
(Host: V. Sarajedini)
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September 9, 2009:
Ned Wright (UCLA)The Widefield Infrared Survey Explorer - WISE
Abstract:
The Widefield Infrared Survey Explorer (WISE) is a NASA Medium Explorer (MIDEX) currently under construction which will survey the entire sky in 4 mid-infrared bands at 3.4, 4.6, 12 and 22 microns with vastly greater sensitivity than previous all-sky surveys at these wavelengths.
The WISE long wavelength channels will be very powerful for detecting Ultra-Luminous Infrared Galaxies, and WISE should detect the most luminous galaxies in the Universe. The WISE short wavelength channels will be very powerful for detecting old cold brown dwarfs, and WISE should detect the nearest brown dwarfs to the Sun. WISE will also measure the radiometric diameters of about 250,000 asteroids.
WISE will have a 40 cm cryogenic telescope, 1024x1024 arrays, a scan mirror to freeze images on the arrays while the spacecraft scans continuously, and will take 47'x47' images every 11 seconds in all four bands from an IRAS/COBE style Sun-synchronous nearly polar low Earth orbit. WISE is expected to launch in late 2009.
(Host: Kehoe)
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September 16, 2009:
Phil Armitage (U. Colorado at Boulder)Supermassive Black Hole Binary Mergers
Abstract: The final coalescence of supermassive black hole binaries
is likely the inevitable consequence of mergers of galaxies
containing nuclear black holes. Despite the fact that such
coalescences are the most energetic astrophysical events in
the Universe, they have never been observed. I will discuss
the astrophysical processes that influence the evolution
of black hole binaries prior to the onset of strong
gravitational wave emission, and present new results on the
possibility of novel electromagnetic phenomena associated
with the final merger.
(Host: Veras)
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September 23, 2009:
Norman Fitz-Coy (UF)Small Satellite Systems: Challenges and Opportunities
Abstract:
Small satellites, or smallsats, are an enabling technology for addressing the U.S. National Space Policy needs of lower-cost, more-responsive space systems. The notion of fractionating large monolithic space assets into smaller assets (smallsats) is gaining acceptance within the space community. However, transitioning to these small satellite systems introduces technical challenges to the fundamental spacecraft subsystems and the supporting infrastructure of space operation.
This talk provides an introduction to small satellite systems, identifies and discusses their technical challenges, and highlights emerging opportunities. The talk also discusses ongoing small satellite activities at UFSmall satellites, or smallsats, are an enabling technology for addressing the U.S. National Space Policy needs of lower-cost, more-responsive space systems. The notion of fractionating large monolithic space assets into smaller assets (smallsats) is gaining acceptance within the space community. However, transitioning to these small satellite systems introduces technical challenges to the fundamental spacecraft subsystems and the supporting infrastructure of space operation.
This talk provides an introduction to small satellite systems, identifies and discusses their technical challenges, and highlights emerging opportunities. The talk also discusses ongoing small satellite activities at UF..
(Host: Reba)
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September 30, 2009:
Betsy Barton (UC Irvine) Star Formation and Gas in the Lowest-Density Environments
Abstract:
The morphology-density relation, or the tendency for dense environments to host early type galaxies with little star formation, extends not only to cluster galaxies, but to all environments including the "field." Thus, many clues about the evolution of galaxies can be found in the simplest environments, small groups. Unfortunately, groups with just 2-3 members are the hardest to study because of contamination by isolated galaxies seen in projection. Using cosmological simulations as a guide, my collaborators and I have developed techniques to measure the properties of satellite galaxies in otherwise isolated systems. For the Sloan Digital Sky Survey and the 2dF Galaxy Redshift Survey, we develop an understanding of processes that remove fuel and suppress star formation in satellite galaxies, like quenching and "strangulation." I will discuss how we make the first clean measurement of the frequency and strength of triggered star formation in isolated galaxy interactions and how we use background quasars and MgII absorption to study gas abundances in the halos of a subset of the z~0.1 galaxies. I will end with a description of the status of the Thirty Meter Telescope project and its instrumentation.
(Host: Jonathan Tan)
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October 7, 2009:
Karen Kinemuchi (UF) Probing the Outer Halo Galactic Formation: The new SDSS dSph galaxies and their variable stars
Abstract:
With the discovery of new dwarf spheroidal galaxies from the Sloan Digital Sky Survey, we have a larger pool of possible candidate objects that may have influenced the formation of our Galaxy. We studied five of these new galaxies for their variable star content, specifically for the RR Lyrae variables. RR Lyrae variable stars, which belong to an old stellar population, are effectively eyewitnesses to the formation of the Galaxy, as well as useful distance indicators. I will discuss our results from our studies for five of these dwarf galaxies.
(Host: Ata)
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October 14, 2009:
Duy Cuong Nguyen (UF)Probing T Tauri stars with High-Resolution Spectroscopy
Abstract:
Surveys of young stars to date have been primarily done through high-resolution imaging, and are sensitive to wide companions, but not to those in close orbits. To remedy this deficiency, we conducted an extensive multi-epoch high-resolution spectroscopic survey of several hundred T Tauri stars in nearby star forming regions with the MIKE echelle spectrograph on the Magellan Clay 6.5-m telescope. In addition, we used data from this survey to test for evidence of disk braking, as well as, analyze accretion variability in our sample.
(Host: Jian)
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October 21, 2009:
Celine Boehm (CERN/U. Annecy, France)Why should astrophysicists care about the progress or the lack of progress done in the field of dark matter?
Abstract:
(Host: Reba)
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October 28, 2009:
Frederic Rasio (Northwestern)The Million-Body Problem: Particle Simulations in Astrophysics
Abstract:
Computer simulations using particles play a key role in astrophysics. They are widely used to study problems across the entire range of astrophysical scales, from the formation of stars and planets to the dynamics of star clusters and galaxies, and large-scale structure formation in cosmology. The "particles" can represent anything from truly microscopic particles (e.g., dark matter) to macroscopic fluid elements, entire stars, or even entire galaxies. Using particle simulations as a common thread, this talk will present an overview of computational astrophysics research currently done in the theoretical astrophysics group at Northwestern. Topics will include "core collapse" in globular clusters, hydrodynamic stellar interactions, and intermediate-mass black holes.
(Host: Ford)
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November 4, 2009:
David Schlegel (LBL)
Baryon Oscillation Spectroscopic Surveys (BOSS and BigBOSS)
Abstract:
The Baryon Oscillation Spectroscopic Survey (BOSS) is a Stage III dark energy experiment which began on the Sloan Telescope in September 2009. I will describe the current status of baryon acoustic oscillation (BAO) results as standard rulers for dark energy, and the design goals of the BOSS experiment. For the five years from 2009-2014, we will map 1.5 million galaxies at z<0.7. A simultaneous survey of 160,000 QSOs will map the hydrogen gas in absorption at redshifts 2.3 < z < 3. BOSS will provide the definitive measurement of the low redshift (z<0.7) BAO scale, and it will pioneer a powerful new method of measuring BAO at high redshift. BigBOSS is a proposed Stage IV experiment that would extend this map to 50 million galaxies over 24,000 deg2. I will describe this survey and its technical status.
(Host: Ge)
November 11, 2009:
Veteran's Day Holiday
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November 18, 2009:
Lincoln Greenhill (CfA)Moving Images of a Massive Young Stellar Object in Formation
Abstract:
The details of how high-mass stars form are not understood. Disk-mediated accretion driven by bipolar outflow is likely. However, the dynamics of material close to high-mass young stellar objects (YSOs), where outflows are launched and collimated, has not previously been resolved in angle. The Kalypso
project has tracked 3-D gas motions in the region 10-1000 AU from a high-mass YSO in the Orion BN/KL region. We resolve disk rotation and wide-angle outflow, narrowing at radii beyond 100 AU, which is consistent with disk mediation. Curved streamlines may indicate for the first time that magnetic fields play a role in launching and shaping outflow for systems with masses of about 8 Msun.
(Host: Jonathan Tan)
November 25, 2009:
Thanksgiving Holiday
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December 2, 2009:
Oleg Kargaltsev (UF)
TBD
Abstract:
(Host: Tan)
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December 9, 2009:
TBD
Abstract:
Logistical Details
Talks are on Wednesday afternoons at 4 p.m. in Florida Gym 260
Refreshments served 30min before talk in Bryant Space Science Center's conference room (215/217)
A campus map is also avaliable online. (Search for BRT to find the Astronomy department, FLG for Florida Gym, PUGH for Pugh Hall).
Other Astronomy Events
Google Calendar of Astronomy Talks
Future Colloquia Dates
Past Colloquia Series
Fall 2008, Spring 2008, Fall 2007, Spring 2007, Fall 2006, Spring 2006, Fall 2005
Colloquium Committee
Reba Bandyopadhyay, Eric Ford, Anthony Gonzalez, Tom Kehoe, Jonathan Tan
Last updated: April 29, 2009
Created: February 25, 2009
