Astrophysics Science Division Colloquium Series
Schedule: Fall 2010

Astrophysics Science Division Colloquium Series
Schedule: Fall 2010

Through the courtesy of the speakers since 2004, some presentations are available on line.

Recent schedules:

  • 2010, Spring
  • 2009, Fall
  • 2008, Spring
  • 2008, Fall
  • 2008, Second Quarter
  • 2008, First Quarter

    ASD Colloquia are Tuesdays at 3:45 pm (Meet the Speaker at 3:30 pm)
    in Bldg 34, Room W150 unless otherwise noted.


    Sep 21 David Bennett (Notre Dame) - The Microlensing Planet Search Program of the WFIRST Mission
    Host: Aki Roberge
    Sep 28 Andy Gould (Ohio State)- Toward a New Era in Planetary Microlensing


    Oct 5 Alan Boss (Carnegie) - Who Pulled the Trigger: A Supernova or an AGB Star?
    Oct 12 Matt Mewes (Swarthmore) - Astrophysical tests of Lorentz and CPT Violations
    Oct 19 Martin Still (Ames) - Astrophysics with Kepler
    Oct 26 Kelly Holley-Bockelmann (Vanderbilt) - Supermassive Black Holes from Seeds: The Nbody Perspective
    Host: John Baker


    Nov 2 Adam Burrows (Princeton) - Attempting to Match Theory with Exoplanet Observation: A Report from the Front Lines
    Nov 9 Marco Chiaberge (STScI) - Low luminosity radio galaxies at high redshifts: beacons for clusters of galaxies?
    Nov 16 Daniela Calzetti (UMass) - The quest for SFR measurements from the UV to the Infrared
    Nov 30 John Beacom (Ohio State) - MeV neutrino and Gamma-ray emission from massive stars


    Dec 7 Andrea Ghez (UCLA) - TBD
    Dec 14 Nathan Smith (U Arizona) - TBD

    The Microlensing Planet Search Program of the WFIRST Mission

    David Bennett

    Notre Dame

    Tuesday, September 21, 2010


    The recently Decadal Survey report, "New Worlds, New Horizons in Astronomy and Astrophysics" recommends a new mission called WFIRST as its top ranked large space mission for the next decade. The WFIRST mission is to have two major science programs that will drive the design requirements: a dark energy program and a microlensing planet search program. WFIRST's microlensing planet search program will provide a statistical census of exoplanets with masses greater than one tenth of an Earth mass and orbital separations ranging from 0.5AU to infinity. This includes analogs to all the Solar System's planets except for Mercury, as well as most types of planets predicted by planet formation theories. In combination with Kepler's census of planets in shorter period orbits, WFIRST's planet search program will provide a complete statistical census of the planets that populate our Galaxy.


    Toward a New Era in Planetary Microlensing

    Andy Gould

    Ohio State

    Tuesday, September 21, 2010


    Microlensing planet searches are rapidly advancing in several dimensions. Originally it was believed that microlensing lightcurves would yield only a few dimensionless parameters, like the planet-star mass ratio. Now, several planetary events have host masses and distances. Incredibly, at least one microlensing planet seems likely to yield a complete 8-parameter Kepler solution. We are beginning to probe the Galactic distribution of planets, with a strong suggestion that planets are more common in the disk than the bulge. The field as a whole is beginning to transition from survey+followup to pure-survey mode, with huge implications for the planet detection rate, the type of information extracted from individual events, and the level of statistical analysis that can be applied to the ensemble of detections. Microlensing planet searches from space, which received the highest-priority recommendation of the Decadal, will further transform the field.


    1973-80 auto assembly worker, Ford Motor Co.
    1981-83 actuary, Wm M Mercer, co.
    1984-88 Stanford Physics dept PHD
    1988-93 IAS, postdoc
    1993-2010 OSU Astronomy dept: asst, assoc, full professor.
         University Distinguished Scholar
         Distinguished Professor of Mathematical & Physical Sciences
         Thomas Jefferson Professor for Discovery and Space Exploration

    Main fields of work:
    Gravitational microlensing
    Galactic Structure

    Who Pulled the Trigger: a Supernova or an AGB Star?

    Alan Boss


    Tuesday, October 5, 2010


    The short-lived radioisotope 60Fe requires production in a core collapse supernova or AGB star immediately before its incorporation into the earliest solar system solids. Shock waves from a somewhat distant supernova, or a relatively nearby AGB star, have the right speeds to simultaneously trigger the collapse of a dense molecular cloud core and to inject shock wave material into the resulting protostar. Adaptive mesh refinement hydrodynamical models shows that the injection efficiency depends sensitively on the assumed shock thickness and density. Supernova shock waves appear to be thin enough to inject the amount of shock wave material necessary to match the short-lived radioisotope abundances measured for primitive meteorites. Planetary nebula shock waves from AGB stars, however, appear to be too thick to achieve the required injection efficiencies. These models imply that a supernova pulled the trigger that led to the formation of our solar system.


    Alan Boss is a research staff member at the Carnegie Institution's Department of Terrestrial Magnetism in northwest Washington, D.C. Boss received his Ph.D. in physics from the University of California, Santa Barbara, in 1979. He spent two years as a postdoctoral fellow at NASA's Ames Research Center in California before joining the staff of DTM in 1981. Boss's theoretical research focuses on using three dimensional hydrodynamics codes to model the formation of stars and planetary systems. Boss has proposed an alternative means for forming the gas and ice giant planets of our Solar System and in extrasolar planetary systems, a scenario that is much faster than the conventional mechanism. He is a member of the American Academy of Arts and Sciences, and is a Fellow of the American Association for the Advancement of Science (AAAS), the Meteoritical Society, and the American Geophysical Union. Boss was the founding chair of the International Astronomical Union's Working Group on Extrasolar Planets. He has been helping NASA plan its search for extrasolar planets since 1988 and continues to be active in helping to guide NASA's efforts. Boss leads a ground-based astrometric planet search effort at Carnegie's Las Campanas Observatory in Chile. He has published two books about the search for planets outside the Solar System, "Looking for Earths: The Race to Find New Solar Systems" in 1998, and "The Crowded Universe: The Search for Living Planets" in 2009. He is currently the President of IAU Commission 53 on Extrasolar Planets, Chair of the Astronomy Section of the AAAS, and Chair of the Astrophysics Subcommittee of the NASA Advisory Council. He also serves on NASA's Exoplanet Technology Assessment Committee and on the Science Working Group for NASA's Kepler Mission.

    Astrophysical tests of Lorentz and CPT Violations

    Matthew Mewes


    Tuesday, October 12, 2010


    Lorentz invariance lies at the foundations of all known physics. However, attempts at quantum gravity suggest that this symmetry may not be exact at energies below the Planck scale. This idea has spurred a variety of theoretical and experimental studies of Lorentz invariance. Over the past decade, searches for violations of Lorentz symmetry and the related CPT symmetry have been performed in numerous systems. Some of the best constraints on Lorentz and CPT violation have been obtained by examining the properties of light from sources at cosmological distances. In particular, searches for vacuum dispersion and birefringence in light from sources such as gamma-ray bursts provide a highly sensitive probe of Lorentz invariance. In this talk, I will discuss recent work that characterizes general Lorentz violations in electromagnetism and the effects of these violations on light propagating through empty space.


    2004: PhD, Indiana University
    2004-2005: Assistant Professor, Carleton College, Northfield, MN
    2005-2009: Assistant Professor, Marquette University, Milwaukee, WI
    2009-present: Assistant Professor, Swarthmore College, Swarthmore, PA

    Astrophysics with Kepler

    Martin Still


    Tuesday, October 19, 2010


    Kepler is a NASA Discovery mission to identify and characterize Earth-sized planets within the habitable zone around Solar-like stars. The Kepler instrument also provides an unprecedented opportunity to test and refine a diverse range of astrophysical paradigms with high-precision, uniform and rapid cadence data, containing none of the diurnal or seasons gaps that limit ground-based observations. In this talk I will present the Kepler mission, it's archive and Guest Observer program, and provide scientific highlights of the early astrophysics programs conducted though proposed target observations and archive exploitation.


    Martin is the Guest Observer Office Director and Science Office Deputy-Director for the Kepler mission, run from the NASA Ames Research Center, CA.

    Supermassive Black Holes from Seeds: The Nbody Perspective

    Kelly Holley-Bockelmann

    Tuesday, October 26, 2010


    Supermassive black holes are a natural part of nearly every galaxy, but how they form, grow, and interact within the galactic center is still a mystery. In this talk, we will explore how the cosmological environment can support or suppress a seed black hole's growth into a supermassive one. We will review what is known about how, and how often, black holes merge as they grow, and we will present new results of the unexpected ways in which subtle changes in the black hole's environment can affect the black hole's growth.


    Attempting to Match Theory with Exoplanet Observation: A Report from the Front Lines

    Adam Burrows


    Tuesday, November 2, 2010


    Approximately 500 exoplanets, mostly giant planets in the Jovian mass range, but also more than 70 "Neptune-mass" planets and a handful of "super-Earths," have been detected orbiting stars in the solar neighborhood. More than 15% of these are transiting their primaries and these have collectively yielded a wealth of structural and physical information. A number of these exoplanets have recently been detected in secondary eclipse and primary transit by the Spitzer infrared space telescope, NICMOS on HST, Kepler, CoRoT, MOST, and EPOXI. These constitute precious remote-sensing data of extrasolar worlds, and JWST stands in the wings to push this science to the next level. I will present the embryonic theory of irradiated giant planets and discuss what we have learned about their atmospheres, radii, and compositions. I will also address what we may soon learn from the variety of ground-based and space-based telescopes being planned or already under development as the exploding field of exoplanets accelerates into its future.


    Low luminosity radio galaxies at high redshifts: beacons for clusters of galaxies?

    Marco Chiaberge


    Tuesday, November 9, 2010


    Low luminosity radio galaxies, most of them showing a Fanaroff-Riley I (FRI) radio morphology, are an interesting class of AGN. In the past, we studied in detail the properties of these objects in low redshift samples. Recently, we turned our attention to the distant universe, and we selected a new sample of "candidate FRIs" between z~1 and z~2 in the COSMOS field with the aim of studying, for the first time, the properties of these sources at high-z. An important aspect of this research concerns the study of the environment of these sources. In fact we know that, differently from the more powerful FRIIs, FRIs almost exclusively reside in clusters of galaxies, at least at low redshifts. In this talk I will outline interesting properties of low luminosity radio galaxies at low and high redshifts, and I will show that these objects can be used (more effectively than using FRIIs) to find clusters of galaxies in the substantially unexplored range of redshift 1.5


    I got my PhD at SISSA in Trieste, Italy, in 2000 with a thesis on "The HST view of the nuclei of radio galaxies" and its implications for the AGN unification scheme (Advisors: Dr. Alessandro Capetti and Dr. Annalisa Celotti). Then I moved to STScI for a 2 year postdoc with Dr. Macchetto and Dr. Sparks, still working on low redshift radio galaxies with HST.

    In 2002 I got a permanent research position at the Institute of Radio Astronomy in Bologna, Italy (from which I am on a leave of absence) and in 2005 I came back to STScI as an ESA astronomer, working in the Advanced Camera for Surveys instrument team.

    My research interests are mainly on AGNs (mainly from the observational point of view), and in particular on radio galaxies, Seyfert galaxies, blazars, but I also work on the properties of accretion onto supermassive black holes and its relationship with the AGN phenomenology.

    The quest for SFR measurements from the UV to the Infrared

    Daniela Calzetti


    Tuesday, November 16, 2010


    Nearby galaxies are the benchmark against which we compare the properties of distant galaxies and the best laboratory for learning about the physics of star formation and the gas-stars cycling. Star formation is the prime mechanism driving the evolution of the luminous component of galaxies across cosmic times, yet much of the underlying physics governing it is poorly understood. One of the current problems is understanding how to measure star formation rates on sub-galactic scales. I review the current issues, covering from the UV to the infrared, including recent progress enabled by the Spitzer Space Telescope, by the GALEX mission; I will also present some preliminary results from the Herschel Space Telescope. I will place these results in the context of future developments in the field, where the exploitation of existing and new/future facilities like HST, JWST, the Large Millimeter Telescope and ALMA, will be key to address some of the extant issues.


    PhD: 1992 at the University of Rome
    Employment: Postdoc at STScI, 1992-1995
         Assistant and then Associate Astronomer, STScI, 1995-2006
         Associate and then full Professor (since 2009), UMass,2007-present
    Expertise/experience: star formation in nearby galaxies, effects of dust
         obscuration, properties of dust emission.

    Stefan Immler
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