Research Events
For the Public
Northwestern University

Weekly Astrophysics Seminars 2014-2015

Seminars are held at 4:00 PM on Tuesdays in Room F160
on the first floor of the Technological Institute (2145 Sheridan Road) unless otherwise noted


Spring Quarter 2015

  Date      Speaker / Seminar Host
  March 31

Marilena LoVerde
   The University of Chicago
    Cosmic Neutrinos and Large-scale Structure

Cosmic background neutrinos are nearly as abundant as cosmic microwave background photons, but their mass, which determines the strength of their gravitational clustering, is unknown. Neutrino oscillation data gives a strict lower limit on neutrino mass, while cosmological datasets provide the most stringent upper limit. Even if the neutrino masses are the minimum required by oscillation data, their gravitational effects on structure formation will nevertheless be detectable in -- and in fact required to explain -- data within the next decade. I will discuss the physical effects of the cosmic neutrino background on structure formation and present a new signature that may be used to measure neutrino mass with large galaxy surveys.


  April 7

Dawn Erb
   University of Wisconsin, Milwaukee
    Feedback in Faint Galaxies at the Peak Epoch of Star Formation

Because faint, low mass galaxies are numerous at high redshifts, their impact on the Universe is expected to be significant. They may host a substantial fraction of global star formation, provide many of the energetic photons needed to reionize the universe, and contribute to the enrichment of the intergalactic medium through the expulsion of metals in galactic outflows. Because of their faintness, however, the properties of these galaxies are difficult to determine. I will discuss a variety of observations aimed at characterizing the physical conditions in low mass galaxies at redshifts z~2-3, the peak epoch of star formation in the Universe, with particular emphasis on the study of galactic outflows in faint galaxies.

Daniel Angles-Alcazar

  April 21

Geoffrey Vasil
   The University of Sydney


  April 28

Tony Piro
   Carnegie Institute for Science

Francesca Valsecchi

  May 7
  Tech F160

Phil Muirhead
   Boston University
    Small Stars with Small Planets and Big Consequences

The field of extrasolar planets is rapidly evolving. The quest to discover ever more and ever smaller exoplanets has pushed the field in two primary directions: (1) toward a comprehensive assessment of the frequency and statistics of various types of exoplanets -- used to constrain planet formation and evolution theories -- and (2) toward characterizing the composition, atmosphere, and evolution of individual exoplanets as though they were planets in our own Solar System. I will discuss the importance of low-mass stars in this context, emphasizing the phenomenal results from the NASA Kepler Mission, and our efforts to characterize individual terrestrial exoplanets orbiting low-mass stars with existing and new ground-based instrumentation.

Jason Steffen

  May 19

Edwin Bergin
   University of Michigan
    Dissecting the Explosions and Environments of Nearby Supernovae

Evidence has mounted that Type Ia and core-collapse (CC) supernovae (SNe) can have substantial deviations from spherical symmetry; one such piece of evidence is the complex morphologies of supernova remnants (SNRs). In this talk, I will highlight techniques we have developed to ascertain the role of explosion geometry and environment in shaping these SNRs. I will discuss application of these methods to extensive multiwavelength data of Milky Way and Magellanic Cloud SNRs, and I will explore the implications regarding the nature of the progenitors and the dynamical evolution of these sources.

Farhad Zadeh

  May 26

Tom Abel
   Stanford University
    Dark Matter Dynamics

Computational Physics allows us to study extremely non-linear systems with fidelity. In astrophysical hydrodynamics and studies of galaxy formation much of the last two decades we have explored various discretization techniques and found subtle differences in some applications. Interestingly numerical studies of collisionless fluids such as e.g. the collapse of cold dark matter to form the large scale structure of the Universe has only been studied meaningfully with one approach; N-body Monte Carlo techniques. I will introduce a novel simulation approach, and demonstrate its feasibility, that for the first time can study a collisionless system in the continuum limit in multi-dimensions. I will also show this new technique opens a new window in making sense of structure formation as well as plasma physics. In this context we have developed a novel rasterization/voxelization algorithm applicable in computational geometry, computational physics, CAD design and other fields. I show how these approaches allow also for much improved predictions for gravitational lensing, dark matter annihilation, properties of cosmic velocity fields , and many other applications.

Fred Rasio

  June 2

Garth Illingworth
   UC Santa Cruz

Mel Ulmer

Fall Quarter 2015

  Date      Speaker / Seminar Host
  Oct. 20

Laura Chomiuk
   Michigan State University

Fred Rasio

For more information, contact: ciera@northwestern.edu

Past Astrophysics Seminars