This page lists all of the abstracts for the Fall 2011 colloquium series. For dates and speakers, see Colloquium Spring 2012.
"Observing Love, memory, and spin with gravitational waves", department colloquium, January 23, 2012, 10-11am
Marc Favata, UW-Milwaukee/Caltech
Gravitational-waves are ripples in the curvature of spacetime produced by compact objects (especially neutron stars and black holes) moving at relativistic speeds. In the next 5 years, LIGO (the Laser Interferometer Gravitational-wave Observatory) and its international partners expect to make the first direct detections of these waves (primarily from stellar-mass neutron star or black hole binaries). Future space-based detectors will observe lower-frequency gravitational-waves from supermassive black holes and white dwarfs. Extracting the most science from the expected signals requires detailed modeling of numerous physical effects. After a brief review of general relativity and gravitational waves, I will discuss a few examples of these effects, including: (i) the nonlinear gravitational-wave “memory” in binary black hole mergers, (ii) the tidal “Love number” in binary neutron stars, and (iii) spin interactions in black hole binaries with very small mass ratios.
"Supercomputer simulations of colliding black holes", department colloquium, January 25, 2012, 10-11am
Geoffrey Lovelace, Cornell
Gravitational waves---ripples of spacetime curvature---are poised to open a new window on the universe: the Advanced Laser Interferometer Gravitational-wave Observatory (Advanced LIGO), scheduled for completion in 2015, is expected to detect between 1 and 1000 gravitational waveforms per year. Among the most important sources for Advanced LIGO are colliding black holes, which can radiate as gravitational waves more energy than a supernova. Finding these waves in noisy LIGO data requires accurate predictions of the expected waveforms, but because all analytic approximations break down, the gravitational waves emitted by two colliding black holes can only be predicted using numerical simulations. In this talk, I will discuss recent progress and challenges in supercomputer simulations of colliding black holes and the application of these simulations to LIGO data analysis.
"Searching for gravitational waves from merging neutron stars and black holes", department colloquium January 25, 2012, 10-11am
Chad Hanna, Perimeter Institute
We are entering a new era of experimental gravitational wave physics that should result in the direct detection of gravitational waves later this decade. The global network of laser interferometer gravitational wave detectors including LIGO and Virgo is currently being upgraded to obtain unprecedented sensitivity. It is likely that the first gravitational wave detections will come from merging compact binary systems consisting of neutron stars or black holes. I will give an overview of searches for merging compact binaries and describe what to expect in the next few years. I will emphasize the effort to integrate the gravitational wave astronomy community into the broader time domain astronomy community. We hope that joint work between these communities will help to answer questions about the Universe's most interesting transient phenomena such as short gamma ray bursts.
"Tackling the Challenges of Gravitational-Wave Astronomy", department colloquium January 30, 2012
Kipp Cannon, University of Toronto
Gravitational radiation promises to teach us many new things about the universe and the world around us, but all attempts to observe gravitational waves have so far been unsuccessful. I will discuss some of the challenges
we need to overcome in our quest to detect this elusive form of energy, and how tackling these challenges is driving collaboration between instrument and observational sciences. I will show, specifically, how novel data analysis strategies have been used to combat detector noise in searches for gravitational waves from cosmic strings, and how integrating noise hunting tools directly into search pipelines promises to improve our odds of successfully detecting the collisions of neutron stars and other compact astronomical objects, and open a new window on the universe.
"The dynamic response of merging neutron stars", department colloquium February 1, 2012
Jocelyn Read, University of Mississippi
Neutron stars give us a unique glimpse of physics at extreme scales: the matter in their cores is compressed to densities up to ten times that of an atomic nucleus, in a state fundamentally described by quantum chromodynamics. There is substantial uncertainty about how matter behaves at this density, and astrophysical observations of neutron stars help pin it down.
We should soon be able to observe the gravitational waves radiated by a neutron star is orbiting a black hole or another neutron star. The two objects will spiral towards each other and, eventually, collide. Such events make up a large portion of gravitational-wave sources that Advanced LIGO is expected to observe, and the results of the collision may also explain short gamma-ray bursts that current satellites see.
Details of these signals can tell us about the dense matter that makes up neutron stars, as the matter's properties determine how the neutron star responds to its companion. There are two observational signatures that this talk will cover: First, some gamma-ray flares could be explained by the behaviour of dense matter in the neutron-star crust, as a result of the crust shattering from a resonance with the sweep of tides. Second, contributions to the gravitational-wave signal itself can be seen in from strong tidal deformations as the stars approach each other.
"Electron Impact Ionization Experiments at The University of Manchester", department colloquium, March 23, 2012, 12 noon
Kate Nixon, University of Manchester
Electron collisions resulting in ionization are important in a wide number of areas. These include: the development of lasers, the chemistry of the Earth's upper atmosphere and the treatment of cancers with radiotherapies. The research at University of Manchester has three themes all aimed to further understand these important collisions.
The first theme uses atomic targets. High quality data for electron scattering from atomic targets can be compared to predictions from sophisticated quantum mechanical models. The level of agreement between the experimental and theoretical data shows if the physics of the collisions between electrons and atoms is being modelled accurately. New data has been measured for Ne, Ar, Kr and Xe.
The second research theme is to develop an understanding of electron-molecule collisions. Molecular targets are more complex than atomic target and provide challenges for both experimentalists and theorists. A systematic study of atomic and molecular targets with the same number of electrons has been undertaken using neon, CH4, NH3 and H2O. Comparison of the results for all of these targets highlight which features of the data are due to the electronic structure or the molecular nature of the target.
One of the major challenges for theorists in modelling electron collisions with molecules is how to account for the random orientation of the molecules within typical experiments. The third theme at the University of Manchester is to align the targets before the electron collision. A new experiment is being developed to measured data from aligned H2.
"Exploring the unknown universe with the LHC", department colloquium, April 6, 2012, 12 noon
Daniel Whiteson, UC Irvine
Collisions at the Large Hadron Collider (LHC) let us explore a new territory nearly four times larger than anything previously examined. This energy frontier may be populated with new particles which (1) shed light on the nature of dark matter (2) extend the current table of the fundamental particles (3) demonstrate the existence of new fundamental forces or (4) reveal startling and completely unexpected properties. I will describe a strategy for searching this territory, show the state of the art from the Fermilab Tevatron collider and present recent results from the ATLAS detector at the LHC.
Physics Master's Candidates Projects, department colloquium, April 27, 2012, 12 noon
Dan Henrickson, Chris Griffo, Thomas Abbott, David Green, Khai Nguyen, Josh Tanner, CSU Fullerton
|10'+2||Dan Henrikson||Ionel Tifrea|
|10'+2||Chris Griffo||Searching QUEST Telescope Images for Optical Transients Associated with Gravitational-Wave Triggers||Josh Smith|
|10'+2||Thomas Abbott||Vetoing non-astrophysical transients in LIGO data and characterization of early aLIGO subsystems||Josh Smith|
|10'+2||David Green||Low-energy electron-impact ionization of helium||Greg Childers|
|10'+2||Khai Nguyen||Ionel Tifrea|
|10'+2||Josh Tanner||Morty Khakoo|
"The Uses of Analogy: James Clerk Maxwell’s “On Faraday’s Lines of Force’ and Early Victorian Analogical Argument", department colloquium, May 11, 2012, 12 noon
Kevin Lambert, CSUF Liberal Studies
James Clerk Maxwell’s first paper on electromagnetism is famous for its use of analogy as a means of giving Michael Faraday’s lines of force mathematical form. But early Victorian analogical arguments were also used to order the natural and the social world by maintaining a coherent collective experience across cultural oppositions such as the ideal and material, the sacred and profane, theory and fact. I will argue that Maxwell understood his theoretical work as both a technical practice and as a contribution to an ongoing Victorian conversation about the mid-nineteenth century moral order. Looking at Maxwell’s “On Faraday’s Lines of Force’ in that way provides historical perspective on the development of a new cognitive tool: a way of thinking on paper analogous to thinking with objects in the laboratory.