Talks

There is now a consensus that gamma-ray bursts involve extraordinary power outputs, and highly relativistic dynamics. The trigger is probably a binary merger or collapse involving compact objects. The most plausible progenitors, ranging from NS-NS mergers to various hypernova-like scenarios, eventually lead to the formation of a black hole with a debris torus around it. The various modes of energy extraction from such systems are discussed.

Assuming that you are really (really) strong, what are the biggest objects in the Universe that hold together enough that you could throw them? What are they made of and why are they so big? In this talk, I will show how studies of the large scale structure of the Universe enable us to reconstruct the initial conditions at the Big-Bang and test the fundamental laws of physics. Among other things, scientist are trying to test one of the most provocative idea of modern physics: the possibility that these huge "things" actually originated from quantum fluctuations smaller than anything we have ever detected!

What is the Universe made of? Recent observations suggest surprising results: not only most of the matter in the Universe is dark and unconventional but, more surprisingly, the major component of the Universe may be in the form of 'dark energy' -- a form of energy that opposes the pull of gravity and causes the expansion of the universe to accelerate. By combining recent observations of clusters of galaxies, distant supernovae, and the cosmic microwave background, we find evidence for a Universe that has only 5% 'normal' baryonic matter, 20% non-baryonic dark matter, and 75% 'dark energy'. The observations suggest a Universe that is lightweight, with only 25% of the critical mass-density needed to halt the Universal expansion, and a geometry that is flat with no space curvature. The observations of the dark side of the Universe and their implications will be discussed.

In recent years there has been an increase in the number of women in all academic levels in physical and applied sciences in Canada. Despite the modern feminist movement the number of women in physics continues to be less than the number of men, particularly in higher and leadership positions. As there is no rational reason for women to trail men in achieving new scientific discoveries or excel in academic teaching, the cause of this is attributed to existing gender biases in the perception and practice of science. Thus increasing the number of women in physics as well as emphasising their relevance in physics has emerged as a women

Today there is robust observational evidence of dark and compact objects in X-ray binary systems with a mass of 5-20 $M_\odot$ and in galactic nuclei with a mass of $10^5 - 10^9$ $M_\odot$. The conjecture is that all these objects are the Kerr black holes predicted by General Relativity, as they cannot be explained otherwise without introducing new physics. However, there are no directs observational evidences. In this talk, I discuss how the Kerr black hole hypothesis can be tested with present and future X-ray data and the current constraints on the nature of this objects.

Molecular spectroscopy offers the tools and instrumentation needed to unveil the structure and characteristics of molecules that are found within planetary atmospheres. In order to do this we examine the frequencies of light that these molecules either absorb or emit. It is the fine structure of these absorption or emission features that give us information about their physical state.. In our lab we use a near-infrared source to probe various molecules and examine absorption features and their dependency on both temperature and pressure. In this study we plan to retrieve the N2-broadened widths, pressure-induces N2-shifts and N2-broadened line mixing coefficients for twenty two transitions in the P branch of the ν1+ν3 band of acetylene mixed with nitrogen. The gas mixture has been selected to be 10% acetylene and 90 % nitrogen. We will record spectra using a 3 channel tuneable diode laser spectrometer. The system contains a temperature controlled single pass absorption gas cell of fixed length, a room temperature cell filled with pure acetylene gas used to create a reference spectra and a third background cell. The system is controlled by LabVIEW software which will be discussed.Simulations have been performed on the v1+v3 band using data obtained from the HITRAN database and will be presented. . From the simulations we determined that we can measure twenty two lines in the P-branch of this band. These lines are all within the interval of P(1)-P(31). For each line we will record spectra at pressures of 100, 250, 400 and 500 torr and for each pressure we plan on measuring 7 different temperatures ranging from -60 to 60C. From these recorded spectra we hope to obtain line parameters using a nonlinear least squares fitting routine. The routine will allow for use of several different line shape models. This study will be the first one over a range of temperatures.