Image Credit: ESO/M. Kornmesser
Our research focuses on the study of the intergalactic medium using quasar spectroscopy. This field of research is commonly known as observational cosmology and consists of studying the origin, structure and evolution of the Universe through astronomical observations.
Quasars are among the brightest and most distant objects in the Universe. When a photon produced by a distant quasar reaches a telescope on Earth, it carries with it all the information from the part of the Universe it crossed. This information can be identified and extracted by fitting the absorption features imprinted onto the quasar spectrum.
Any absorption line in a quasar spectrum is a direct signature of a gas cloud present in the intergalatic medium and can be approximated by a mathematical function called a Voigt profile. From such profile, one can gain insight into the kinematics of the atoms in the cloud as well as the local temperature and density of atoms present in that cloud.
The knowledge we get from fitting absorption line features can be used to probe the evolution of the fundamental laws of physics throughout the Universe, that is throughout cosmological time from the Big Bang until now. In the next section, we present our 3 main projects.
Deuterium is the second lightest element in the Universe and was produced during the very first minutes after the Big Bang in the epoch known as Big Bang Nucleosynthesis (BBN). The current standard BBN theory predicts that the primordial abundances of very light nuclei can be directly related to the mean cosmological baryon density parameter. The Deuterium-to-Hydrogen ratio can be directly measured in quasar spectrum by identifying and fitting both HI and DI absorption lines. The ratio of the extracted column densities will provide a direct estimate of the total density of baryonic matter in the Universe.
"The primordial deuterium abundance at z=2.504 from a high signal-to-noise spectrum of Q1009+2956", E. O. Zavarygin et al.
Short description missing.
"Probing the Gravitational Dependence of the Fine-Structure Constant from Observations of White Dwarf Stars", M. B. Bainbridge et al.
Short description missing.
"Modelling long-range wavelength distortions in quasar absorption echelle spectra", V. Dumont & J. K. Webb
Astrophysics Professor
@ University of New South Wales
@ DAMTP, Cambridge University
Research Associate
@ UC Berkeley
@ University of New South Wales
Research Associate
@ University of Oslo
PhD Student
@ University of New South Wales
PhD Student
@ University of New South Wales
PhD Student
@ University of New South Wales
Research Associate
@ University of Leicester
PhD Student
@ European Southern Observatory
Physics Professor
@ University of New South Wales
@ Helmholtz Institute Mainz
Any spectroscopic data used in our research have been reduced and thoroughly cleaned by members of our team or external collaborators. All the product files from the data reduction and cleaning process are made entirely available to help other scientist to review our research objectively.
Feel free to contact us if you are either interested to join our group or simply want to know more about our research.
The University of California at Berkeley
The University of New South Wales
Cambridge University
The University of Oslo