student Michael Murphy presenting the results of this
research into the fine-structure constant.
Searches for temporal or spatial variations in the fundamental
constants is presently an area of intense activity. A major
goal for 2002 was to rigorously test our early results using
a large sample of Keck spectra obtained by Prof. W. Sargent
and his collaborators. We have now analysed about 100 high
resolution Keck quasar spectra. These new results have now
been reported in the literature. To our surprise, the new
data are also consistent with a fine-structure constant, alpha,
which is slightly smaller than the present day value. The
statistical significance of the effect is high (about 6 sigma).
Extensive statistical tests to try and identify systematic
effects which could emulate a varying alpha have also been
carried out but none have so far been found.
The project proved to be a very successful training ground
for Michael Murphy, who completed his PhD at UNSW at the end
of 2002 and has now moved to a postdoctoral appointment at
the Institute of Astronomy in Cambridge.
A new postdoctoral research assistant, Dr. Panyayiotis Tzanivaris,
who recently completed his PhD at the Cambridge IoA, has been
appointed at UNSW to work on the ESO archive of quasar spectra
obtained using UVES on the VLT.In parallel with the work on
optical quasar spectra described above, Dr. Stephen Curran
has been pursuing a different approach, developing radio astronomy
methods to search for variations in a combination of constants,
including alpha, gp (the proton g-factor), and
me/mp, the ratio of the electron and
In collaboration with Victor Flambaum and Vladimir Dmitriev,
and my PhD student, Gabriel Mititelu, a new area has also
arisen during the past year: using the light element abundances
and theory to ask whether the deuteron binding strength Q
was different at the time of Big Bang nucleosynthesis (BBN).
We seem to have an astonishing new result: a slightly smaller
value of Q at the epoch of BBN simultaneously reconciles 4He,
7Li and D observed abundances (which are otherwise
discrepant), and renders agreement between the baryonic density
parameters determined independently by BBN and the latest
results from CMB measurements. This could be a coincidence,
but it is a remarkable one if so.