The beautiful data on the large-scale structure of the universe
revealed in particular by the 2dF Galaxy Redshift Survey
combine with the incredible recent progress in CMB
data to show spectacularly good agreement with a
`standard model' for structure formation. This consists
of a scalar-mode adiabatic CDM universe with scale-invariant
fluctuations. Measuring the exact parameters of this
model is rendered difficult by the intrinsic degeneracies
of the structure-formation process, but progress is
being made. The most recent data yield
m =
0.25± 15% and h = 0.73 ± 5%; these
figures accord well with independent constraints, and it
is very hard to believe that they are incorrect.
Allowing extra degrees of freedom, such as massive neutrinos,
vacuum equation of state w
1, or extra relativistic
content worsens the agreement with independent constraints on
h and
m. This
both supports the simplest picture and allows us to set interesting
limits on these non-standard ingredients.
For the future, we can look with anticipation to
meaningful tests of inflation: the current data are consistent
with n = 1 to an error of ± 0.03, and the errors may be
expected to halve over the next couple of years, bringing
plausible levels of tilt well within the reach of
experimental detection. A demonstration that n
1 would be a large step in the direction of proving inflation to be
true, so the cosmological stakes over the next few years will be high.
The tensor fraction is a less clear target, but the motivation
to improve on the current weak upper limits will remain strong.
It should of course not be forgotten that the large-scale structure we measure locally consists of galaxies. In these lectures, the physics of galaxy formation has been largely ignored, but this will be the increasing focus of LSS studies: not just the global parameters of the universe, but the detailed understanding of how the complex structures around us formed.
Acknowledgements
I have drawn on the body of results achieved by my colleagues in the 2dF Galaxy Redshift Survey team: Matthew Colless (ANU), Ivan Baldry (JHU), Carlton Baugh (Durham), Joss Bland-Hawthorn (AAO), Terry Bridges (AAO), Russell Cannon (AAO), Shaun Cole (Durham), Chris Collins (LJMU), Warrick Couch (UNSW), Gavin Dalton (Oxford), Roberto De Propris (UNSW), Simon Driver (St Andrews), George Efstathiou (IoA), Richard Ellis (Caltech), Carlos Frenk (Durham), Karl Glazebrook (JHU), Carole Jackson (ANU), Ofer Lahav (IoA), Ian Lewis (AAO), Stuart Lumsden (Leeds), Steve Maddox (Nottingham), Darren Madgwick (IoA), Peder Norberg (Durham), Will Percival (ROE), Bruce Peterson (ANU), Will Sutherland (ROE), Keith Taylor (Caltech). The 2dF Galaxy Redshift Survey was made possible by the dedicated efforts of the staff of the Anglo-Australian Observatory, both in creating the 2dF instrument, and in supporting it on the telescope.