We just submitted a paper where we probe a modified gravity model

with the help of Supernova observations [astro-ph/0510453].

This was a numerical Tour de Force, since the equations which usually

govern the dynamical evolution of the Universe and are usually very

simple to solve turn into highly non-trivial, non-linear higher order

differential equations. It took as about four month to come up with a

satisfactory solution. But the work is already sparking some interest

in the community. We have basically shown that you can restrict the

free parameters appearing in these models with observations of distant

Supernovae and the expansion rate of the Universe.

What is the possible consequence of these models ?

Well essentially the outcome is that we do NOT need a dark energy

component. We just have to modify gravity in an appropriate way

[see my previous blog]. And the interesting thing is, it really works.

Unfortunately we could not push these models so far to also get rid of

dark matter, but we are currently thinking about this :).

Of course there is a plethora of other cosmological probes like the cosmic

microwave background, clusters of galaxies and large scale structure.

However since we work in a modified gravity background we have to

carefully recalculate all the theoretical assumptions made for these

probes, in order to make sure that we pick up any possible new effects

emerging in modified gravity scenarios. This is a very hard task, but it

is fun.

Here is a nice picture about the constraints derived in the paper

you could actually vanish strange loops by minimizing recombination. here:

lys-arg-ile-asp

i derived this in my life as a frog... (BBN-425)

Posted by: m.visaya | October 24, 2005 at 10:20 AM

the sky stopped falling today.

Posted by: m.visaya | November 22, 2005 at 03:05 PM