Paper: astro-ph/0512494
Date: Tue, 20 Dec 2005 05:44:44 GMT (8kb)

Title: An alternative to dark matter: do braneworld effects hold the key?

Authors: Supratik Pal (IIT Kharagpur & Jadavpur University)

Comments: 9 pages, 2nd prize winning paper presented at XXIII Young Physicists'
Colloquium of the IPS, to appear in The Physics Teacher
\\
An alternative way of explaining astrophysical observations without dark
matter is proposed. In the braneworld scenario, where our universe is
visualised as a 4-dimensional hypersurface embedded in a higher dimensional
spacetime, the effective Einstein equation on the brane contains extra terms.
We show that the astrophysical observations which are usually explained by
particle dark matter, can be explained in this modified theory of gravity via
those extra terms, without the need for dark matter. As specific example, we
model X-ray profiles of clusters of galaxies and the galaxy rotation curves
which are consistent with observations. Further, we investigate whether
gravitational lensing can discriminate between the two possibilities.
Significant differences between the values of the deflection angles are
obtained, which can be tested in future observations.

\\ ( http://arXiv.org/abs/astro-ph/0512494 , 8kb)