William Atkins
Thursday, 28 August 2008 23:02
Science -
Space
Page 3 of 3
The news release also states,
“The separation between material shown in pink and blue therefore provides observational evidence for dark matter and supports the view that dark matter particles interact with each other only very weakly or not at all, apart from the pull of gravity.”
They conclude in their abstract,
“The total mass distribution in each of the subclusters is clearly offset … from the peak of the hot X-ray emitting gas (the main baryonic component), but aligned with the distribution of galaxies. We measure the fractions of mass in hot gas … and stars …, consistent with those of typical clusters, finding that dark matter is the dominant contributor to the gravitational field.”
And,
“Under the assumption that the subclusters experienced a head-on collision in the plane of the sky, we obtain an order-of-magnitude estimate of the dark matter self-interaction cross-section …, re-affirming the results from the Bullet Cluster on the collisionless nature of dark matter.”