Interaction of clumpy dark matter with interstellar medium in astrophysical systems
Article first published online: 29 NOV 2011
© 2011 The Author Monthly Notices of the Royal Astronomical Society © 2011 RAS
Monthly Notices of the Royal Astronomical Society
Volume 420, Issue 1, pages 590–595, February 2012
How to Cite
Baushev, A. N. (2012), Interaction of clumpy dark matter with interstellar medium in astrophysical systems. Monthly Notices of the Royal Astronomical Society, 420: 590–595. doi: 10.1111/j.1365-2966.2011.20067.x
- Issue published online: 23 JAN 2012
- Article first published online: 29 NOV 2011
- Accepted 2011 October 24. Received 2011 October 20; in original form 2010 November 16
- elementary particles;
- cosmology: theory;
- dark matter
Contemporary cosmological conceptions suggest that the dark matter in haloes of galaxies and galaxy clusters has most likely a clumpy structure. If a stream of gas penetrates through it, a small-scale gravitational field created by the clumps disturbs the flow resulting in momentum exchange between the stream and the dark matter. In this article, we perform an analysis of this effect, based on the hierarchical halo model of the dark matter structure and Navarro–Frenk–White density profiles. We consider the clumps of various masses, from the smallest up to the highest ones M≥ 109 M⊙. It has been found that in any event the effect grows with the mass of the clump: not only the drag force acting on the clump but also its acceleration increases.
We discuss various astrophysical systems. The mechanism proved to be ineffective in the case of galaxy or galaxy cluster collisions. On the other hand, it played an important role during the process of galaxy formation. As a result, the dark matter should have formed a more compact, oblate and faster rotating substructure in the halo of our Galaxy. We have shown that this thick disc should be more clumpy than the halo. This fact is very important for the indirect detection experiments since it is the clumps that give the main contribution to the annihilation signal. Our calculations show that the mechanism of momentum exchange between the dark and baryon matter is ineffective on the outskirts of the galactic halo. It means that the clumps from there were not transported to the thick disc, and this region should be more clumpy than the halo on the average.