KIPMU: The Gravitational Evolution of Dark Matter Halos

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KIPMU: The Gravitational Evolution of Dark Matter Halos

Post by bystander » Tue Jan 13, 2015 4:34 pm

Decoding the Gravitational Evolution of Dark Matter Halos
Kavli Institute for the Physics and Mathematics of the Universe | 2015 Jan 13

Researchers at Kavli IPMU and their collaborators have revealed that considering environmental effects such as a gravitational tidal force spread over a scale much larger than a galaxy cluster is indispensable to explain the distribution and evolution of dark matter halos around galaxies. A detailed comparison between theory and simulations made this work possible. The results of this study ... contribute to a better understanding of fundamental physics of the universe.

In the standard scenario for the formation of a cosmic structure, dark matter, which has an energy budget in the universe that is approximately five times greater than ordinary matter (e.g., atoms), first gathers gravitationally to form a crowded region, the so-called dark matter halos. Then these dark matter halos attract atomic gas and eventually form stars and galaxies. Hence, to extract cosmological information from a three-dimensional galaxy map observed in SDSS BOSS, the SuMIRe project, etc., it is important to understand how clustering of dark matter halos has gravitationally evolved throughout cosmic history. (This is referred to as the halo bias problem.) ...

“The results of our study allow the distribution of dark matter halos to be more accurately predicted by properly taking into account higher-order terms missed in the literature,” said Shun Saito ... “Our refined model has been already applied to actual data analysis in the BOSS project. This study certainly improves the measurement of the nature of dark energy or neutrino masses. Hence, it has led to a better understanding of the fundamental physics of the universe.”

Understanding higher-order nonlocal halo bias at large scales by combining the power spectrum with the bispectrum - Shun Saito et al
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