Francisco-Shu Kitaura

The secrets of dark energy

14 July 2016. Astronomers announced this week the sharpest results yet on the properties of dark energy driving the accelerated expansion of the Universe. For their studies, scientists from the Baryon Oscillation Spectroscopic Survey (BOSS) programme mapped a record-breaking 1.2 million galaxies observed within the Sloan Digital Sky Survey III (SDSS-III). A collection of papers from the BOSS collaboration describing these results was submitted this week to the Monthly Notices of the Royal Astronomical Society. The Leibniz Institute for Astrophysics Potsdam (AIP) has actively participated with important contributions to data analysis and theoretical modelling.

16 February 2016. The BOSS survey has scanned the sky measuring the redshifts of more than 1 million galaxies, yielding a three dimensional picture of luminous sources in our Universe covering about 4.5 billion years. An international team of astronomers has now reproduced the observed galaxy clustering and determined the uncertainties in the measurement of observed quantities by generating thousands of simulated galaxy catalogues. For the first time, the separation between pairs of galaxies, and the separation between triplets of galaxies has been explicitly constrained to reproduce the observations. Hence, the cosmic web in particular the empty regions between galaxies are described.

My work on reconstructions of the initial conditions of the Local Universe lead to the most precise constrained simulations of the Local Universe in collaboration with Steffen Hess. Tom Abel and Ralf Kaehler have done a special visualization showing the filamentary network of the dark matter and in contrast the few luminous tracers made up by galaxies and galaxy clusters. This work appears in the January edition of National Geographic.

In this work we analyzed the dynamics of the Local Universe with a Bayesian machine learning algorithm and made progress in explaining the motion of the Local Group to which our Milky Way belongs. 

I worked on the simulations of core-collapse supernova explosions using hydrodynamics coupled to Boltzman neutrino transport codes to find natural explosions of Crab Nebula like progenitors. 

Left plot: Source: www.spacetelescope.org Credit: NASA, ESA and Allison Loll/Jeff Hester (Arizona State University)  Acknowledgement: Davide De Martin (www.skyfactory.org)