Seminar iz fizike

Četvrtak 21. maj 2015. u 13:00 u učionici 62, Departman za fiziku


Zarija Lukić, Lawrence Berkeley National Laboratory:

Studying the evolution of the Universe with quasar spectra + Identifying materials using cosmic rays, and the application on damaged cores at Fukushima power plant.


The Lyman-alpha forest in spectra of distant quasars is the main tracer of cosmological structure at high redshifts, 2<z<5, and is accessible to current (BOSS/eBOSS) and future (DESI) spectroscopic sky surveys.  On large-scales, the Ly-a power spectrum can be used as a standard ruler, measuring the scale of Baryon acoustic oscillations (BAO).  On small-scales, the Ly-a forest enables constraining neutrino masses, and more generally opens an additional window into the nature of dark matter.  Extracting precision cosmology information from the forest statistics amounts to solving inverse problem, i.e. running accurate simulations for a large number of different cosmologies, which are to be compared against the observations.  Besides presenting latest BOSS results, I will also go over a number of topics relevant for modeling forest statistics, both numerical – like the resolution or the box-size – as well as physical ones, like our understanding of the UV background.  Finally, I will briefly present the Nyx code we have build to efficiently run Lyman-alpha forest simulations on massively parallel computers.

In addition, a separate topic on identifying materials using cosmic rays and its application on damaged cores at Fukushima power plant will also be discussed.