Central European Institute for Cosmology and Fundamental Physics

Upcoming seminars

15 May 2018, 15:00    Santiago Casas,  Model-independent tests of gravity with present data and future surveys


17 May 2018, 16:00    Lorenzo Pizzuti,  Modified gravity with galaxy cluster mass profiles: from data to simulations


21 May 2018, 14:00    Maksym Ovchinnokov,  New physics at the intensity frontier




15/05/2018 -- Santiago Casas (CEA Paris-Saclay)

Time:  15:00

Place: 117

The large freedom in the free functions affecting linear perturbations in theories of modified gravity and dark energy leads to the burden of parametrization, which means that the observational constraints depend strongly on the way these free functions are parametrized. Using a model-independent test of gravity, alleviates this problem and it even frees us from assumptions about initial conditions, galaxy bias or the nature of dark matter. In this talk I will present the first model-independent reconstruction of the gravitational slip as a function of redshift, using present data on large scale structure and the Hubble function. For future data I will show how we can use these tests to rule out entire classes of modified gravity models and how we have to handle, in a Bayesian way, the constraints from models which are very close to LCDM and might not even be clearly distinguishable, even with next generation surveys.



17/05/2018 -- Lorenzo Pizzuti (Trieste)

Time:  16:00

Place: 226

I will provide a brief overview on my work concerning constraints on modified gravity models obtained using galaxy cluster mass profile determinations. In particular, I will present the results of a paper in which we combined the information given by the kinematic of galaxies in cluster with the information provided by lensing analyses for 2 galaxy clusters of the CLASH-CLASH\VLT collaboration to get constraints on f(R) models. In order to discuss the applicability of the proposed method in view of future imaging and spectroscopic surveys, I will further introduce my current study of cosmological simulations, aiming at estimating and calibrating the impact of systematics.



21/05/2018 -- Maksym Ovchinnokov (Leiden University)

Time:  14:00

Place: 226

It is well-known that the Standard Model of particle physics does not explain dark matter, neutrino masses and matter-antimatter asymmetry of the Universe and therefore has to be extended. This means that there should exist some new particles that are either too heavy to be found before (the “energy frontier”) or interact too feebly (the “intensity frontier”). In the absence of a good guiding principle predicting where we should look for new physics, we consider the so-called “portals” — renormalizable interactions between new particles and the Standard Model. We review these portals and their phenomenology at the “intensity frontier” (in particular at SHiP). We pay special attention to the searches of dark matter particle through these portals and discuss the cosmological status of “light dark matter”.