Wednesday Colloquium

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27.09.2017
"Gravitational Wave Detection and Parameter Estimation"

Matthew Benacquista (University of Texas)

In light of the recent detections of gravitational waves from binary black holes with LIGO/Virgo, I will discuss the physics of the generation, propagation, and detection of gravitational waves with an emphasis on parameter estimation. In particular, I will highlight the uncertainties and selection effects in the observations and the limitations in determining the origin of these sources.


04.10.2017
"Testing General Relativity with gravitational waves"

Michał Bejger (NCAC, Warsaw)


11.10.2017
"TBA"

Michael Fellhauer (Departamento de Astronomia Universidad de Concepcion)


18.10.2017
"TBA"

Krzysztof Belczyński (Copernicus Astronomical Center, Warsaw)


25.10.2017
"Chemical Evolution of Galaxies from Nuclear Astrophysics to Cosmological Structure Formation"

Benoit Côté ( Konkoly Observatory of the Hungarian Academy of Sciences)

Galactic chemical evolution (GCE) is a multidisciplinary topic that involves nuclear physics, stellar evolution, galaxy evolution, observation, and cosmology. Observations, experiments, and theories need to work together in order to build a comprehensive understanding of how the chemical elements synthesized in astronomical events are spread inside and around galaxies and recycled into new generations of stars. The purpose of GCE is to better understand the origin of the elements in the universe and to use chemical abundances to investigate how galaxies form and evolve in a cosmological context. During this talk, I will introduce the basics of GCE and present our efforts to create permanent connections between different fields of research (including nucleosynthesis and gravitational wave physics). In particular, I will present how we used our tools to investigate the possible production sites of light and heavy elements, to quantify output uncertainties and the impact of different modeling assumptions in galaxy models, and to study how structure formation (galaxy mergers) affects the chemical evolution of galaxies in the early universe.


08.11.2017
"Non-standard cosmological tests of gravity"

Wojciech Hellwing (Center for Theoretical Physics, Polish Academy of Sciences, Warsaw)

GR is a "perfect" theory that in the last century successfully undergo many stringent observational tests. Its unchallenged position in both small (Solar System) scales and strong field limits (i.e. BH and NS) made it a natural candidate for the fundamental building block for standard cosmological model (LCDM). However, GR has not been so far rigorously tested in the very low-densities and at intergalactic scales. Thus the reality doors are still quite open for many prospective alternative theories commonly dubbed Modified Gravity. I shall recapture the general landscape of the currently very vibrant field of modified gravity theories. I will also discuss why is it absolutely crucial to find and provide as many as possible independent cosmological tests of GR and its competitors. Finally, I will present some of quite non-standard cosmological tests of gravity that me and my collaborators have put forward recently. These include hierarchical amplitudes (scaled higher-order central moments of the density field) and halo/galaxy clustering ratios.