Theoretical cosmology meeting

11Jan2019 12:00 - 17:00


Speakers: Filippo Vernizzi (Saclay), Amina Helmi (Groningen University), Sebastian Garcia-Saenz (IAP). Location: Groningen.


The venue is located downtown Groningen, at the Harmonie Building, room 1315.0036, Oude Kijk in Het Jatstraat 26, Groningen >>Googlemaps.  

12:00 – 13:00 Filippo Vernizzi (Saclay) - Dark Energy after GW170817

13:00 – 14:00 Lunch 

14:00 – 15:00 Amina Helmi (Groningen University) - New views on the Galaxy and its satellites from the Gaia space mission 

15:00 – 15:30 Coffee Break

15:30 – 16:30 Sebastian Garcia-Saenz (IAP) - Sidetracked Inflation


Filippo Vernizzi (Saclay) 

Dark Energy after GW170817

I will discuss some of the consequences of gravitational wave observations on (single field) dark energy and modified gravity. In particular, I will show that in some models gravitational waves can decay into dark energy and that the absence of this effect provides constraints on the space of parameters. 

Amina Helmi (Groningen University) 

New views on the Galaxy and its satellites from the Gaia space mission. 

The recent 2nd data release of the Gaia mission took place in April 2018. It is currently revolutionizing our understanding of the Milky Way and its constituents. In this talk, I will highlight a few of the first results stemming from the analysis of this truly spectacular dataset. In particular, I will focus on what we have learned about the dynamics, mass distribution and assembly of the Milky Way and its satellites thus far.

Sebastian Garcia-Saenz (IAP) 

Sidetracked Inflation 

Heavy scalar fields can undergo an instability during inflation as a result of their kinetic coupling with the inflaton. This effect is known as the geometrical destabilization of inflation, as it is caused by the curvature of the internal manifold parametrized by the fields. The instability can drive the system away from its original path in field space into a new inflationary attractor, a scenario that we call “sidetracked inflation”. This talk will aim at describing the physics of this second phase and its observable consequences. I will show that the behavior of cosmological fluctuations can be understood by means of a single-field effective theory in which perturbations propagate with either a modified dispersion relation, a reduced speed of sound, or a speed of sound that is imaginary. The latter case is especially interesting as it leads to novel observational signatures, and in particular to unusual shapes in the non-Gaussianities.


The venue is located downtown Groningen, at the Harmonie Building, room 1315.0036.

Oude Kijk in Het Jatstraat 26, Groningen, The Netherlands >>Googlemaps.

Local organiser

Diederik Roest (RUG)


These meetings occur (roughly) every month and are hosted by universities across the Netherlands, gathering the local cosmology community. Some of these talks might be of interest also for string and the Amsterdam GRAPPA groups, so we encourage you to subscribe to the THC mailing list:

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source: THC@NL

Published by  D-ITP