Theoretical Cosmology meetings
To actively encourage the field of theoretical cosmology and to set an informal stage for the exchange of ideas, the Dutch theoretical cosmology community organizes Friday afternoon meetings approximately 6 times a year — usually on the first Friday of the month. The meetings typically start in the afternoon with a main speaker, followed by a short break to continue with another seminar or journal club discussion on some topic of current interest. We end the afternoon with drinks. The supporting institutes in Leiden, Amsterdam, Groningen, Utrecht where recently joined by the strings and cosmology group in Leuven and take turns in hosting the event.
- This event has passed.
Leiden Winter 2021
05/03/2021 @ 13:15 - 16:15
Leiden, March 5th.
This meeting will take place via remote connection. Here the information for connecting:
Time: March 5, 2021 01:15 PM Amsterdam Time
Join Zoom Meeting
Zoom Link
Meeting ID: 669 5673 2776
Password: w0T+$yeT
13:15 – 14:00: Talk by Kyrylo Bondarenko (CERN)
Title: Cosmological-scale magnetic fields from galactic outflows
Abstract:
We study the effects of galaxy formation physics on the magnetization of the intergalactic medium (IGM) using the IllustrisTNG simulations. We demonstrate that large-scale regions affected by the outflows from galaxies and clusters contain magnetic fields that are several orders of magnitude stronger than in unaffected regions with the same electron density. Moreover, like magnetic fields amplified inside galaxies, these magnetic fields do not depend on the primordial seed, i.e. the adopted initial conditions for magnetic field strength. We study the volume filling fraction of these strong field regions and their occurrence in random lines of sight. We discuss the effects of these strong magnetic fields on Faraday Rotation Measure, ultra-high energy cosmic rays, and put bounds on the photon-axion conversion from spectral distortion of the CMB.
14:00 – 14:45 Talk by Ema Dimastrogiovanni (University of Groningen)
Title: Gravitational waves from inflation

Abstract:
Primordial gravitational waves have the potential to shed new light on the very early universe. In this talk I will discuss gravitational wave production in a variety of models beyond the simplest, single-field, scenarios and highlight some of their implications for testing inflation at interferometer scales.
15:00 – 15:45: Talk by Matteo Martinelli (IFT Madrid)
Title: Testing the assumptions of standard cosmological model: the case of the Distance Duality Relation
Abstract:
Despite the availability of several cosmological models alternative to the standard LCDM, and the presence of observational tensions in the context of this model, still no alternative is preferred over standard cosmology. This might indicate that in order to solve the current observational issues, one might need to relax some of the fundamental assumptions that are at the foundation of the LCDM model. A direct consequence of some of these assumptions is the Distance Duality Relation (DDR), relating the different cosmological distances with each other, which might breakdown in extended theories, e.g. when photons are coupled to beyond standard model particles. In this talk I will discuss how upcoming cosmological surveys will be able to improve current constraints on the DDR, showing both the impact of observational improvements and how new observational windows (standard sirens and strong lensing) will provide new opportunities and new challenges.
15:45 – 16:15: social virtual borrel