Résumé / Abstract Journal-club_Doctorants

Séminaire Doctoral / Seminar PhD

« Cosmic ray feedback: the missing player in the tension between observed and simulated galaxies »

Curro Rodriguez Montero
Institut d'Astrophysique de Paris (Paris, France)

Numerical simulations of galaxy formation have come a long way since the first N-body/hydrodynamical implementations. Much of their progress and success has been fuelled by a combination of better physically motivated sub-grid prescriptions, higher computational power and improved numerical methods. Amongst the main insights gleaned from simulations, it is now well established that without substantial feedback from stars and active galactic nuclei (AGN) galaxies end up much too massive for their host dark matter halos, leading to stark disagreement with observations. Nevertheless, the quest for a comprehensive modelling of feedback mechanisms is still ongoing.

In recent years, it has become more apparent that cosmic rays (CRs) very likely are a major player in shaping galaxy evolution. In this talk, I will introduce you to the complex nature of CR feedback in a suite of high-resolution cosmological simulations of a Milky Way-like galaxy, using state-of-the-art physically motivated stellar feedback models, which do not rely on unrealistically “boosted” calibrations to match specific observational data sets. We use these simulations to disentangle the physics of CR feedback, separately studying CR diffusion and streaming, and compare them to a sub-grid model designed to account for an increase of SNe momentum deposited in the ISM by CRs. We find that our simulations with CRs significantly reduce the stellar mass and alter the gravitational potential of the galaxy, both by suppressing star formation (particularly at high redshift) and by fuelling important mass-loaded, multiphase winds. Overall, these results support the idea that CRs are a fundamental component of galaxy formation and evolution, which play a key role in bringing galaxy properties closer in line with observed scaling relations.
vendredi 20 mai 2022 - 16:00
Salle des séminaires Évry Schatzman, Institut d'Astrophysique
Page web du séminaire / Seminar's webpage