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Dr Freeke van de Voort

Dr Freeke van de Voort

Royal Society University Research Fellow & Lecturer
Cardiff Hub for Astrophysics Research and Technology

School of Physics and Astronomy

Users
Available for postgraduate supervision

Overview

In March 2020 I started at Cardiff University as a Royal Society University Research Fellow and lecturer. For those of you who are wondering: my first name, Freeke, rhymes with "Brake a [leg]" and my last name, van de Voort, means "of the Ford". Previously, I worked at MPA as a postdoctoral researcher, at HITS and Yale as a Tschira fellow, and at UC Berkeley and Academia Sinica as a TAC-ASIAA fellow. In 2012 I obtained my PhD from Leiden University.

My research focuses on the study of galaxy formation for which I generally use cosmological, (magneto)hydrodynamical simulations. I am interested in the evolution of galaxies and the circumgalactic and intergalactic medium. More specifically, I study the gas flows between these different regions and how they influence chemical enrichment. My work emphasizes the connection between simulations and observations, because we need both in order to understand how the universe works.

Biography

Since March 2020 I've been a University Research Fellow and lecturer at Cardiff University in the School of Physics and Astronomy. Before this, I did a short postdoc at the Max Planck Institute for Astrophysics in Garching, Germany. I moved to Garching from Heidelberg where I was working as a Tschira fellow at the Heidelberg Institute for Theoretical Studies, a position that was joint with Yale University in New Haven, USA. For my first postdoc I spent 4 years at UC Berkeley in California and at Academia Sinica in Taipei, Taiwan.

I obtained my PhD on The growth of galaxies and their gaseous haloes in 2012 from Leiden University in The Netherlands, where I was working with Joop Schaye. Prior to this, I did my MSc (in astronomy) and BSc (in astronomy and in physics) also at Leiden University.

Publications

2021

2020

2019

2018

2017

2016

2015

2013

2012

2011

2010

Galaxy formation

My research focuses on understanding galaxy formation and evolution. For this purpose, I primarily use cosmological, (magneto)hydrodynamical simulations, but I have worked with observational data as well. I study the interplay between gas accretion and feedback and thus how galaxies grow. Within this field of research, I have worked on a range of topics (see also my publications). Below I describe the two areas to which I am currently devoting most of my time.

Circumgalactic medium

Galaxies are intimately connected to the environments they live in. The gaseous haloes arounds galaxies, the circumgalactic medium, is both the reservoir of gas that provides the fuel for galaxy growth and the repository of enriched gas expelled from galaxies by galactic outflows. Most cosmological, hydrodynamical simulations focus their computational effort on the galaxies themselves and treat the CGM more coarsely, which means small-scale structure cannot be resolved. We have therefore developed a new technique that adds uniform spatial refinement within the halo, increasing the resolution by 2 orders of magnitude for without a prohibitive increase in computational cost (van de Voort et al. 2019). The improved spatial resolution results in smaller dense clumps and more pronounced underdensities. It does not impact the central galaxy or the average density of the CGM. However, it drastically changes the radial profile of the neutral hydrogen column density. Simulating the circumgalactic medium accurately is vital for correctly interpreting at least some of its observational properties. I am currently exploring physical processes such as magnetic field in a new suite of simulations. These topics are still only the tip of the iceberg for what can be studied with these groundbreaking simulations, so stay tuned or feel free to contact me if you would like to get involved.

Chemical evolution

The flow of gas throughout cosmic time is responsible for setting the elemental abundances in present-day stars, together with the elemental yields from various production sites. Stellar abundances observed in the present-day universe (e.g. in the Milky Way and its satellites) can therefore be used to probe the metal production sites as well as the distribution and mixing of these metals throughout the universe at earlier times. Observations have revealed a large spread in rapid neutron capture (r-process) elements at low metallicity as well as striking differences between Milky Way satellites. To help figure out the origin of these elements, we have added 10 r-process production models to high-resolution simulations of Milky Way-like galaxies (van de Voort et al. 2020). Current (sparse and potentially biased) observations of metal-poor stars in the Milky Way seem to prefer rare core-collapse supernovae over neutron star mergers as the dominant source of r-process elements. I am planning to explore the effects of neutron star kicks, which will impact the distribution of these elements. An improved multi-phase model for the ISM may also change how efficiently metal mixing occurs. Please let me know if you have a favourite r-process enrichment model you would like to test in a cosmological context or if you would like to work with the available data.

Supervision

Areas within astronomy available for PhD projects:

  • Galaxy formation
  • Cosmological, magnetohydrodynamical simulations
  • Circumgalactic medium
  • Chemical enrichment including neutron capture elements

Current supervision

Andrew Hannington

Research student

Areas of expertise