Galaxies are complex and fascinating objects -- found in various shapes and sizes -- which trace the underlying matter distribution of the Universe. Understanding how they acquire the properties they have today, i.e. deciphering how they form and evolve throughout cosmic history, is a fundamental question of modern astrophysics. 

 

My research focuses on the formation, evolution, and dark matter content of galaxies like our own Milky Way, with an emphasis on the effects of slow, internal, so-called 'secular' processes, which dominate their evolution in the last ~9 billion years. If you're interested in doing a Masters project or a PhD on these topics, don't hesitate to get in touch!  

 

GDR2_fluxRGB_cartesian_4000x2000_edited.jpg

Credit: ESA/Gaia/DPAC

The inner regions of galaxies are the first to assemble, and hold within them a fossil record of their early growth. These are also complex and dynamic regions, where multiple components -- such as the disc, bulge and halo -- overlap. In order to uncover the formation history of our Galaxy, we need to interpret the chemo-dynamical properties of its inner stellar populations, using sophisticated models, such as high-resolution hydrodynamical cosmological simulations.

See e.g.:

Fragkoudi et al. (2020) arXiv:1911.06826

Fragkoudi et al. (2018) arXiv:1802.00453

Fragkoudi et al. (2017c) arXiv:1710.06864

The formation of the Milky Way

After redshift z~1-2, Milky Way-like galaxies are thought to settle into dynamically mature discs, in which internal secular processes dominate their subsequent evolution. To study this late time evolution and to interpret observations of spiral galaxies, I use high resolution simulations -- both tailored and cosmological -- together with orbital structure theory. Such observations include both the detailed phase-space substructures and chemical abundances obtained for the Milky Way from the Gaia satellite and ground-based spectroscopic surveys, as well as for integrated stellar populations of nearby galaxies from IFUs such as MUSE on the VLT.

 

See e.g.:

Fragkoudi et al. (2020) arXiv:1911.06826

Neumann, Fragkoudi et al. (2020) arXiv:2003.08946

Fragkoudi et al. (2019) arXiv:1901.07568

Fragkoudi et al. (2017b) arXiv:1704.00734

Fragkoudi et al. (2016) arXiv:1606.04540

Hubble2005-01-barred-spiral-galaxy-NGC1300.jpeg

Credit: HST/NASA/ESA

The evolution of barred spiral galaxies

Credit: V. Springel

Disentangling the luminous (baryonic) matter from the dark matter in the central regions of galaxies is non-trivial, due to uncertainties in the mass-to-light ratio of the stellar component. To infer how much dark matter is present, we can use dynamical modelling techniques, which account for the complex non-circular motions of stars and gas. This allows us to infer the amount of dark matter in the central regions of galaxies, thus providing a benchmark for cosmological simulations of galaxy formation and evolution, and shedding light on the nature of dark matter itself.

See e.g.:

Fragkoudi et al. (2021) arXiv:2011.13942

Fragkoudi et al. (2017a) arXiv:1611.09386

The dark matter content of spiral galaxies