Research

In our current paradigm of cosmological structure formation, gravitational collapse during the Universe’s first billion years transformed a nearly homogeneous matter distribution into a network of filaments astronomers call the “Cosmic Web". Galaxy formation occurs within the densest parts of these filamentary structures and galaxy evolution is expected to be sustained and regulated by gas infall from the Cosmic Web or the Intergalactic Medium (IGM).

Thanks to innovative methods using quasars as "flashlight" to illuminate their surrounding medium on cosmological scales and new instruments, such as the MUSE integral-field-spectrograph on the ESO/Very-Large-Telescope, we can now detect and study the IGM directly in emission. These observations can finally provide vital information on physical properties like the size, morphology, density, clumpiness and temperature of the diffuse gas within the Cosmic Web. However, no real progress can be made if these new observations are not supported by a similar advance in our capability to imagine and understand, to model and interpret. The goal of our research is to provide the necessary theoretical and numerical understanding for the design, implementation and interpretation of innovative observational surveys that will "illuminate" the Cosmic Web.

 In particular, the main goals of our research projects include:

• revealing and studying high-z gas clouds associated with the smallest dark matter haloes that contain cold gas and “dark” proto-galaxies - the building blocks of current galaxy population;

• inferring, by comparison with numerical models, which physical parameters – e.g., the gas surface density, metallicity or molecular hydrogen fraction – control galaxy formation in the Early Universe;

• mapping and studying, in emission, the morphology and kinematics of the Circumgalactic Medium around star forming galaxies in order to reveal how galaxies get their gas;

• studying the three-dimensional morphology and physical properties of the Cosmic Web, e.g. gas density, temperature and clumpiness and how these are affected by local hydrodynamical instabilities and/or galaxy feedback.