Illuminating the Cosmic Web
Galaxies are not isolated objects in space, but are distributed in a great underlying cosmic web of gas filaments spreading throughout the universe. This inter-galactic cosmic web provides the fundamental reservoir for fuelling continued galaxy growth by accretion and condensation onto galactic seeds along gaseous filaments. Utilizing extremely sensitive radio observations, it is possible to trace the neutral gas fraction of the inter-galactic cosmic web and to study the interplay between galaxies and their gaseous environment.
The GOALS Project
Interactions and mergers are important drivers of galaxy evolution, transform spiral galaxies into massive ellipticals, and fuel both powerful starbursts and massive nuclear black holes. In particular one galaxy population, namely Luminous Infrared Galaxies (LIRGs), are believed to be responsible for most of the star formation that happened in the history of the universe, and hence represent a critical phase in the evolution of galaxies where most of the galaxies mass is building up. The GOALS (Great Observatory All-sky LIRG Survey) project combines high-resolution imaging and spectroscopic data in the optical and infrared light (HST, Spitzer, Herschel) for a complete sample of 202 nearby LIRGs, providing a detailed picture of the processes responsible for enhanced infrared emission in the local universe.
NUGA and Gas Dynamics
The main goal of the NUGA (NUclei of GAlaxies) project is to understand the feeding and evolution of a galaxy’s central region and Super-Massive Black Hole (SMBH). Therefore a sample of nearby Active Galactic Nuclei (AGN) is studied using radio interferometric observations (IRAM PdBI, NRAO VLA) and modeling tools to derive gas inflow rates and feeding efficiencies. For more information on NUGA and its latest results feel free to visit the NUGA project homepage.
Click here for the HST image gallery.
The high-resolution poster can be downloaded here (~60MB): poster_HST.pdf
NGC 5257 (Overview of the HI-NUGA survey Haan et al. 2008, 2008AJ....135..232H)
NGC 5257 (Example from the HST GOALS survey, Haan et al. 2011, 
NGC 6951 (Example from the NUGA project, Haan et al. 2009,