Marianne Vestergaard received her PhD in astrophysics from the Niels Bohr Institute in 1999 after a lengthy research stay at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, USA. Since then, she has worked at Ohio State University, the University of Arizona, and Tufts University in Medford, Massachusetts, all in the United States. In 2009, Marianne returned to the Niels Bohr Institute as a Freja Fellow at the Faculty of Science at the University of Copenhagen. Marianne is now Professor at the Niels Bohr Institute.

Marianne is researching the physics of distant, young galaxies called quasars. They emit strong radiation due to material falling on a super-heavy black hole in the center of the galaxy. Marianne is particularly interested in determining the mass of the black holes and investigating how the powerful energy emission from the central active core of the quasars affects their surroundings. Marianne uses a wealth of telescopes both in space and on Earth, which are sensitive to X-rays, ultraviolet, visual, infrared, sub-millimeter and radio radiation. Most recently, she has used data from the large 'Very Large Telescope' at the European Southern Observatory in Chile, the Atacama Pathfinder Experiment (APEX), the Atacama Large Millimeter Array (ALMA), the Hubble Space Telescope, and the Swift X-ray and UV optical telescope.