I am a staff astronomer and group leader at the Max Planck Institute for Astronomy in Heidelberg, Germany. My group focuses on the first billion years of the Universe (redshifts z > 5.5), when the earliest sources of light reionized the intergalactic medium. We discover and characterize the highest-redshift quasars and their cosmic environments using facilities spanning the full electromagnetic spectrum — from JWST and Euclid in the optical and infrared, to NOEMA and ALMA at millimeter wavelengths, Chandra and XMM-Newton in X-rays, and the VLA and MeerKAT in radio.

Our work addresses fundamental questions: How did reionization proceed in time and space? How did the first supermassive black holes and galaxies form and grow? Did they arise in the densest regions of the early Universe? Where are the giant radio jets at high redshift, and how do they impact early galaxy evolution?

I am co-lead of the Primeval Universe Science Working Group within the Euclid collaboration and a member of the Scientific Advisory Committee for the Large Binocular Telescope.