I learned physics at the Autonomous University of Barcelona, and astronomy on my own and through some amateur associations in Catalonia. I did my PhD in astrophysics at Princeton University, graduating in 1991 with a thesis on gravitational lensing by clusters and large-scale structure. I was a postdoc at the Institute of Astronomy in Cambridge, and a Long-Term Member at the Institute for Advanced Study. I joined the University of Pennsylvania as a professor of astrophysics in 1996, and then moved to The Ohio State University in 2000. I have been back to Catalonia with an ICREA position since 2005, and I am at present doing research on astrophysics and cosmology at the Institut de Ciències del Cosmos at the University of Barcelona.

Research interests

I enjoy searching for physical explanations for what we observe in the Universe. My interests range over the formation of galaxies and their large-scale distribution in space, the composition and evolution of the universe as a whole, observations of the intergalactic medium that help us understand the distribution of matter in space, the physics of active galactic nuclei and the formation of massive black holes, and gravitational lensing as a probe to the space distribution and the nature of dark matter. Over the last few years I have focused on the study of the large-scale distribution of intergalactic gas with the use of quasar spectra from the Baryon Oscillation Spectroscopic Survey of the SDSS-III Collaboration, where absorption in the Lyman alpha line of hydrogen gas is observed. This is revealing crucial clues on both the initial conditions of the Universe and the formation of galaxies. Among other things I have worked on Damped Lyman Alpha Systems, which are clouds of hydrogen gas that we observe in these quasar absorption spectra and are in the process of forming galaxies, and also on diffuse Lyman Alpha emission from galaxies and the intergalactic medium.