PhD in Physics

This project aims to recalibrate early universe measurements and deliver precise and accurate supermassive black hole (SMBH) masses using the new GRAVITY+ measurements. Recent observations suggest that quasars in the early universe have SMBHs that are too massive to form in the short time since the big bang, shaking the foundations of cosmology and our understanding of black hole growth. The main problem is that we cannot be sure that the methods employed to estimate those SMBH masses are reliable in the conditions of the early universe. GRAVITY+ will deliver transformational capabilities to measure spatially resolved, dynamical supermassive black hole masses up to redshift 4.5 and possibly beyond. Our first data from such a high redshift quasar indicate that current mass estimates may indeed be out by a factor of 10. Using these new GRAVITY+ measurements, we will be able to recalibrate early universe measurements and deliver precise and accurate SMBH masses. As part of this project, you'll work on GRAVITY+ data of quasars between redshift 1 < z < 4.5, perform dynamical modelling to determine the SMBH masses, and compare those measurements to estimates from more generic methods used in the early universe. With this comparison, you'll be able to characterise how high-luminosity, fast growing objects are offset from local sources and how early universe mass estimates need to be corrected. You'll work in a team funded through an ERC Advanced Grant-selected project, and you'll be embedded in an international collaboration with institutions from across Europe, Australia and China. This will provide ample opportunities to perform research visits abroad and contribute to the wider GRAVITY+ programme.