Active Galactic Nuclei PhD Projects
Research projects on offer in our Active Galactic Nuclei group.
X-ray and infrared probes of black hole growth and obscuration
Accreting supermassive black holes, powering Active Galactic Nuclei (AGN), can produce radiation across the electromagnetic spectrum. However, obscuring dust often blocks the emission at many wavelengths. X-ray emission, particularly high-energy (i.e. hard) X-rays, can penetrate much of this obscuring material and the emergent X-ray spectrum is left with imprints of the structure and composition of the obscuring material. The obscuring dust is also heated by the incident radiation and re-radiates at mid-infrared wavelengths, providing another powerful tracer of the obscuring dust and the presence of a central, growing black hole. Thus, with deep and wide surveys, X-ray and infrared selection can be used to identify large samples of AGN stretching across cosmic time. However, these samples do not perfectly overlap, with each method appearing to identify distinct and unique AGN populations.
The aim of this PhD project will be to quantify the overlap and uniqueness of X-ray and infrared AGN samples, to determine how this depends on the depth of each of the available datasets, and to generate new tools to robustly quantify supermassive black hole growth across cosmic time. To this end, we will employ a broad range of datasets. This will include some of the new deep observations with the James Webb Space Telescope, which are revealing unexpectedly large populations of infrared-bright AGN that are not found in overlapping deep X-ray data from the Chandra telescope. The student will also have the opportunity to join the international SDSS-V collaboration, exploiting our programme of spectroscopic follow-up of hard X-ray selected AGN and quantifying their infrared properties.