Accretion disks feed black holes and relativistic jets release spin energy stored in the ergosphere.
Observations of distant quasars and their local dormant counterparts can be used to infer the build up of supermassive black holes subject to assumptions about accretion efficiency and how rotational energy is stored in, and released from, the ergosphere of spinning black holes. Simple-minded calculations suggest that constraints on efficiency may be uncomfortably close to maxima suggested by theories for spinning black holes. This project will couple state-of-the-art datasets with theories to determine the role of black hole spin in the growth of black holes.
For the first time in astronomy, some regions of the sky are becoming so deeply observed at all wavebands from X-ray through to radio that it should be possible to use this information to measure both the active accretion onto black holes, and the energy output in terms of jets powered by spinning black holes.
The first task will be to develop robust ways of measuring jet output using new deep radio observations with the GMRT in India, and the WSRT in Holland.
The second task will be to develop a new and sophisticated `photometric redshift' code that will start with input catalogues covering all wavebands from X-ray to radio, and output probability distributions for redshift and accretion rate, providing a robust way of quantifying the accretion history of black holes.
The third task will be to apply this code to data from the VISTA Deep Extragalactic Observatioins (VIDEO) survey to be carried out on the ESO VISTA telescope in Chile. The student will be expected to help in the collection and processing of VIDEO data, and will lead the analysis relevant to the quantification of the accretion/spin link for black holes.
The fourth task will be to determine whether it is possible to prove that the storage of spin, and feedback via jets, is a key part of the build-up of black holes.
The fifth and final task will be to collect a PhD, and hopefully go on to a glorious career in astrophysics.
If you are at all interested in this project
please have a look at
this poster and
contact either of the supervisors directly via email at the addresses
given below.
Steve Rawlings is Head of Astrophysics at Oxford. He has expertise in observational cosmology.
Tom Mauch is a Postdoctoral Reseacher in observational cosmology, and is expert in designing and undertaking large surveys at radio and optical wavebands.
Hans-Rainer Klöckner is a Postdoctoral Reseacher in Oxford,
and is the SKA Design Study (SKADS) science simulations organiser throughout
Europe.