XRB/AGN VARIABILITY · Exploring the origins and implications of variability in X-ray binary systems and active galactic nuclei
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2006-02-01 → 2007-01-31
- EU contribution
- €145,308
- Participants
- 1
- Scheme
- EIF
Lines connect the coordinator with its partners.
Results in brief
Final Activity Report Summary - XRB/AGN VARIABILITY (Exploring the origins and implications of variability in X-ray binary systems and active galactic nuclei)
The project was in the area of astrophysics and astronomy, with the aim to study and understand the fluctuations seen in the X-ray emission of black holes in our galaxy. The X-rays are thought to come from close to the black holes, where gravitational energy is released from gas as it falls in towards the black hole. The reason why the X-ray emission varies has long been a mystery, but it could hold vital clues to the structure of the flow of gas on to the black hole, and the nature of the processes that produce the X-ray emission. If we can understand these processes, we can make great progress to understanding the physics of matter in conditions of extreme gravity, and gain clues as to how black hole energise their environments, e.g. through the mysterious 'state transitions' which lead to the formation of powerful jets of material away from the black hole. The key result of this project is that X-ray fluctuations were observed coming directly from the accretion disk, gas formed in to a disk as it spirals in to the black hole. This shows that the fluctuations are formed directly in the flow of gas, perhaps due to turbulence. We also observed that the fluctuations got faster in time as the X-ray emission got slightly brighter. This result can be explained if the disk gets thicker over time, since gas moves faster through the disk when it is thicker. This possibility is highly interesting for interpreting the variability, since a change in flow thickness had never before been considered as an explanation for changes in the timing properties of black holes, so the result has implications for understanding variations in many more black hole systems.
Data: CORDIS, © European Union
Project objective
Recent research has shown a deep connection between the X-ray variability properties of accreting black holes on all mass scales, from stellar mass X-ray binary systems (XRBs) to the similarly but much more slowly varying supermassive black holes in Active Galactic Nuclei (AGN).My research has suggested that the variability is due to variations in the accretion flow, which powers the emission from these objects. With a much deeper understanding of the nature and origin of the variability in XRBs we can shed new light on the nature of accretion and its importance for AGN variability.I will investigate XRB variability at a much deeper level and greatly increase my competence in XRB research by working at one of the world's leading institutes for XRB research, the Anton Pannekoek Astronomical Institute (API) in Amsterdam. I will use novel techniques, the rms-flux relation, flux distribution and bispectrum, to explore the origin of X-ray variability in XRBs and shed light on the nature of XRB states and the differences between neutron star and black hole systems.I will use my results to construct toy models for the variability which will shed light on variations in AGN accretion which occur on much longer time-scales than can be probed by observations, and may play an important role in the evolution of AGN and, through their interaction with their environment, the evolution of the Universe.Through exploring the new XRB/AGN synergy in a world-class XRB research group I will increase EU competitiveness in research in both AGN and XRBs, and reach a level of professional maturity which will enable me to pursue a fruitful research career in both AGN and XRB astrophysics.
Original text from CORDIS.
Participants
- UNIVERSITEIT VAN AMSTERDAM · AMSTERDAMCoordinatorNetherlands
Links
Data: CORDIS, © European Union