4 documents found, page 1 of 1
The reference site collaborative network of the european innovation partnership...
Bousquet, J.; Illario, M.; Farrell, J.; Batey, N.; Carriazo, A. M.; Malva, J.; Hajjam, J.; Colgan, E.; Guldemond, N.; Perala-Heape, M.; Onorato, G. L.Seventy four Reference Sites of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA) have been recognised by the European Commission in 2016 for their commitment to excellence in investing and scaling up innovative solutions for active and healthy ageing. The Reference Site Collaborative Network (RSCN) brings together the EIP on AHA Reference Sites awarded by the European Commission, an...
Light-Ring Stability for Ultracompact Objects
Cunha, P. V. P.; Berti, E.; Herdeiro, C. A. R.We prove the following theorem: axisymmetric, stationary solutions of the Einstein field equations formed from classical gravitational collapse of matter obeying the null energy condition, that are everywhere smooth and ultracompact (i.e., they have a light ring) must have at least two light rings, and one of them is stable. It has been argued that stable light rings generally lead to nonlinear spacetime instab...
Synchronous frequencies of extremal Kerr black holes: Resonances, scattering, a...
Richartz, M.; Herdeiro, C. A. R.; Berti, E.The characteristic damping times of the natural oscillations of a Kerr black hole become arbitrarily large as the extremal limit is approached. This behavior is associated with the so-called zero damped modes (ZDMs), and suggests that extremal black holes are characterized by quasinormal modes whose frequencies are purely real. Since these frequencies correspond to oscillations whose angular phase velocity matc...
Preface by the Editors from Selected Papers of III Amazonian Symposium on Physi...
Herdeiro, C. A. R.; Berti, E.; Cardoso, V.; Crispino, L. C. B.; Gualtieri, L.; Sperhake, U.