In a recent paper "Spontaneous scalarisation of charged black holes: coupling dependence and dynamical features", [arXiv:1902.05079], by Gr@v members A. Pombo and E. Radu, in collaboration with a group at IST-Lisbon (P. Fernandes, C. Herdeiro and N. Sanchis-Gual), fully non-linear evolutions of the process of spontaneous scalarisation of charged black holes.
High Energy Physics News & Events
Gr@v member Valério Ribeiro was part of an international team of researchers studying thermonuclear eruptions in the Andromeda galaxy. The team published, in Nature magazine, the discovery of a super-nova remnant which is bigger than most supernova remnants. They found that the super-nova remnant was the consequence of yearly repeated eruptions over millions of years. Few of these systems are known in the galaxy due to the fact that we suffer from dust obscuration.
João Rosa was interviewed for Porto Canal's "Mentes que brilham" about his work on stimulated axion decay around primordial black holes as a possible origin for fast radio bursts, recently published in Physical Review Letters. He also gave a related interview to the radio programme "Click" on Antena 1.
Watch the presentation movie of the COST Action CA16104 Gravitational waves, black holes and fundamental physics (GWverse), in which Gr@v is involved as part of the core group.
The movie was created at the University of Aveiro (Portugal), written and directed by Carlos Herdeiro, with Design and Graphics by Joana Reis and Ana Sousa and Edited by Pedro Henriques.
The article "Stimulated axion decay in superradiant clouds around astrophysical black holes" (arXiv:1709.06581), co-authored by Gr@v member João Rosa and Tom Kephart (Vanderbilt University, USA), has been accepted for publication in Physical Review Letters and will be highlighted as one of the PRL Editors' Suggestions (a distinction attributed to about one in six Letters).
Greybody factors and quasinormal modes under scalar perturbations in two concrete exactly solvable models
Greybody factors are frequency dependent quantities that measure the deviation from the perfect black body spectrum of Hawking radiation, and they provide us with valuable information about the near horizon structure of black holes. In
addition, when black holes are perturbed the geometry of spacetime undergoes dumbed oscillations.