Cosmology is the study of the large scale structure of the Universe, as well as its dynamics. Our group has been involved in the study and development of cosmological models, in particular to explain the accelerated phases of the cosmological evolution, dubbed inflationary phases.
For our latest developments/activities in this area, please see the listing below.
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).
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 black hole theorist and cosmologist Stephen Hawking passed away at the age of 76. Stephen Hawking distinguished himself not only as a brilliant scientist, with remarkable contributions such as the discovery of black hole evaporation, but also as an active science communicator with best selling books, most notably A brief history of time.
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.
