Cosmology News & Events
Abstract: In this talk, we present whether the new ekpyrotic scenario
can be embedded into ten-dimensional supergravity. We use that the
scalar potential obtained from flux compactifications of type II
supergravity with sources has a universal scaling with respect to the
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).
The University of Aveiro and Gr@v join the many worldwide tributes to the life and work of Stephen Hawking. As a small contribution, the U. Aveiro asked Gr@v member C. Herdeiro to write an article for its online news that can be found here. A video statement can be found here (both in Portuguese).
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.
One well known problem of the standard cosmological constant model is the tension between the high level of clustering observed in the CMB and the one obtained from large-scale structures. This may be an indication that the way dark energy affects clustering might differ from a simple cosmological constant.
"SKA days PT" took place last 6 and 7 of February, at Covilhã and Lisbon, an initiative to promote the Square Kilometer Array (SKA) - the world's largest radio telescope - among the Portuguese scientific and business communities.
SKA project has the participation of 19 countries, in the case of Portugal it is via the infrastructure ENGAGE SKA, which is a consortium composed by the Instituto de Telecomunicações, the Universities of Aveiro (Gr@v), Porto and Évora, and the Polytechnic Institute of Beja.
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.