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.
Astrophysics News & Events
The CIDMA Young Doctor Award is a prize for a researcher within 5 years after the PhD, who has made important contributions to his or her research field. The 2018 award is granted to Gr@v member Tjarda Boekholt for his recent achievements in the field of dynamical chaos in astronomical systems. During the annual meeting of CIDMA 2018, Tjarda presented his new numerical N-body code and the ability to obtain reversible solutions to highly chaotic systems.
In a recent paper "Head on collisions of Proca Stars", [arXiv:1806.07779], by N. Sanchis-Gual et al., head-on collisions of exotic compact objects known as "Proca stars" were studied via fully non linear numerical simulations, with the goal of extracting the gravitational wave templates that such exotic objects could produce.
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).
Black hole (BH) shadows in dynamical binary BHs have been produced via ray-tracing techniques on top of computationally expensive fully non-linear numerical relativity simulations.
On arXiv:1805.03798 [gr-qc], it is illustrated (as a proof of concept) that the main features of these shadows can be captured by a simple quasi-static evolution of the photon orbits on top of a static double-Schwarzschild family of solutions, which is exact.
A team of Gr@v members (P. Cunha, J. Delgado, C. Herdeiro and J. Oliveira) is visiting the Universidad Nacional Autónoma de México, at its Cuernava Campus, in April-May 2018 hosted by Professor Juan Carlos Degollado. The visit occurs within a Marie Curie RISE action, of which both UNAM and Aveiro Universities are partners.
On May 29th, 1919 a joint Royal Astronomical Society and Royal Society expedition led by Arthur Eddington to Principe observed a total solar eclipse, confirming the deflexion of light predicted by the General Theory of Relativity. Eddington at Sundy: 100 years later (E@S) results from a joint initiative of several institutions, including our group, to celebrate the centenary of these observations.
Brown dwarfs are objects that bridge the realms of stars and planets. With masses below ~0.08 MSun, they cannot sustain hydrogen fusion, never reach the main sequence, and remain cooling forever. Star forming regions and young clusters harbour large populations of these substellar objects, including some with masses comparable to those of giant extrasolar planets.