In this talk we will discuss the quasinormal modes of neutron stars in modified theories of gravity, in particular, in R^2 gravity. In this model, in addition to the space-time and fluid degrees of freedom that are present in General Relativity, we naturally find a (massive) scalar field.
Spontaneous scalarization is an interesting phenomenon that black holes with a sufficiently large mass or charge spontaneously transit to a solution with
The existence of light, fundamental bosonic fields is an attractive possibility that can be tested via black hole observations.
We study the effect of a tidal field -- caused by a companion star or black hole -- on the evolution of superradiant scalar-field states around spinning black holes.
Nelson Eiró visited Gr@v just before successfully defending his M.Sc. thesis on "Strong lensing of light and shadow of a Black Hole surrounded by a heavy accretion disk", at IST-Lisbon, supervised by C. Herdeiro and P. Cunha. This visit coincided with the beginning of a long term visit by Aichen and Ruyong Li, both graduates from Beijing University of Technology.
Nico Sanchis-Gual and Nuno Santos visited Gr@v. Nico gave a seminar on "Non-linear dynamics of spinning bosonic stars: formation and stability". Nuno, an IST graduate, will join Gr@v as a PhD student in 2020, having been the top ranked candidate in the 2019 Individual FCT grant call in the Physics panel.
In the framework of the COST action MW-Gaia, related with the Gaia (ESA) mission, for which Gr@v member Sonia Anton serves as MC member, a 3-days workshop on "Astrometry and gravitation - A dynamical view of the sky" is being organised on 4-6 December 2019, at the Observatoire de la Côte d’Azur, Mont Gros site, Nice, France. More info here.
I present a review on combined numerical and analytical efforts to construct "geon"-type solutions of the Einstein equations. Geons are time periodic - hence non-radiating - and spatially localized objects.
Spherical boson and Proca stars have been extensively studied in the non-linear regime, but no numerical simulations of rotating bosonic stars have been performed.
The XII Black Holes Workshop, an annual series of meetings organised by the Portuguese strong gravity community since 2008, will take place in Guimarães, on December 19-20, 2019. More information here.
Our group coordinated the "Numerical Relativity and High Energy Physics" IRSES network (2012-2015). Here is a list of the global network meetings organized:
