Thesis

Perturbative stability of novel rotating compact objects

• Call:

  IDPASC Portugal - PHD Programme 2016

• Academic Year:

  2016 / 2017

• Domains:

  General Relativity | Astrophysics

• Supervisor:

  Vitor Cardoso

• Co-Supervisor:

  Carlos Herdeiro

• Institution:

  Instituto Superior Técnico

• Host Institution:

  Instituto Superior Técnico

• Abstract:

  The detection of the gravitational wave event GW150914, has provided strong evidence for the existence of very compact objects in the Universe. Whereas the observations are well fitted by the paradigmatic black holes of General Relativity, it is important, and timely, to review the evidence that such events pose for the existence of event horizons. In other words, can the same signal be obtained by considering other compact objects_ One of the most interesting types of non-black hole compact object are scalar and vector boson stars, which are known both for spherically symmetric and rotating configurations. Both these objects, moreover, can be generalized to include a rotating horizon in their interior, giving rise to a type of "hairy" black holes. An important step to understand the physical importance of these objects is to consider their perturbative stability. This has been done for the spherically symmetric boson star solutions. For the rotating stars or hairy BHs, however, this is a technically challenging problem, since the coupled matter-gravity perturbations and are not known to separate. The main goal of this thesis will be to address the perturbative stability of the various families of rotating (scalar or vector) boson stars and of their hairy black hole generalizations. Particular attention will be given to the interplay between physical properties of the spacetimes (such as stable light rings and ergo-regions) and the development of instabilities. These results will be important to complement ongoing efforts by the community to perform non-linear numerical evolutions with this objects, that can also test their stability.