Sá, PauloLehodey, Brigitte Melo Tomé2011-09-072011-09-072007524 LEH*Mod Cavehttp://hdl.handle.net/10400.1/255Tese dout., Física - Astrofísica, Universidade do Algarve, 2007This thesis is devoted to the study of r-modes in neutron stars. Its aim is to determine the in°uence of di®erential rotation on the evolution of the r-mode insta- bility and on the detectability of gravitational waves from the r-mode. Di®erential rotation, as shown recently, is an unavoidable feature of nonlinear r-modes. We analyse the role played by this di®erential rotation on the evolution of the r-mode instability in newly-born neutron stars. We show that, due to the presence of dif- ferential rotation, the amplitude of the r-mode saturates in a natural way, whereas the angular velocity of the star decreases to values compatible with observational data. We also study the detectability of gravitational waves emitted by newly-born neutron stars, due to the r-mode instability, taking into account di®erential rotation. We show that the detectability of these waves depends crucially on the di®erential rotation associated to the r-mode instability. For small initial di®erential rotation, gravitational waves could be detected by the advanced laser interferometer detectors LIGO and Virgo, if the neutron star is located less than 20 Mpc away from Earth.application/pdfporTesesAstrofísicaEstrelasGrevitação universalRotaçãodoctoral thesis101168535