2014/07/31 by Javier Chagoya, Kazuya Koyama, Gustavo Niz +1 · 2 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Context (archaeology) #Cosmology and Gravitation Theories #Fifth force #General relativity #Gravitation #Neutron star #Polytropic process #Pulsars and Gravitational Waves Research #Scalar (mathematics) #Scalar field #Tensor (intrinsic definition) #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2014/10/055
published as JCAP10(2014)055 · 32 pages, 11 figures, published in JCAP
openalex publication_date 2014/10/22 · arxiv created 2014/11/05 · arxiv updated 2014/11/07 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In the context of a cubic Galileon model in which the Vainshtein mechanism suppresses the scalar field interactions with matter, we study low-density stars with slow rotation and static relativistic stars. We develop an expansion scheme to find approximated solutions inside the Vainshtein radius, and show that deviations from General Relativity (GR), while considering rotation, are also suppressed by the Vainshtein mechanism. In a quadratic coupling model, in which the scalarisation effect can significantly enhance deviations from GR in normal scalar tensor gravity, the Galileon term successfully suppresses the large deviations away from GR. Moreover, using a realistic equation of state, we construct solutions for a relativistic star, and show that deviations from GR are more suppressed for higher density objects. However, we found that the scalar field solution ceases to exist above a critical density, which roughly corresponds to the maximum mass of a neutron star. This indicates that, for a compact object described by a polytropic equation of state, the configuration that would collapse into a black hole cannot support a non-trivial scalar field.