Talk detail

Participant	Altaha Motahar, Zahra
Institution	Oldenburg University - Carl von Ossietzky University of Oldenburg - Oldenburg - Oldenburg - Germany

Session	AC1	Accepted		Order	Time
Talk	Poster abstract	Title	Axial Quasi Normal Modes of Scalarized Neutron Stars with Realistic Equations of State
Coauthors
Abstract	Neutron stars are some of the most complicated and mysterious objects in the universe. Their high compactness and density make these compact objects an interesting astronomical laboratory for studying gravity and testing General Relativity (GR) and alternative theories of gravity in the strong regime. On the other hand, neutron stars consist of extremely dense matter that cannot be produced in ground based laboratories, resulting in our current poor understanding of the physics of matter at supranuclear densities. Recent gravitational wave (GW) detections, and particularly GWs from the binary neutron stars merger GW170817, opened a new window for the study of neutron stars. GW detection provides provide us a new tool for testing GR in the strong gravity regime as well as constraining the equation of state (EOS). Finding universal relations for neutron stars, i.e., relations among physical quantities that are to a large extent independent of the EOS, let us testing GR as well as inferring more information from the observational data. For instance, if the frequency or the damping time is detected by GWs, we may use the quasi-normal modes (QNMs) of the oscillation to find the mass and moment of inertia of compact stars. In this study, we compute the axial QNMs of static neutron stars in scalar-tensor theory (STT). In particular, beside the polytropic EOS, we employ various realistic EOSs including nuclear, hyperonic, hybrid and quark matter. We investigate the fundamental curvature mode and compare the results to those of GR. We find that the frequency of the modes is reduced in STT comparing to GR. In addition, we confirm and extend the universal relations of QNMs known in GR to this wide range of realistic EOSs for scalarized neutron star models. Particularly, we could confirm the universality of scaled frequency or damping time in terms of the scaled moment of inertia for both STT and GR.
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