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Exotic Compact Objects

exotic Object

Beyond the Standard: Modelling Exotic Compact Objects and Exotic Forms of Matter

While there is good evidence that GW170817, GRB170817A, and AT2017gfo were created by the coalescence and merger of two neutron stars, it cannot yet be ruled out that the observed gravitational waves and electromagnetic signals came from the merger of a neutron star with a neutron star-mimicker. In fact, it is difficult to clearly distinguish neutrons stars from exotic compact objects, e.g. boson stars. Boson stars are stable solitonic solutions to the coupled Einstein-Klein-Gordon equations, which describe a massive scalar field in the presence of gravity. Axion stars are a particular kind of boson stars with a real scalar field and an additional self interactions. We simulate boson stars and axion star binaries and mixed binaries consisting of a neutron star and a neutron star-mimicker. In addition, we investigate how other effects like axion cooling will change the compact binary coalescence.