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Numerical simulations of stellar collapse in scalar-tensor theories of gravity

Published version
Peer-reviewed

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Authors

Gerosa, D 
Ott, CD 

Abstract

We present numerical-relativity simulations of spherically symmetric core collapse and compact-object formation in scalar-tensor theories of gravity. The additional scalar degree of freedom introduces a propagating monopole gravitational-wave mode. Detection of monopole scalar waves with current and future gravitational-wave experiments may constitute smoking gun evidence for strong-field modifications of General Relativity. We collapse both polytropic and more realistic pre-supernova profiles using a high-resolution shock-capturing scheme and an approximate prescription for the nuclear equation of state. The most promising sources of scalar radiation are protoneutron stars collapsing to black holes. In case of a Galactic core collapse event forming a black hole, Advanced LIGO may be able to place independent constraints on the parameters of the theory at a level comparable to current Solar-System and binary-pulsar measurements. In the region of the parameter space admitting spontaneously scalarised stars, transition to configurations with prominent scalar hair before black-hole formation further enhances the emitted signal. Although a more realistic treatment of the microphysics is necessary to fully investigate the occurrence of spontaneous scalarisation of neutron star remnants, we speculate that formation of such objects could constrain the parameters of the theory beyond the current bounds obtained with Solar-System and binary-pulsar experiments.

Description

This is the final version of the article. It first appeared from the Institute of Physics via http://dx.doi.org/10.1088/0264-9381/33/13/135002

Keywords

modified theories of gravity, gravitational waves, supernovae

Journal Title

Classical and Quantum Gravity

Conference Name

Journal ISSN

0264-9381
1361-6382

Volume Title

33

Publisher

IOP Publishing
Sponsorship
Science and Technology Facilities Council (ST/H008586/1)
Science and Technology Facilities Council (ST/J005673/1)
Science and Technology Facilities Council (ST/K00333X/1)
Science and Technology Facilities Council (ST/L000636/1)
Science and Technology Facilities Council (ST/M00418X/1)
Science and Technology Facilities Council (ST/M007065/1)
European Research Council (646597)
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (690904)
D.G. is supported by the UK STFC and the Isaac Newton Studentship of the University of Cambridge. U.S. is supported by the H2020 ERC Consolidator Grant “Matter and strong-field gravity: New frontiers in Einstein’s theory” grant agreement No. MaGRaTh–646597, the H2020-MSCA-RISE-2015 Grant No. StronGrHEP-690904, the STFC Consolidator Grant No. ST/L000636/1, the SDSC Comet and TACC Stampede clusters through NSF-XSEDE Award Nos. TG-PHY090003 and TG-PHY100033, the Cambridge High Performance Computing Service Supercomputer Darwin using Strategic Research Infrastructure Funding from the HEFCE and the STFC, and DiRAC’s Cosmos Shared Memory system through BIS Grant No. ST/J005673/1 and STFC Grant Nos. ST/H008586/1, ST/K00333X/1. C.D.O. is partially supported by NSF under award Nos. CAREER PHY-1151197, and PHY-1404569, and by the International Research Unit of Advanced Future Studies, Kyoto University.