CaltechAUTHORS
  A Caltech Library Service

Structure of Neutron Stars in Massive Scalar-Tensor Gravity

Rosca-Mead, Roxana and Moore, Christopher J. and Sperhake, Ulrich and Agathos, Michalis and Gerosa, Davide (2020) Structure of Neutron Stars in Massive Scalar-Tensor Gravity. Symmetry, 12 (9). Art. No. 1384. ISSN 2073-8994. https://resolver.caltech.edu/CaltechAUTHORS:20200828-112547312

[img]
Preview
PDF - Published Version
Creative Commons Attribution.

4Mb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20200828-112547312

Abstract

We compute families of spherically symmetric neutron-star models in two-derivative scalar-tensor theories of gravity with a massive scalar field. The numerical approach we present allows us to compute the resulting spacetimes out to infinite radius using a relaxation algorithm on a compactified grid. We discuss the structure of the weakly and strongly scalarized branches of neutron-star models thus obtained and their dependence on the linear and quadratic coupling parameters α₀, β₀ between the scalar and tensor sectors of the theory, as well as the scalar mass μ. For highly negative values of β₀, we encounter configurations resembling a “gravitational atom”, consisting of a highly compact baryon star surrounded by a scalar cloud. A stability analysis based on binding-energy calculations suggests that these configurations are unstable and we expect them to migrate to models with radially decreasing baryon density and scalar field strength.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3390/sym12091384DOIArticle
ORCID:
AuthorORCID
Rosca-Mead, Roxana0000-0001-5666-1033
Moore, Christopher J.0000-0002-2527-0213
Sperhake, Ulrich0000-0002-3134-7088
Agathos, Michalis0000-0002-9072-1121
Gerosa, Davide0000-0002-0933-3579
Additional Information:© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Received: 23 July 2020; Accepted: 14 August 2020; Published: 19 August 2020. We thank Hector Okada da Silva, Fethi Ramazanoğlu, and Christian Ott for discussions. This research was funded by the European Union’s H2020 ERC Consolidator Grant “Matter and strong-field gravity: new frontiers in Einstein’s theory” Grant No. MaGRaTh–646597 and the STFC Consolidator Grant No. ST/P000673/1, the GWverse COST Action Grant No. CA16104, “Black holes, gravitational waves and fundamental physics”. D.G. is supported by Leverhulme Trust Grant No. RPG-2019-350, M.A. is supported by the Kavli Foundation, Computational work was performed on the SDSC Comet and TACC Stampede2 clusters through NSF-XSEDE Grant No. PHY-090003; the Cambridge CSD3 system through STFC capital Grants No. ST/P002307/1 and No. ST/R002452/1, and STFC operations Grant No. ST/R00689X/1; the University of Birmingham BlueBEAR cluster; the Athena cluster at HPC Midlands+ funded by EPSRC Grant No. EP/P020232/1; and the Maryland Advanced Research Computing Center (MARCC). Author Contributions: Conceptualization, R.R.-M., C.J.M., U.S., M.A. and D.G.; methodology, R.R.-M. and U.S.; software, R.R.-M. and U.S.; validation, R.R.-M. and U.S.; formal analysis and investigation, R.R.-M., C.J.M., U.S., M.A. and D.G.; writing–original draft preparation, R.R.-M. and U.S.; writing–review and editing, R.R.-M., C.J.M., U.S., M.A. and D.G.; project administration, C.J.M., U.S. All authors have read and agreed to the published version of the manuscript. The authors declare no conflict of interest.
Group:TAPIR
Funders:
Funding AgencyGrant Number
European Research Council (ERC)MaGRaTh-646597
Science and Technology Facilities Council (STFC)ST/P000673/1
European Cooperation in Science and Technology (COST)CA16104
Leverhulme TrustRPG-2019-350
Kavli FoundationUNSPECIFIED
NSFPHY-090003
Science and Technology Facilities Council (STFC)ST/P002307/1
Science and Technology Facilities Council (STFC)ST/R002452/1
Science and Technology Facilities Council (STFC)ST/R00689X/1
University of BirminghamUNSPECIFIED
Engineering and Physical Sciences Research Council (EPSRC)EP/P020232/1
Maryland Advanced Research Computing CenterUNSPECIFIED
Subject Keywords:modified gravity; scalar-tensor theory; compact objects; relativistic astrophysics
Issue or Number:9
Record Number:CaltechAUTHORS:20200828-112547312
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200828-112547312
Official Citation:Structure of Neutron Stars in Massive Scalar-Tensor Gravity. Symmetry 2020, 12, 1384; doi: 10.3390/sym12091384
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105140
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:28 Aug 2020 21:23
Last Modified:28 Aug 2020 21:23

Repository Staff Only: item control page