Combining Electromagnetic and Gravitational-Wave Constraints on Neutron-Star Masses and Radii

Mohammad Al-Mamun; Andrew W Steiner; Joonas Nättilä; Jacob Lange; Richard O'Shaughnessy; Ingo Tews; Stefano Gandolfi; Craig Heinke; Sophia Han

doi:10.1103/PhysRevLett.126.061101

Combining Electromagnetic and Gravitational-Wave Constraints on Neutron-Star Masses and Radii

Phys Rev Lett. 2021 Feb 12;126(6):061101. doi: 10.1103/PhysRevLett.126.061101.

Authors

Mohammad Al-Mamun¹, Andrew W Steiner^{1

2}, Joonas Nättilä^{3

4}, Jacob Lange⁵, Richard O'Shaughnessy⁵, Ingo Tews⁶, Stefano Gandolfi⁶, Craig Heinke⁷, Sophia Han^{8

9}

Affiliations

¹ Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA.
² Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
³ Physics Department and Columbia Astrophysics Laboratory, Columbia University, 538 West 120th Street, New York, New York 10027, USA.
⁴ Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, USA.
⁵ Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, New York 14623, USA.
⁶ Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
⁷ Department of Physics, CCIS 4-183, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.
⁸ Department of Physics, University of California, Berkeley, California 94720, USA.
⁹ Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA.

PMID: 33635682
DOI: 10.1103/PhysRevLett.126.061101

Abstract

We perform a joint Bayesian inference of neutron-star mass and radius constraints based on GW170817, observations of quiescent low-mass x-ray binaries (QLMXBs), photospheric radius expansion x-ray bursting sources, and x-ray timing observations of J0030+0451. With this dataset, the form of the prior distribution still has an impact on the posterior mass-radius curves and equation of state (EOS), but this impact is smaller than recently obtained when considering QLMXBs alone. We analyze the consistency of the electromagnetic data by including an "intrinsic scattering" contribution to the uncertainties, and find only a slight broadening of the posteriors. This suggests that the gravitational-wave and electromagnetic observations of neutron-star structure are providing a consistent picture of the neutron-star mass-radius curve and the EOS.