Neutron-star Radius Constraints from GW170817 and Future Detections

By A. Bauswein, O. Just, Hans-Thomas Janka, Nikolaos Stergioulas. 2017

503 citations recorded by the source corpus.

We introduce a new, powerful method to constrain properties of neutron stars (NSs). We show that the total mass of GW170817 provides a reliable constraint on the stellar radius if the merger did not result in a prompt collapse as suggested by the interpretation of associated electromagnetic emission. The radius of nonrotating NSs with a mass of 1.6 can be constrained to be larger than km, and the radius Rmax of the nonrotating maximum-mass configuration must be larger than km. We point out that detections of future events will further improve these constraints. Moreover, we show that a future event with a signature of a prompt collapse of the merger remnant will establish even stronger constraints on the NS radius from above and the maximum mass Mmax of NSs from above. These constraints are particularly robust because they only require a measurement of the chirp mass and a distinction between prompt and delayed collapse of the merger remnant, which may be inferred from the electromagnetic signal or even from the presence/absence of a ringdown gravitational-wave (GW) signal. This prospect strengthens the case of our novel method of constraining NS properties, which is directly applicable to future GW events with accompanying electromagnetic counterpart observations. We emphasize that this procedure is a new way of constraining NS radii from GW detections independent of existing efforts to infer radius information from the late inspiral phase or post-merger oscillations, and it does not require particularly loud GW events.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/fb3d89992c4df431808234c9196335f40586fa7a

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Citations in the corpus

Stellar structure models in modified theories of gravity: Lessons and challenges (2019, background): “03km for the minimum radius of a non-rotating star [34], which can be further refined by future simulations.”
GW170817: Joint Constraint on the Neutron Star Equation of State from Multimessenger Observations (2017, methodology): “Bauswein et al. (2017) combined this observation with empirical relations between NS radii and the threshold mass for prompt collapse, which was previously found by means of simulations with an approximate treatment of general relativity (GR; Bauswein et al. 2013a), to tentatively rule out EOSs…”
Constraints on the neutron star equation of state from AT2017gfo using radiative transfer simulations (2018, methodology): “…of enormous scientific value: They offer insight into the equation of state (EOS) of NSs (Bauswein, Baumgarte & Janka 2013a; Abbott et al. 2017a; Bauswein et al. 2017; Radice et al. 2018), the formation of heavy elements (Just et al. 2015; Wu et al. 2016; Abbott et al. 2017f; Roberts et al.…”
Long-term GRMHD simulations of neutron star merger accretion discs: implications for electromagnetic counterparts (2018, background): “…production (e.g., Kasen et al. 2017; Côté et al. 2018; Hotokezaka et al. 2018), provided unambiguous association between a neutron star merger and a short gamma-ray burst (Abbott et al. 2017b), and set constraints on the dense-matter equation of state (e.g., Bauswein et al. 2017; Margalit ?”
From hadrons to quarks in neutron stars: a review (2017, methodology): “The event has also been used to place constraints on the radii of the initial neutron stars [161], as well as to suggest a lower bound on the tidal deformability of the stars [162].”
Origin of the heaviest elements: The rapid neutron-capture process (2019, background): “, 2020), the observation of an electromagnetic transient which disfavors a prompt collapse to a black hole (Margalit and Metzger, 2017; Bauswein et al., 2017; Shibata et al., 2017; Coughlin et al., 2019; Margalit and Metzger, 2019), together with nuclear physics constraints (Fattoyev et al.”