Constraining the Maximum Mass of Neutron Stars from Multi-messenger Observations of GW170817

By B. Margalit, B. Metzger. 2017

715 citations recorded by the source corpus.

We combine electromagnetic (EM) and gravitational-wave (GW) information on the binary neutron star (NS) merger GW170817 in order to constrain the radii and maximum mass of NSs. GW170817 was followed by a range of EM counterparts, including a weak gamma-ray burst (GRB), kilonova (KN) emission from the radioactive decay of the merger ejecta, and X-ray/radio emission consistent with being the synchrotron afterglow of a more powerful off-axis jet. The type of compact remnant produced in the immediate merger aftermath, and its predicted EM signal, depend sensitively on the high-density NS equation of state (EOS). For a soft EOS that supports a low , the merger undergoes a prompt collapse accompanied by a small quantity of shock-heated or disk-wind ejecta, inconsistent with the large quantity of lanthanide-free ejecta inferred from the KN. On the other hand, if is sufficiently large, then the merger product is a rapidly rotating supramassive NS (SMNS), which must spin down before collapsing into a black hole. A fraction of the enormous rotational energy necessarily released by the SMNS during this process is transferred to the ejecta, either into the GRB jet (energy ) or the KN ejecta (energy ), also inconsistent with observations. By combining the total binary mass of GW170817 inferred from the GW signal with conservative upper limits on and from EM observations, we constrain the likelihood probability of a wide range of previously allowed EOSs. These two constraints delineate an allowed region of the parameter space, which, once marginalized over NS radius, places an upper limit of (90%), which is tighter or arguably less model-dependent than other current constraints.

Subfields: Astronomy and Astrophysics, Atmospheric Science

View Paper: https://www.semanticscholar.org/paper/e96829ec1d20444c3c432dea9b9c0a9bc5e374fb

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In Astronomy and Astrophysics

1. B. Metzger
2. Michela Mapelli
3. E. Berger
4. E. Quataert
5. David Radice
6. Ilya Mandel
7. D. Holz
8. N. Giacobbo

In Atmospheric Science

1. B. Metzger
2. E. Quataert
3. E. Berger
4. Bernard F. Schutz
5. P. Lasky
6. A. Bauswein
7. W. Fong
8. D. Holz

Citations in the corpus

• The Binary Neutron Star Event LIGO/Virgo GW170817 160 Days after Merger: Synchrotron Emission across the Electromagnetic Spectrum (2018, background): “As a comparison, in classical SGRBs, long-lived magnetars with rotational energy in the range & 1051 − 1054 erg are also ruled out (Fong et al. 2016; Margalit & Metzger 2017).”
• Constraints on the neutron star equation of state from AT2017gfo using radiative transfer simulations (2018, background): “GR simulations show that the latter is a fairly generic outcome of the merger process if the merger remnant first goes through a hypermassive NS phase (e.g. Shibata & Taniguchi 2006), and thus our observations disfavour a prompt collapse (see also Bauswein et al. 2017; Margalit & Metzger 2017).”
• A Magnetar Origin for the Kilonova Ejecta in GW170817 (2018, background): “…in order to collapse in this case would have been observationally conspicuous and thus is disfavored (Granot et al. 2017; Ma et al. 2017; Margalit & Metzger 2017; Margutti et al. 2017; Pooley et al. 2017). neutrino heating of the surrounding accretion disk (e.g., Metzger & Fernández…”
• Combined Constraints on the Equation of State of Dense Neutron-rich Matter from Terrestrial Nuclear Experiments and Observations of Neutron Stars (2018, methodology): “For instance, Margalit & Metzger (2017) used electromagnetic constraints on the remnant imposed by the kilonova observations after the merger and the gravitational wave information predicted a maximum mass of Mmax ≤ 2.17M⊙ with 90% confidence.”
• Tidal Deformability from GW170817 as a Direct Probe of the Neutron Star Radius (2018, methodology): “For example, Margalit & Metzger (2017) used the combined gravitational wave and electromagnetic signals to set an upper limit on the maximum neutron star mass, which is a sensitive constraint on the equation of state at high densities (Özel & Psaltis 2009).”
• GW170817: Joint Constraint on the Neutron Star Equation of State from Multimessenger Observations (2017, methodology): “Margalit & Metzger (2017) argued that the merger remnant might not have formed a long-lived remnant because of the relatively low energy of the ejecta inferred from optical and infrared data.”
• Neutron-star Radius Constraints from GW170817 and Future Detections (2017, methodology): “We note that evidence for a long-lived merger remnant (e.g. Lippuner et al. 2017; Margalit & Metzger 2017) further strengthens our arguments.”