In this work, the parameter ranges are for 68% credibility interval unless specifically mentioned. With Equation (1), the amount of the post-merger gravitational radiation can be reasonably/qualitatively evaluated as long as 





 (i.e., the EoS) is known. However, various EoS models have been proposed in the literature and it is not possible to be uniquely determined even in the foreseeable future. Fortunately, under the reasonable assumption that all NSs follow the same EoS, their properties can be jointly/reliably constrained with the nuclear data, the GW data, the measured masses, and the estimated radii of some NSs (e.g., Lattimer & Prakash 2016; Abbott et al. 2017a; Tews et al. 2017; Most et al. 2018; Landry & Essick 2019). The masses of NSs in some binary systems have been accurately measured and there is a robust lower limit on MTOV ≥ 2 M⊙ (Cromartie et al. 2020; Kandel & Romani 2020). The radii of NSs, however, usually are just evaluated indirectly and suffer from large systematical uncertainties. Thanks to the successful performance of the Neutron Star Interior Composition Explorer, the situation has changed and very recently the first-ever accurate measurement of mass and radius together for PSR J0030+0451, a nearby isolated quickly rotating NS, has been achieved (Miller et al. 2019; Riley et al. 2019), which favor a stiffer EoS than the data of GW170817. Hence, GW170817, PSR J0030+0451, some nuclear data as well as the lower limit on MTOV can be combined to reliably constrain the EoS as well as the bulk properties of NSs. This can be done either in the EoS parameterizing methods (Raaijmakers et al. 2019; Jiang et al. 2020) or the nonparametric approach (Essick et al. 2020; Landry et al. 2020), and the results are well consistent with each other. Here we directly adopt posterior samples of {MA, MB, ΛA, ΛB} obtained in Jiang et al. (2020) to calculate the 





 for GW170817. Note that the region of 





 represents the prompt black hole formation, which is irrelevant to GW170817 because of the delayed collapse of the remnant (Metzger 2019). So we neglect the posterior samples that give 





 for GW170817. At 90% credible level, for the piecewise polytropic expansion method we have 





, while for the spectral decomposition method we have 





. We also adopt the method described in Kumar & Landry (2019) to evaluate the nonparametric posterior of PSRs+GWs+x-ray/Riley case in Landry et al. (2020) and get 





 for GW1708017. The incorporation of the strong phase transition possibility by Landry et al. (2020) favors lower k2T than ours (note that the 





 region is excluded), but has an overall agreement with the piecewise result and the spectral result (as shown in upper panel of Figure 1). For this reason we combine an equal sample of k2T calculated from these three different parameterization methods to perform all the calculations in this work unless specially specified. Clearly, the inferred 





 is well within the region that predicts the very prominent post-merger GW radiation, which is rather encouraging. The post-merger energy is then estimated to be 





 (90% confidence level) when the fitting error is considered for the combined posterior (see the upper panel of Figure 2). For B1534+12, B2127+11C, J1757-1854, and J0453+1559, we expect that they would emit almost the same amount of energy as GW170817 in the post-merger phase. This is understandable considering the comparable total mass of these systems. For lighter BNS systems like J0514-4002A, the expected post-merger energy is relatively small because of the large 





. While for heavier BNS systems like GW190425, we predict a prompt collapse scenario and thus emit a small amount of energy in the post-merger phase (see the lower panels of Figures 1 and 2). To our knowledge, ours is the first study to combine the intriguing numerical finding of Zappa et al. (2018) with the EoS constrained with the multimessenger information of NSs and then to demonstrate that GW170817 is likely the most efficient post-merger GW emitter among the observed BNS GW events.
Citation: Raaijmakers et al. 2019
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