Merger remnant and GRB launching regions on the component mass plane. The filled coloured regions correspond to different BNS merger remnants on the (M₁, M₂) plane, assuming different EoSs: APR4 (left-hand panel), SFHo (central panel) and DD2 (right-hand panel). Grey hatches mark masses that are above the maximum non-rotating mass supported by the EoS. The black dashed lines enclose the region where our GRB jet-launching conditions are met, computed as described in Sect. 3.1 (the blue dashed lines, shown for comparison, are computed with the approximate method described in Sect. 3.3). White circles and contours show the best fit and 90% credible contours of masses of known Galactic BNS systems whose coalescence time t_merge is shorter than a Hubble time (t_H, data from Farrow et al. 2019). The orange and green contours show the 50% and 90% credible regions for the component masses in GW170817 (Abbott et al. 2019) and GW190425 (Abbott et al. 2020a), respectively, adopting low-spin priors.