2020MNRAS.499L..82M -
Mon. Not. R. Astron. Soc., 499, L82-L86 (2020/November-3)
A lower bound on the maximum mass if the secondary in GW190814 was once a rapidly spinning neutron star.
MOST E.R., PAPENFORT L.J., WEIH L.R. and REZZOLLA L.
Abstract (from CDS):
The recent detection of GW190814 featured the merger of a binary with a primary having a mass of ∼23 M☉ and a secondary with a mass of ∼2.6 M☉. While the primary was most likely a black hole, the secondary could be interpreted as either the lightest black hole or the most massive neutron star ever observed, but also as the indication of a novel class of exotic compact objects. We here argue that although the secondary in GW190814 is most likely a black hole at merger, it needs not be an ab-initio black hole nor an exotic object. Rather, based on our current understanding of the nuclear-matter equation of state, it can be a rapidly rotating neutron star that collapsed to a rotating black hole at some point before merger. Using universal relations connecting the masses and spins of uniformly rotating neutron stars, we estimate the spin, 0.49–0.05+0.08 ≲χ≲0.68–0.05+0.11, of the secondary - a quantity not constrained so far by the detection - and a novel strict lower bound on the maximum mass, MTOV> 2.08+0.04–0.04 M☉ and an optimal bound of MTOV> 2.15+0.04–0.04 M☉, of non-rotating neutron stars, consistent with recent observations of a very massive pulsar. The new lower bound also remains valid even in the less likely scenario in which the secondary neutron star never collapsed to a black hole.
Abstract Copyright:
© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
gravitational waves - stars: neutron - black hole - neutron star mergers
Simbad objects:
6
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