Studying the onset of deconfinement with multi-messenger astronomy of neutron stars. (arXiv:2012.15785v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Blaschke_D/0/1/0/all/0/1">David Blaschke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cierniak_M/0/1/0/all/0/1">Mateusz Cierniak</a>
With the first multi-messenger observation of a binary neutron star merger
(GW170817) new constraints became available for masses and radii of neutron
stars. We introduce a class of hybrid EoS that fulfils all these constraints
and predicts a region in the mass-radius diagram that could be populated only
by hybrid neutron stars with quark matter cores. A confirmation of this
conjecture would be provided when the NICER radius measurement for the
high-mass pulsar PSR J0740+6620 yields a radius less than 11 km. Would this
radius measurement yield a result in excess of 12 km, this would allow for
both, a purely hadronic and a hybrid nature of this star. In the latter case
the maximum mass could reach $2.6~M_odot$ so that the lighter object in the
asymmetric binary merger GW190814 could have been a hybrid star. We demonstrate
that this high mass can be compatible with an early onset of deconfinement at
star masses below $1~M_odot$ and the occurrence of low-mass twin stars. In
such a case the remnant of GW170817 could be a long-lived hypermassive pulsar.
With the first multi-messenger observation of a binary neutron star merger
(GW170817) new constraints became available for masses and radii of neutron
stars. We introduce a class of hybrid EoS that fulfils all these constraints
and predicts a region in the mass-radius diagram that could be populated only
by hybrid neutron stars with quark matter cores. A confirmation of this
conjecture would be provided when the NICER radius measurement for the
high-mass pulsar PSR J0740+6620 yields a radius less than 11 km. Would this
radius measurement yield a result in excess of 12 km, this would allow for
both, a purely hadronic and a hybrid nature of this star. In the latter case
the maximum mass could reach $2.6~M_odot$ so that the lighter object in the
asymmetric binary merger GW190814 could have been a hybrid star. We demonstrate
that this high mass can be compatible with an early onset of deconfinement at
star masses below $1~M_odot$ and the occurrence of low-mass twin stars. In
such a case the remnant of GW170817 could be a long-lived hypermassive pulsar.
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