Merger of a Neutron Star with a Black Hole: one-family vs. two-families scenario

Abstract

A kilonova signal is generally expected after a Black Hole - Neutron Star merger. The strength of the signal is related to the equation of state of neutron star matter and it increases with the stiffness of the latter. The recent results obtained by NICER from the analyses of PSR J0740+6620 suggest a rather stiff equation of state and the expected kilonova signal is therefore strong, at least if the mass of the Black Hole does not exceed $\sim 10{\mathrm{M}}_{\odot }$ and if the adimensional spin parameter is not too small and the orbit is prograde. We compare the predictions obtained by considering equations of state of neutron star matter satisfying the most recent observations and assuming that only one family of compact stars exists with the results predicted in the two-families scenario. In the latter a soft hadronic equation of state produces very compact stellar objects while a rather stiff quark matter equation of state produces massive strange quark stars, satisfying NICER results. The expected kilonova signal in the two-families scenario is very weak: in particular the Hadronic Star - Black Hole merger produces a much weaker signal than in the one-family scenario because the hadronic equation of state is very soft. Moreover, according to the only existing simulation, the Strange Quark Star - Black Hole merger does not produce a kilonova signal because the amount of mass ejected is negligible. These predictions will be easily tested with the new generation of detectors if Black Holes with an adimensional spin parameter ${\chi }_{\mathrm{BH}}\gtrsim 0.2$ or a mass ${\mathrm{M}}_{\mathrm{BH}}\lesssim 4{\mathrm{M}}_{\odot }$ can be present in the merger.

arXiv comment8 pages, 5 figures. Significantly extended, published version

References in corpus (34)

• The equation of state for nucleon matter and neutron star structure
• GW170817: Measurements of Neutron Star Radii and Equation of State
• A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation
• GW190425: Observation of a Compact Binary Coalescence with Total Mass $\sim 3.4M_{\odot }$
• Masses, Radii, and Equation of State of Neutron Stars
• A NICER View of the Massive Pulsar PSR J0740+6620 Informed by Radio Timing and XMM-Newton Spectroscopy
• Composition and thermodynamics of nuclear matter with light clusters
• Observation of gravitational waves from two neutron star-black hole coalescences
• Compact Object Modeling with the StarTrack Population Synthesis Code
• Core-collapse supernova equations of state based on neutron star observations
• New constraints on radii and tidal deformabilities of neutron stars from GW170817
• Stringent constraints on neutron-star radii from multimessenger observations and nuclear theory
• The evolutionary roads leading to low effective spins, high black hole masses, and O1/O2 rates of LIGO/Virgo binary black holes
• Remnant baryon mass outside of the black hole after a neutron star-black hole merger
• Quark deconfinement and implications for the radius and the limiting mass of compact stars
• Neutron star mass and radius measurements from atmospheric model fits to X-ray burst cooling tail spectra
• Can very compact and very massive neutron stars both exist?
• Models of Kilonova/macronova emission from black hole-neutron star mergers
• Merger of black hole and neutron star in general relativity: Tidal disruption, torus mass, and gravitational waves
• Was GW190814 a black hole -- strange quark star system?
• Hierarchical Black-Hole Mergers in Multiple Systems: Constrain the Formation of GW190412, GW190814 and GW190521-like events
• Gravitational-wave astrophysics with effective-spin measurements: asymmetries and selection biases
• Are small radii of compact stars ruled out by GW170817/AT2017gfo?
• On the formation of GW190814
• Electromagnetic counterparts of black hole-neutron star mergers: dependence on the neutron star properties
• Merger of two neutron stars: predictions from the two-families scenario
• Black hole-neutron star mergers are unlikely multi-messenger sources
• Kilonova Detectability with Wide-Field Instruments
• Merger of compact stars in the two-families scenario
• No Detectable Kilonova Counterpart is Expected for O3 Neutron Star-Black Hole Candidates
• The swallowing of a quark star by a black hole
• The Radius of PSR J0740+6620 from NICER and XMM-Newton Data
• Why can hadronic stars convert into strange quark stars with larger radii
• Neutron star equation of state via gravitational wave observations

Cited by in corpus (4)

• The Science of the Einstein Telescope
• Long-duration Gamma-ray Burst and Associated Kilonova Emission from Fast-spinning Black Hole--Neutron Star Mergers
• Strangeness thermodynamic instabilities in hot and dense nuclear matter
• Explainable autoencoder for neutron star dense matter parameter estimation