Inferring the neutron star maximum mass and lower mass gap in neutron star-black hole systems with spin

Abstract

Gravitational-wave (GW) detections of merging neutron star-black hole (NSBH) systems probe astrophysical neutron star (NS) and black hole (BH) mass distributions, especially at the transition between NS and BH masses. Of particular interest are the maximum NS mass, minimum BH mass, and potential mass gap between them. While previous GW population analyses assumed all NSs obey the same maximum mass, if rapidly spinning NSs exist, they can extend to larger maximum masses than nonspinning NSs. In fact, several authors have proposed that the $\sim 2.6M_{\odot }$ object in the event GW190814 -- either the most massive NS or least massive BH observed to date -- is a rapidly spinning NS. We therefore infer the NSBH mass distribution jointly with the NS spin distribution, modeling the NS maximum mass as a function of spin. Using 4 LIGO-Virgo NSBH events including GW190814, if we assume that the NS spin distribution is uniformly distributed up to the maximum (breakup) spin, we infer the maximum non-spinning NS mass is $2.7_{-0.4}^{+0.5}{M}_{\odot }$ (90\% credibility), while assuming only nonspinning NSs, the NS maximum mass must be $>2.53M_{\odot }$ (90\% credibility). The data support the mass gap's existence, with a minimum BH mass at $5.4_{-1.0}^{+0.7}{M}_{\odot }$. With future observations, under simplified assumptions, 150 NSBH events may constrain the maximum nonspinning NS mass to $\pm 0.02M_{\odot }$, and we may even measure the relation between the NS spin and maximum mass entirely from GW data. If rapidly rotating NSs exist, their spins and masses must be modeled simultaneously to avoid biasing the NS maximum mass.

17 pages, 13 figures. Accepted to ApJ, in press

References in corpus (31)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Advanced Virgo: a 2nd generation interferometric gravitational wave detector
• A Massive Pulsar in a Compact Relativistic Binary
• Advanced LIGO
• GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run
• GW190814: Gravitational Waves from the Coalescence of a 23 M${}_{\odot }$ Black Hole with a 2.6 M${}_{\odot }$ Compact Object
• Constraining the Maximum Mass of Neutron Stars From Multi-Messenger Observations of GW170817
• Observation of gravitational waves from two neutron star-black hole coalescences
• Accurate Determination of the Neutron Skin Thickness of ${}^{208}$Pb through Parity-Violation in Electron Scattering
• The LIGO Open Science Center
• Impact of the PSR J0740+6620 radius constraint on the properties of high-density matter
• Where are LIGO's Big Black Holes?
• Constraining the Neutron Star Mass-Radius Relation and Dense Matter Equation of State with NICER. I. The Millisecond Pulsar X-ray Data Set
• A lower bound on the maximum mass if the secondary in GW190814 was once a rapidly spinning neutron star
• Model-independent inference on compact-binary observations
• The Mass Distribution of Neutron Stars in Gravitational-wave Binaries
• Bridging the Gap: Categorizing Gravitational-Wave Events at the Transition Between Neutron Stars and Black Holes
• Does Matter Matter? Using the mass distribution to distinguish neutron stars and black holes
• Modelling Neutron Star-Black Hole Binaries: Future Pulsar Surveys and Gravitational Wave Detectors
• An alternative interpretation of GW190412 as a binary black hole merger with a rapidly spinning secondary
• A Population-Informed Mass Estimate for Pulsar J0740+6620
• Hierarchical Inference of Binary Neutron Star Mass Distribution and Equation of State with Gravitational Waves
• Heavy double neutron stars: birth, mid-life and death
• GW200115: a non-spinning black hole -- neutron star merger
• Probing Extremal Gravitational-Wave Events with Coarse-Grained Likelihoods
• Inferring the maximum and minimum mass of merging neutron stars with gravitational waves
• Population Properties of Gravitational-Wave Neutron Star--Black Hole Mergers
• Final compact remnants in core-collapse supernovae from 20 to 40 $M_{\odot }$: the lower mass gap
• Unmodelled Clustering Methods for Gravitational Wave Populations of Compact Binary Mergers
• The effect of spin mismodeling on gravitational-wave measurements of the binary neutron star mass distribution
• Population properties of neutron stars in the coalescing compact binaries

Cited by in corpus (17)

• The Science of the Einstein Telescope
• No peaks without valleys: The stable mass transfer channel for gravitational-wave sources in light of the neutron star-black hole mass gap
• A light strange star in the remnant HESS J1731-347: minimal consistency checks
• Triage of the Gaia DR3 astrometric orbits. I. A sample of binaries with probable compact companions
• Population properties and multimessenger prospects of neutron star-black hole mergers following GWTC-3
• Potential Subpopulations and Assembling Tendency of the Merging Black Holes
• Constraints on the Cosmological Coupling of Black Holes from the Globular Cluster NGC 3201
• Constraints on the cosmological coupling of black holes from Gaia
• Gravitational wave populations and cosmology with neural posterior estimation
• Structure in the speed of sound: from neutron stars to heavy-ion collisions
• Constraints on cosmologically coupled black holes from gravitational wave observations and minimal formation mass
• Mass Distribution and Maximum Mass of Neutron Stars: Effects of Orbital Inclination Angle
• Novel Scalings of Neutron Star Properties from Analyzing Dimensionless Tolman--Oppenheimer--Volkoff Equations
• Formation of GW230529 from Isolated Binary Evolution
• An Overview of Compact Star Populations and Some of Its Open Problems
• Compact object populations over cosmic time II. Compact object merger rates and masses over redshift from varying initial conditions
• Where are Gaia's small black holes?