The Masses and Spins of Neutron Stars and Stellar-Mass Black Holes

Abstract

Stellar-mass black holes and neutron stars represent extremes in gravity, density, and magnetic fields. They therefore serve as key objects in the study of multiple frontiers of physics. In addition, their origin (mainly in core-collapse supernovae) and evolution (via accretion or, for neutron stars, magnetic spindown and reconfiguration) touch upon multiple open issues in astrophysics. In this review, we discuss current mass and spin measurements and their reliability for neutron stars and stellar-mass black holes, as well as the overall importance of spins and masses for compact object astrophysics. Current masses are obtained primarily through electromagnetic observations of binaries, although future microlensing observations promise to enhance our understanding substantially. The spins of neutron stars are straightforward to measure for pulsars, but the birth spins of neutron stars are more difficult to determine. In contrast, even the current spins of stellar-mass black holes are challenging to measure. As we discuss, major inroads have been made in black hole spin estimates via analysis of iron lines and continuum emission, with reasonable agreement when both types of estimate are possible for individual objects, and future X-ray polarization measurements may provide additional independent information. We conclude by exploring the exciting prospects for mass and spin measurements from future gravitational wave detections, which are expected to revolutionize our understanding of strong gravity and compact objects.

97 pages, 5 figures, solicited review for Physics Reports

References in corpus (52)

• Shapiro delay measurement of a two solar mass neutron star
• A Massive Pulsar in a Compact Relativistic Binary
• Tests of general relativity from timing the double pulsar
• Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• Constraining Black Hole Spin Via X-ray Spectroscopy
• Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes
• Global General Relativistic MHD Simulation of a Tilted Black-Hole Accretion Disk
• Pulsating White Dwarf Stars and Precision Asteroseismology
• Merger of binary neutron stars to a black hole: Disk mass, short gamma-ray bursts, and quasinormal mode ringing
• A Debris Disk Around An Isolated Young Neutron Star
• A 15.65 solar mass black hole in an eclipsing binary in the nearby spiral galaxy Messier 33
• Black Hole-Neutron Star Mergers: Disk Mass Predictions
• Formation of millisecond pulsars with CO white dwarf companions - II. Accretion, spin-up, true ages and comparison to MSPs with He white dwarf companions
• Quasar Accretion Disks Are Strongly Inhomogeneous
• Testing Accretion Disk Theory in Black Hole X-ray Binaries
• Broad iron K-alpha emission lines as a diagnostic of black hole spin
• Fully General Relativistic Simulations of Black Hole-Neutron Star Mergers
• Evolving black hole-neutron star binaries in general relativity using pseudospectral and finite difference methods
• Relativistic Simulations of Black Hole-Neutron Star Mergers: Effects of black-hole spin
• Relativistic iron emission lines in neutron star low-mass X-ray binaries as probes of neutron star radii
• Discovery of coherent millisecond X-ray pulsations in Aql X-1
• A Determination of the Spin of the Black Hole Primary in LMC X-1
• A systematic look at the Very High and Low/Hard state of GX 339-4: Constraining the black hole spin with a new reflection model
• Improved Mass and Radius Constraints for Quiescent Neutron Stars in Omega Cen and NGC 6397
• Warp diffusion in accretion discs: a numerical investigation
• Merger of black hole and neutron star in general relativity: Tidal disruption, torus mass, and gravitational waves
• Merger of black hole-neutron star binaries in full general relativity
• Gravitational-Wave Astronomy with Inspiral Signals of Spinning Compact-Object Binaries
• Black hole-neutron star mergers: effects of the orientation of the black hole spin
• Merger of black hole-neutron star binaries: nonspinning black hole case
• The coherence of kHz quasi-periodic oscillations in the X-rays from accreting neutron stars
• Mergers of Magnetized Neutron Stars with Spinning Black Holes: Disruption, Accretion and Fallback
• Initial Measurements of Black Hole Spin in GX 339-4 from Suzaku Spectroscopy
• Evidence of a Broad Relativistic Iron Line from the Neutron Star Low-Mass X-ray Binary Serpens X-1
• A model for the waveform behavior of accreting millisecond pulsars: Nearly aligned magnetic fields and moving emission regions
• Where is the Radiation Edge in Magnetized Black Hole Accretion discs?
• On the maximum amplitude and coherence of the kilohertz quasi-periodic oscillations in low-mass X-ray binaries
• General relativistic simulations of black hole-neutron star mergers: Effects of tilted magnetic fields
• The Burst Spectra of EXO 0748-676 during a Long 2003 XMM-Newton Observation
• Discovery of a Thorne-Zytkow object candidate in the Small Magellanic Cloud
• Rotational evolution of young pulsars due to superfluid decoupling
• Reflection From the Strong Gravity Regime in a z=0.658 Gravitationally Lensed-Quasar
• Alignment Timescale of the Microquasar GRO J1655-40
• Supporting evidence for the signature of the innermost stable circular orbit in Rossi X-ray data from 4U1636-536
• Parameter estimation for signals from compact binary inspirals injected into LIGO data
• Diskoseismology and QPOs Confront Black Hole Spin
• The Effect of a Time-Varying Accretion Disk Size on Quasar Microlensing Light Curves
• Eccentric Binary Millisecond Pulsars
• X-ray Polarization from Black Holes: GEMS Scientific White Paper
• The Eccentric Binary Millisecond Pulsar in NGC 1851
• Determining the spin of two stellar-mass black holes from disk reflection signatures

Cited by in corpus (91)

• GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run
• GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing Run
• Observation of gravitational waves from two neutron star-black hole coalescences
• GW190412: Observation of a Binary-Black-Hole Coalescence with Asymmetric Masses
• Gravitational wave searches for ultralight bosons with LIGO and LISA
• Distinguishing Spin-Aligned and Isotropic Black Hole Populations With Gravitational Waves
• Cygnus X-1 contains a 21-solar mass black hole -- implications for massive star winds
• Observational Constraints on Black Hole Spin
• Stellar structure models in modified theories of gravity: lessons and challenges
• Black hole superradiance of self-interacting scalar fields
• Upper limits on the rates of binary neutron star and neutron-star--black-hole mergers from Advanced LIGO's first observing run
• Gravitational waves and mass ejecta from binary neutron star mergers: Effect of the mass-ratio
• Hierarchical black hole mergers in young, globular and nuclear star clusters: the effect of metallicity, spin and cluster properties
• Impact of Massive Binary Star and Cosmic Evolution on Gravitational Wave Observations I: Black Hole-Neutron Star Mergers
• Populating the upper black hole mass gap through stellar collisions in young star clusters
• Exploring the Lower Mass Gap and Unequal Mass Regime in Compact Binary Evolution
• Spin Evolution of Stellar-mass Black Hole Binaries in Active Galactic Nuclei
• Black hole genealogy: Identifying hierarchical mergers with gravitational waves
• Black hole formation and fallback during the supernova explosion of a $40{\mathrm{M}}_{\odot }$ star
• Stellar-mass black holes in young massive and open stellar clusters IV: updated stellar-evolutionary and black hole spin models and comparisons with the LIGO-Virgo O1/O2 merger-event data
• Characterizing the continuous gravitational-wave signal from boson clouds around Galactic isolated black holes
• The Low Effective Spin of Binary Black Holes and Implications for Individual Gravitational-Wave Events
• The Most Massive Binary Black Hole Detections and the Identification of Population Outliers
• Astrophysics and cosmology with a decihertz gravitational-wave detector: TianGO
• Formation channels of single and binary stellar-mass black holes
• The spins of compact objects born from helium stars in binary systems
• Apples and Oranges: Comparing black holes in X-ray binaries and gravitational-wave sources
• Exploring Features in the Binary Black Hole Population
• An alternative interpretation of GW190412 as a binary black hole merger with a rapidly spinning secondary
• The Effect of Supernova Convection On Neutron Star and Black Hole Masses
• You Can't Always Get What You Want: The Impact of Prior Assumptions on Interpreting GW190412
• Kilonova Emission From Black Hole-Neutron Star Mergers. II. Luminosity Function and Implications for Target-of-opportunity Observations of Gravitational-wave Triggers and Blind Searches
• SuperRad: Modeling the black hole superradiance gravitational waveform
• Wind mass-loss rates of stripped stars inferred from Cygnus X-1
• A New Spin on an Old Black Hole: NuSTAR Spectroscopy of EXO 1846-031
• VAMANA: Modeling Binary Black Hole Population with Minimal Assumptions
• Template Bank for Compact Binary Coalescence Searches in Gravitational Wave Data: A General Geometric Placement Algorithm
• Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift During the LIGO-Virgo Run O3b
• Binary neutron star mergers in Einstein-scalar-Gauss-Bonnet gravity
• Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift During the LIGO-Virgo Run O3a
• NuSTAR Observations of the Black Hole GS 1354-645: Evidence of Rapid Black Hole Spin
• GW200115: a non-spinning black hole -- neutron star merger
• Tidal Spin-up of Black Hole Progenitor Stars
• GW241011 and GW241110: Exploring Binary Formation and Fundamental Physics with Asymmetric, High-Spin Black Hole Coalescence
• Impact of extreme spins and mass ratios on the post-merger observables of high-mass binary neutron stars
• Black Hole Spin in X-ray Binaries: Giving Uncertainties an $f$
• Looking for the parents of LIGO's black holes
• The X-ray binary population in the Galactic Center revealed through multi-decade observations
• Models of high-frequency quasi-periodic oscillations and black hole spin estimates in Galactic microquasars
• Spin and Accretion Rate Dependence of Black Hole X-Ray Spectra
• Modeling uncertainties in X-ray reflection spectroscopy measurements II: Impact of the radiation from the plunging region
• The Gravitational Wave Universe Toolbox: A software package to simulate observation of the Gravitational Wave Universe with different detectors
• Distinguishing double neutron star from neutron star-black hole binary populations with gravitational wave observations
• The Missing Link Between Black Holes in High-Mass X-ray Binaries and Gravitational-Wave Sources: Observational Selection Effects
• Formation of low-spinning 100 Msun black holes
• Evolution of Spin Period and Magnetic Field of the Crab Pulsar: Decay of the Braking Index by the Particle Wind Flow Torque
• Singularity-free black holes in conformal gravity: new observational constraints
• Rapid population synthesis of black-hole high-mass X-ray binaries: implications for binary stellar evolution
• Common origin for black holes in both high mass X-ray binaries and gravitational-wave sources
• Rapidly rotating neutron star progenitors
• Universal behavior of compact star based upon gravitational binding energy
• Testing Blandford-Znajek mechanism in black hole hyperaccretion flows for long-duration gamma-ray bursts
• Twisted light, a new tool for General Relativity and beyond
• Neutron Star QPOs from Oscillating, Precessing Hot, Thick Flow
• Accretion of matter and spectra of Binary X-ray sources in Massive Gravity
• A geometric origin for quasi-periodic oscillations in black hole X-ray binaries
• Implications for the hierarchy problem, inflation and geodesic motion from fiber fabric of spacetime
• XRB continuum fitting with sensitive high energy X-ray detectors
• Correlations between the frequencies of twin kHz QPOs and spins of neutron stars in LMXBs
• On the large apparent black hole spin-orbit misalignment angle in GW200115
• A Spectroscopic Angle on Central Engine Size Scales in Accreting Neutron Stars
• Natal kicks of compact objects
• The Black Hole Candidate Swift J1728.9$-$3613 and the Supernova Remnant G351.9$-$0.9
• Misaligned Spin Merging Black Holes in Modified Gravity (MOG)
• Reflecting on naked singularities: iron line fitting as a probe of the cosmic censorship conjecture
• X-ray spectropolarimetric characterization of the Z-source GX 340+0 in the normal branch
• Null Gravitational Redshift by a Reissner-Nordström Black Hole in the Strong Field Limit
• First joint observation by the underground gravitational-wave detector, KAGRA, with GEO600
• Binary X-ray sources in massive Brans-Dicke gravity
• On Ultra-long Period (53.8 min) Pulsar ASKAP J1935+2148: Coherent Radio Emission Triggered by Local Superstrong Magnetic Reconnection
• Neutron star under homotopy perturbation method
• Early evolution of newly born proto-neutron stars
• IXPE view of the Sco-like source GX 349+2 in the normal branch
• Estimating the black hole mass of NGC1313 X-1 based on the spectral and timing properties
• Detectability and Parameter Estimation for Einstein Telescope Configurations with GWJulia
• On the Calculation of the Fe K-alpha Line Emissivity of Black Hole Accretion Disks
• Where are Gaia's small black holes?
• Interactions of Type I X-ray Bursts with Thin Accretion Discs
• Spin-induced motion in black hole spacetime
• The Spin and Orientation of the Black Hole in XTE J1908$+$094
• Impact of tides on non-coplanar orbits of progenitors of high-mass X-ray binaries