The Radius of PSR J0740+6620 from NICER and XMM-Newton Data

Abstract

PSR J0740$+$6620 has a gravitational mass of $2.08\pm 0.07M_{\odot }$, which is the highest reliably determined mass of any neutron star. As a result, a measurement of its radius will provide unique insight into the properties of neutron star core matter at high densities. Here we report a radius measurement based on fits of rotating hot spot patterns to Neutron Star Interior Composition Explorer (NICER) and X-ray Multi-Mirror (XMM-Newton) X-ray observations. We find that the equatorial circumferential radius of PSR J0740$+$6620 is $13.7_{-1.5}^{+2.6}$ km (68%). We apply our measurement, combined with the previous NICER mass and radius measurement of PSR J0030$+$0451, the masses of two other $\sim 2M_{\odot }$ pulsars, and the tidal deformability constraints from two gravitational wave events, to three different frameworks for equation of state modeling, and find consistent results at $\sim 1.5-3$ times nuclear saturation density. For a given framework, when all measurements are included the radius of a $1.4M_{\odot }$ neutron star is known to $\pm 4$% (68% credibility) and the radius of a $2.08M_{\odot }$ neutron star is known to $\pm 5$%. The full radius range that spans the $\pm 1\sigma$ credible intervals of all the radius estimates in the three frameworks is $12.45\pm 0.65$ km for a $1.4M_{\odot }$ neutron star and $12.35\pm 0.75$ km for a $2.08M_{\odot }$ neutron star.

49 pages, 16 figures, submitted to The Astrophysical Journal Letters

References in corpus (50)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Shapiro delay measurement of a two solar mass neutron star
• A Massive Pulsar in a Compact Relativistic Binary
• GW190814: Gravitational Waves from the Coalescence of a 23 M${}_{\odot }$ Black Hole with a 2.6 M${}_{\odot }$ Compact Object
• PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter
• A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation
• GW190425: Observation of a Compact Binary Coalescence with Total Mass $\sim 3.4M_{\odot }$
• Neutron Star Observations: Prognosis for Equation of State Constraints
• Tidal Love numbers of neutron stars
• Constraining the Maximum Mass of Neutron Stars From Multi-Messenger Observations of GW170817
• Relativistic theory of tidal Love numbers
• Accurate Determination of the Neutron Skin Thickness of ${}^{208}$Pb through Parity-Violation in Electron Scattering
• GW170817: Joint Constraint on the Neutron Star Equation of State from Multimessenger Observations
• Implications of PREX-II on the equation of state of neutron-rich matter
• Nonparametric constraints on neutron star matter with existing and upcoming gravitational wave and pulsar observations
• How well do we know the neutron-matter equation of state at the densities inside neutron stars? A Bayesian approach with correlated uncertainties
• A statistical test for Nested Sampling algorithms
• Constraining the dense matter equation of state with joint analysis of NICER and LIGO/Virgo measurements
• Reconstructing the neutron-star equation of state with gravitational-wave detectors from a realistic population of inspiralling binary neutron stars
• Neutron star mass and radius measurements from atmospheric model fits to X-ray burst cooling tail spectra
• Spectral Representations of Neutron-Star Equations of State
• Nonparametric Inference of Neutron Star Composition, Equation of State, and Maximum Mass with GW170817
• Tidal Deformation and Dissipation of Rotating Black Holes
• Constraining the Neutron Star Mass-Radius Relation and Dense Matter Equation of State with NICER. II. Emission from Hot Spots on a Rapidly Rotating Neutron Star
• Limiting masses and radii of neutron stars and their implications
• Spinning Black Holes Fall in Love
• Revisiting the lower bound on tidal deformability derived by AT 2017gfo
• Tidal Love Numbers of Kerr Black Holes
• Direct Astrophysical Tests of Chiral Effective Field Theory at Supranuclear Densities
• Quarkyonic Matter Equation of State in Beta-Equilibrium
• Constraints on Neutron Star Properties from X-ray Observations of Millisecond Pulsars
• Nested Sampling Methods
• PSR J0030+0451, GW170817 and the nuclear data: joint constraints on equation of state and bulk properties of neutron stars
• Bayesian Inference of the Symmetry Energy of Super-Dense Neutron-Rich Matter from Future Radius Measurements of Massive Neutron Stars
• Towards mitigation of apparent tension between nuclear physics and astrophysical observations by improved modeling of neutron star matter
• Equation of state constraints from nuclear physics, neutron star masses, and future moment of inertia measurements
• Constraints on the maximum mass of neutron stars with a quark core from GW170817 and NICER PSR J0030+0451 data
• Bayesian inference of dense matter EOS encapsulating a first-order hadron-quark phase transition from observables of canonical neutron stars
• Constraining the Neutron Star Mass--Radius Relation and Dense Matter Equation of State with NICER. III. Model Description and Verification of Parameter Estimation Codes
• Constraints on the Symmetry Energy from PREX-II in the Multimessenger Era
• Diffusive nuclear burning in cooling simulations and application to new temperature data of the Cassiopeia A neutron star
• Curvature-slope correlation of nuclear symmetry energy and its imprints on the crust-core transition, radius and tidal deformability of canonical neutron stars
• Implications of Feebly Interacting Dark Sector on Neutron Star Properties and Constraints from GW170817
• The special point on the hybrid star mass--radius diagram and its multi--messenger implications
• Parameter estimation for strong phase transitions in supranuclear matter using gravitational-wave astronomy
• Constraints on the muon fraction and density profile in neutron stars
• Magnetospheric return-current-heated atmospheres of rotation-powered millisecond pulsars
• Atmospheric Structure and Radiation Pattern for Neutron-Star Polar Caps Heated by Magnetospheric Return Currents
• Studying the parameters of the extended $\sigma$-$\omega$ model for neutron star matter
• The effect of diffusive nuclear burning in neutron star envelopes on cooling in accreting systems

Cited by in corpus (249)

• GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing Run
• A NICER View of the Massive Pulsar PSR J0740+6620 Informed by Radio Timing and XMM-Newton Spectroscopy
• Refined Mass and Geometric Measurements of the High-Mass PSR J0740+6620
• Constraining Neutron-Star Matter with Microscopic and Macroscopic Collisions
• On the Sound Speed in Neutron Stars
• Dense Nuclear Matter Equation of State from Heavy-Ion Collisions
• How perturbative QCD constrains the Equation of State at Neutron-Star densities
• Bosonic Dark Matter in Neutron Stars and its Effect on Gravitational Wave Signal
• Multimessenger constraints for ultra-dense matter
• POSYDON: A General-Purpose Population Synthesis Code with Detailed Binary-Evolution Simulations
• Trace anomaly as signature of conformality in neutron stars
• Searches for Continuous-Wave Gravitational Radiation
• Ab-initio QCD calculations impact the inference of the neutron-star-matter equation of state
• Upper Limit on the QCD Axion Mass from Isolated Neutron Star Cooling
• The Radius of PSR J0740+6620 from NICER with NICER Background Estimates
• The MeerKAT Pulsar Timing Array: First Data Release
• Heavy Baryons in Compact Stars
• Reaching percolation and conformal limits in neutron stars
• A Detailed Examination of Astrophysical Constraints on the Symmetry Energy and the Neutron Skin of ${}^{208}$Pb with Minimal Modeling Assumptions
• Constraining bosonic asymmetric dark matter with neutron star mass-radius measurements
• Impact of PREX-II and combined Radio/NICER/XMM-Newton's mass-radius measurement of PSRJ0740+6620 on the dense matter equation of state
• Extreme Matter meets Extreme Gravity: Ultra-heavy neutron stars with crossovers and first-order phase transitions
• The Parkes pulsar timing array second data release: Timing analysis
• Bayesian analysis of neutron-star properties with parameterized equations of state: the role of the likelihood functions
• Decoding the Density Dependence of the Nuclear Symmetry Energy
• Merger and post-merger of binary neutron stars with a quark-hadron crossover equation of state
• Implications of NICER for neutron star matter: the QHC21 equation of state
• An updated nuclear-physics and multi-messenger astrophysics framework for binary neutron star mergers
• Dark matter admixed neutron star properties in the light of X-ray pulse profile observations
• Inference of the sound speed and related properties of neutron stars
• Bosonic Dark Matter in Light of the NICER Precise Mass-Radius Measurements
• Holographic modeling of nuclear matter and neutron stars
• Relativistic hybrid stars in light of the NICER PSR J0740+6620 radius measurement
• Core-collapse supernova simulations and the formation of neutron stars, hybrid stars, and black holes
• Perturbative QCD and the Neutron Star Equation of State
• The effects of self-interacting bosonic dark matter on neutron star properties
• Plausible presence of new state in neutron stars with masses above $0.98M_{\mathrm{TOV}}$
• Dark Matter or Regular Matter in Neutron Stars? How to tell the difference from the coalescence of compact objects
• Investigating Signatures of Phase Transitions in Neutron-Star Cores
• Black hole-neutron star mergers are unlikely multi-messenger sources
• Impact of large-mass constraints on the properties of neutron stars
• Spanning the full range of neutron star properties within a microscopic description
• Uncertainty limits on neutron star radius measurements with gravitational waves
• The slope, the hill, the drop, and the swoosh: Learning about the nuclear matter equation of state from the binary Love relations
• Second release of the CoRe database of binary neutron star merger waveforms
• Relativistic mean-field theories for neutron-star physics based on chiral effective field theory
• Impacts of dark matter on the $f$-mode oscillation of hyperon star
• Impact of the equation of state on $f$- and $p$- mode oscillations of neutron stars
• Building a realistic neutron star from holography
• Imposing multi-physics constraints at different densities on the Neutron Star Equation of State
• Probing the incompressibility of nuclear matter at ultra-high density through the prompt collapse of asymmetric neutron star binaries
• Sensitivity of Au+Au collisions to the symmetric nuclear matter equation of state at 2 -- 5 nuclear saturation densities
• Resolving The Peak Of The Black Hole Mass Spectrum
• Horizons: Nuclear Astrophysics in the 2020s and Beyond
• Multi-physics constraints at different densities to probe nuclear symmetry energy in hyperonic neutron stars
• Bayesian model-selection of neutron star equation of state using multi-messenger observations
• Constraining scalar-tensor theories by neutron star-balck hole gravitational wave events
• Tidal Love Numbers of Novel and Admixed Celestial Objects
• No Detectable Kilonova Counterpart is Expected for O3 Neutron Star-Black Hole Candidates
• A Bayesian inference of relativistic mean-field model for neutron star matter from observation of NICER and GW170817/AT2017gfo
• Hierarchical Inference of Binary Neutron Star Mass Distribution and Equation of State with Gravitational Waves
• Role of vector self-interaction in Neutron Star properties
• Quark formation and phenomenology in binary neutron-star mergers using V-QCD
• Dense and Hot QCD at Strong Coupling
• Tidal Deformabilities of Neutron Stars in scalar-Gauss-Bonnet Gravity and Their Applications to Multimessenger Tests of Gravity
• Astrophysical implications on hyperon couplings and hyperon star properties with relativistic equations of states
• Peaks of sound velocity in two color dense QCD: quark saturation effects and semishort range correlations
• Simultaneous Inference of Neutron Star Equation of State and the Hubble Constant with a Population of Merging Neutron Stars
• Nucleonic metamodelling in light of multimessenger, PREX-II and CREX data
• EoS for hot neutron stars
• Large and massive neutron stars: Implications for the sound speed in dense QCD
• Probing neutron-star matter in the lab: similarities and differences between binary mergers and heavy-ion collisions
• Impact of NICER's Radius Measurement of PSR J0740+6620 on Nuclear Symmetry Energy at Suprasaturation Densities
• A Neutron Star is born
• $g$-modes of neutron stars with hadron-to-quark crossover transitions
• Constraints on strong phase transitions in neutron stars
• Benchmark calculations of infinite neutron matter with realistic two- and three-nucleon potentials
• Delta-resonances and hyperons in proto-neutron stars and merger remnants
• Universal relations for rapidly rotating cold and hot hybrid star
• Bayesian inference of signatures of hyperons inside neutron stars
• Confirming the existence of twin stars in a NICER way
• Quark stars with 2.6 $M_{\odot }$ in a non-minimal geometry-matter coupling theory of gravity
• Holographic approach to compact stars and their binary mergers
• GRMHD Simulations of Accreting Neutron Stars with Non-Dipole Fields
• IXPE Detection of Polarized X-rays from Magnetars and Photon Mode Conversion at QED Vacuum Resonance
• Low-energy nuclear physics and global neutron star properties
• Bayesian Inference of the Dense Matter Equation of State built upon Covariant Density Functionals
• Constraints on the curvature of nuclear symmetry energy from recent astronomical data within the KIDS framework
• On the moment of inertia of PSR J0737-3039 A from LIGO/Virgo and NICER
• A model-agnostic analysis of hybrid stars with reactive interfaces
• Interacting $ud$ and $uds$ quark matter at finite densities and quark stars
• Holographic approach to transport in dense QCD matter
• Vector interactions inhibit quark-hadron mixed phases in neutron stars
• GW190814: Circumstantial Evidence for Up-Down Quark Star
• The baryon coupling scheme in an unified SU(3) and SU(6) symmetry formalism
• Nearly model-independent constraints on dense matter equation of state in a Bayesian approach
• PUSHing core-collapse supernovae to explosions in spherical symmetry V: Equation of state dependency of explosion properties, nucleosynthesis yields, and compact remnants
• Can fermion-boson stars reconcile multi-messenger observations of compact stars?
• Dark particle mass effects on neutron star properties from a short-range correlated hadronic model
• Binary neutron star mergers as a probe of quark-hadron crossover equations of state
• Quantifying modeling uncertainties when combining multiple gravitational-wave detections from binary neutron star sources
• Muons in the aftermath of neutron star mergers and their impact on trapped neutrinos
• Faint light of old neutron stars and detectability at the James Webb Space Telescope
• Is the compact object associated with HESS J1731-347 a strange quark star?
• Constraining Nuclear Symmetry Energy with Multi-messenger Resonant Shattering Flares
• Degeneracy in the inference of phase transitions in the neutron star equation of state from gravitational wave data
• Realistic neutron star models in $f(T)$ gravity
• Impact of massive neutron star radii on the nature of phase transitions in dense matter
• Hybrid neutron stars in the mass-radius diagram
• Quasi-equilibrium configurations of binary systems of dark matter admixed neutron stars
• Relativistic hybrid stars with sequential first-order phase transitions in light of multimessenger constraints
• Two first-order phase transitions in hybrid compact stars: higher-order multiplet stars, reaction modes and intermediate conversion speeds
• Hadron-quark Pasta Phase in Massive Neutron Stars
• Can we decipher the composition of the core of a neutron star?
• Scalarized neutron stars in massive scalar-tensor gravity: X-ray pulsars and tidal deformability
• Reconciling multi-messenger constraints with chiral symmetry restoration
• Bayesian inference of neutron-star observables based on effective nuclear interactions
• Ultracompact hybrid stars consistent with multimessenger astrophysics
• The uniform electron gas at high temperatures: \emph{ab initio} path integral Monte Carlo simulations and analytical theory
• Equation-of-state-insensitive measure of neutron star stiffness
• g-mode Oscillations in Neutron Stars with Hyperons
• Hyperonic neutron stars: reconciliation between nuclear properties and NICER and LIGO/VIRGO results
• Holographic QCD in the NICER era
• Testing the phase transition parameters inside neutron stars with the production of protons and lambdas in relativistic heavy-ion collisions
• Chiral condensates for neutron stars in hadron-quark crossover: from a parity doublet nucleon model to an NJL quark model
• Effect of color superconductivity on the mass of hybrid neutron stars in an effective model with pQCD asymptotics
• Characterizing the breakdown of quasi-universality in the post-merger gravitational waves from binary neutron star mergers
• Observing Supernova Neutrino Light Curves with Super-Kamiokande. II. Impact of the Nuclear Equation of State
• The Hadron-Quark Crossover in Neutron Star within Gaussian Process Regression Method
• Pasta properties of the neutron star within effective relativistic mean-field model
• Impacts of anomaly on nuclear and neutron star equation of state based on a parity doublet model
• Symmetry energy effects on the properties of hybrid stars
• From quarks and gluons to color superconductivity at supranuclear densities
• Crustal properties of a neutron star within an effective relativistic mean-field model
• Extended Tolman III and VII solutions in $f(\mathcal{R},T)$ gravity: Models for neutron stars and supermassive stars
• Hybrid star phenomenology from the properties of the special point
• Constraining neutron star properties with a new equation of state insensitive approach
• Constraints on the merging binary neutron star mass distribution and equation of state based on the incidence of jets in the population
• Models of binary neutron star remnants with tabulated equations of state
• Neutron star properties with careful parameterization in the (axial)vector meson extended linear sigma model
• Constraining mass, radius and tidal deformability of compact stars with axial wI modes: new universal relations including slow stable hybrid stars
• Constraining the equation of state of hybrid stars using recent information from multidisciplinary physics
• Exploring the effects of Delta Baryons in magnetars
• Exploring universal characteristics of neutron star matter with relativistic \textit{ab initio} equations of state
• Probing phase transition in neutron stars via the crust-core interfacial mode
• Non-strange quark stars within resummed QCD
• Compactness in the Thermal Evolution of Twin Stars
• Axion effects in the stability of hybrid stars
• Quantum Skyrmion crystals and the symmetry energy of dense matter
• A bag model of matter condensed by the strong interaction
• Magnetic-Field Induced Deformation in Hybrid Stars
• Effect of nucleon effective mass and symmetry energy on the neutrino mean free path in a neutron star
• Speed of sound in dense matter and two families of compact stars
• Needle in a Bayes Stack: a Hierarchical Bayesian Method for Constraining the Neutron Star Equation of State with an Ensemble of Binary Neutron Star Post-merger Remnants
• Speed of sound in dense strong-interaction matter
• ${}^1$S${}_0$ pairing gaps, chemical potential and entrainment matrix in superfluid neutron-star cores for the Brussels-Montreal functionals
• Rotating Love: The dynamical tides of spinning Newtonian stars
• Interface effects of quark matter: Light-quark nuggets and compact stars
• Speed of Sound for Hadronic and Quark Phases in a Magnetic Field
• Non-radial oscillations and global stellar properties of anisotropic compact stars using realistic equations of state
• Quarkyonic matter state of neutron stars
• Hubble constant and nuclear equation of state from kilonova spectro-photometric light curves
• Holographic cold dense matter constrained by neutron stars
• Gravitational radiation from thermal mountains on accreting neutron stars: sources of temperature non-axisymmetry
• Constraining free parameters of a color superconducting non-local Nambu-Jona-Lasinio model using Bayesian analysis of neutron stars mass and radius measurements
• Analytical expressions for pulse profile of neutron stars in plasma environments
• Constraints on the dense matter equation of state and neutron star properties from NICER's mass-radius estimate of PSR J0740+6620 and multimessenger observations
• Acceptability Conditions and Relativistic Anisotropic Generalized Polytropes
• Neutron Stars in Modified Teleparallel Gravity
• The relative contribution to heavy metals production from binary neutron star mergers and neutron star-black hole mergers
• $R^2$-gravity quark stars from perturbative QCD
• PNJL model at zero temperature: three-flavor case
• Tidal Deformability Doppelgangers: Implications of a low-density phase transition in the neutron star equation of state
• Baryonic dense matter in view of gravitational-wave observations
• Nonparametric Representation of Neutron Star Equation of State Using Variational Autoencoder
• Accretion onto black holes inside neutron stars with piecewise-polytropic equations of state: analytic and numerical treatments
• Relativistic correction to the r-mode frequency in light of multi-messenger constraints
• Effects of nuclear matter and composition in core-collapse supernovae and long-term proto-neutron star cooling
• Equation of state of neutron star matter and its warm extension with an interacting hadron resonance gas
• Effects of Onset of Phase Transition on Binary Neutron Star Mergers
• Detectability of Sub-Solar Mass Neutron Stars Through a Template Bank Search
• Detecting dense-matter phase transition signatures in neutron star mass-radius measurements as data anomalies using normalising flows
• How does dark matter affect compact star properties and high density constraints of strongly interacting matter
• Exploring the Fate of Stellar Core Collapse with Supernova Relic Neutrinos
• Revisiting the post-glitch relaxation of the 2000 Vela glitch with the neutron star equation of states in the Brueckner and relativistic Brueckner theories
• Holographic dense QCD in the Veneziano limit
• Hyperons, deconfinement and the speed of sound in neutron stars
• Rotating Hybrid Stars with Color-Flavor-Locked Quark Matter
• Standard cooling of rapidly rotating isolated neutron stars in 2D
• Realizing the potential of deep neural network for analyzing neutron star observables and dense matter equation of state
• (Anti)kaon condensation in strongly magnetized dense matter
• Hybrid stars may have an inverted structure
• Comparison of different relativistic models applied to dense nuclear matter
• Case for quarkyoniclike matter from a constituent quark model
• Incompressibility and Symmetry Energy of Neutron Star
• Exploring the Phase Diagram of V-QCD with Neutron Star Merger Simulations
• Fundamental physics with neutron stars
• Delineating chiral separation effect in two-color dense QCD
• Nuclear-Physics Multi-Messenger Astrophysics Constraints on the Neutron-Star Equation of State: Adding NICER's PSR J0740+6620 Measurement
• Hadron-quark phase transition in neutron star by combining the relativistic Brueckner-Hartree-Fock theory and Dyson-Schwinger equation approach
• A New Structure in the Deuteron
• The neutron star population in M28: a joint Chandra/GBT look at pulsar paradise
• Strange stars with a mirror-dark-matter core confronting with the observations of compact stars
• On the maximum compactness of neutron stars
• Structure of Stellar Remnants with Coupling to a Light Scalar
• Quark condensate and chiral symmetry restoration in neutron stars
• Selection Effects in Periodic X-ray Data from Maximizing Detection Statistics
• Equation of state in neutron stars and supernovae
• Constraining the Surface Curvature of an Anisotropic Neutron Star
• Hyperonization in compact stars
• Slowly rotating Tolman VII solution
• Simulating neutron stars with a flexible enthalpy-based equation of state parametrization in SpECTRE
• Accuracy of one-dimensional approximation in neutron star quasi-normal modes
• Crustal failure as a tool to probe hybrid stars
• Merger of a Neutron Star with a Black Hole: one-family vs. two-families scenario
• Modeling Neutron Star Matter in the Age of Multimessenger Astrophysics
• Conformality and percolation threshold in neutron stars
• Density dependence of symmetry energy and neutron skin thickness revisited using relativistic mean field models with nonlinear couplings
• Tidal Deformability as a Probe of Dark Matter in Neutron Stars
• Quark deconfinement in compact stars through sexaquark condensation
• Semi Universal relation to understand matter properties at neutron star interiors
• Modeling photometric variations due to a global inhomogeneity on an obliquely rotating star: application to lightcurves of white dwarfs
• Thermal impacts on the properties of nuclear matter and young neutron star
• Special point "trains" in the M-R diagram of hybrid stars
• The Impact of $f(\mathcal{G},T)$ Gravity on the Evolution of Cavity in the Cluster of Stars
• Neutrino propagation in the neutron star with uncertainties from nuclear, hadron, and particle physics
• Bayesian analysis of multimessenger M-R data with interpolated hybrid EoS
• Finite-temperature equation of state with hyperons
• Diquarkyonic matter: quarks, diquarks and baryons
• Correlation between the curvature and some properties of the neutron star
• Early deconfinement of asymptotically conformal color-superconducting quark matter in neutron stars
• Chiral condensates for neutron stars in hadron-quark crossover; from a parity doublet nucleon model to an NJL quark model
• Extremal Instability for Topological Black Holes
• Gravitational wave signatures of phase transition from hadronic to quark matter in isolated neutron stars and binaries
• Rapid Hierarchical Inference of Neutron Star Equation of State from multiple Gravitational Wave Observations of Binary Neutron Star Coalescences
• Influence of hyperon-hyperon interaction on the properties of neutron stars
• Modeling Neutron Star Oscillations in a Fixed General Relativistic Background Including Solid Crust Dynamics
• Equation of state for hot hyperonic neutron star matter
• Electrically charged supermassive twin stars
• Density functional approach to quark matter with confinement and color superconductivity
• Prospects for distinguishing dynamical tides in inspiralling binary neutron stars with third generation gravitational-wave detectors
• A new class of hybrid EoS with multiple critical endpoints for simulations of supernovae, neutron stars and their mergers
• Universal Relations for the Increase in the Mass and Radius of a Rotating Neutron Star
• Differentiating between sharp and smoother phase transitions in neutron stars
• Insights into the equation of state of neutron-rich matter since GW170817
• The nuclear matter density functional under the nucleonic hypothesis
• NICER view on holographic QCD
• Investigating the mass-ratio dependence of the prompt-collapse threshold with numerical-relativity simulations
• Hybrid stars with large strange quark cores