Refined Neutron-Star Mass Determinations for Six Eclipsing X-Ray Pulsar Binaries

Abstract

We present an improved method for determining the mass of neutron stars in eclipsing X-ray pulsar binaries and apply the method to six systems, namely Vela X-1, 4U 1538-52, SMC X-1, LMC X-4, Cen X-3, and Her X-1. In previous studies to determine neutron star mass, the X-ray eclipse duration has been approximated analytically by assuming the companion star is spherical with an effective Roche lobe radius. We use a numerical code based on Roche geometry with various optimizers to analyze the published data for these systems, which we supplement with new spectroscopic and photometric data for 4U 1538-52. This allows us to model the eclipse duration more accurately and thus calculate an improved value for the neutron star mass. The derived neutron star mass also depends on the assumed Roche lobe filling factor beta of the companion star, where beta = 1 indicates a completely filled Roche lobe. In previous work a range of beta between 0.9 and 1.0 was usually adopted. We use optical ellipsoidal lightcurve data to constrain beta. We find neutron star masses of 1.77 +/- 0.08 M_{sun} for Vela X-1, 0.87 +/- 0.07 M_{sun} for 4U 1538-52 (eccentric orbit), 1.00 +/- 0.10 M_{sun} for 4U 1538-52 (circular orbit), 1.04 +/- 0.09 M_{sun} for SMC X-1, 1.29 +/- 0.05 M_{sun} for LMC X-4, 1.49 +/- 0.08 M_{sun} for Cen X-3, and 1.07 +/- 0.36 M_{sun} for Her X-1. We discuss the limits of the approximations that were used to derive the earlier mass determinations, and we comment on the implications our new masses have for observationally refining the upper and lower bounds of the neutron star mass distribution.

10 figures, accepted for publication in The Astrophysical Journal

References in corpus (5)

• Shapiro delay measurement of a two solar mass neutron star
• Evidence for a Massive Neutron Star from a Radial-Velocity Study of the Companion to the Black Widow Pulsar PSR B1957+20
• The Massive Pulsar PSR J1614-2230: Linking Quantum Chromodynamics, Gamma-ray Bursts, and Gravitational Wave Astronomy
• High variability in Vela X-1: giant flares and off states
• Determination of the mass of the neutron star in SMC X-1, LMC X-4 and Cen X-3 with VLT/UVES

Cited by in corpus (182)

• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• Masses, Radii, and Equation of State of Neutron Stars
• The Nuclear Equation of State and Neutron Star Masses
• Approximate Universal Relations for Neutron Stars and Quark Stars
• On the Mass Distribution and Birth Masses of Neutron Stars
• Strange star equation of state fits the refined mass measurement of 12 pulsars and predicts their radii
• Born-Infeld inspired modifications of gravity
• The Mass-Radius relation for Neutron Stars in $f(R)$ gravity
• Extreme neutron stars from Extended Theories of Gravity
• Maximal neutron star mass and the resolution of hyperon puzzle in modified gravity
• Evidence for a maximum mass cut-off in the neutron star mass distribution and constraints on the equation of state
• Cyclotron lines in highly magnetized neutron stars
• Early X-ray and optical afterglow of gravitational wave bursts from mergers of binary neutron stars
• Gravitational waves and mass ejecta from binary neutron star mergers: Effect of the mass-ratio
• The realistic models of relativistic stars in f(R) = R + alpha R^2 gravity
• Extended Gravity Description for the GW190814 Supermassive Neutron Star
• Study on anisotropic strange stars in $f(R,T)$ gravity: An embedding approach under simplest linear functional of matter-geometry coupling
• The ephemeris, orbital decay, and masses of 10 eclipsing HMXBs
• Anisotropic Compact stars in the Buchdahl model: A comprehensive study
• New Schwarzschild-like solutions in f(T) gravity through Noether symmetries
• Constraints on binary neutron star merger product from short GRB observations
• Exploring physical features of anisotropic strange stars beyond standard maximum mass limit in $f\left(R,\mathcal{T}\right)$ gravity
• Revisiting a fundamental test of the disc instability model for X-ray binaries
• When can gravitational-wave observations distinguish between black holes and neutron stars?
• On neutron stars in f(R) theories: small radii, large masses and large energy emitted in a merger
• Accretion-induced prompt black hole formation in asymmetric neutron star mergers, dynamical ejecta and kilonova signals
• Binary Neutron Stars with Generic Spin, Eccentricity, Mass ratio, and Compactness - Quasi-equilibrium Sequences and First Evolutions
• Formation of millisecond pulsars with CO white dwarf companions - I. PSR J1614-2230: Evidence for a neutron star born massive
• Modified TOV in gravity's rainbow: properties of neutron stars and dynamical stability conditions
• Gravitationally decoupled strange star model beyond standard maximum mass limit in Einstein-Gauss-Bonnet gravity
• Physical Characteristics and Maximum Allowable Mass of Hybrid Star in the Context of $f(Q)$ Gravity
• On the Induced Gravitational Collapse of a Neutron Star to a Black Hole by a Type Ib/c Supernova
• A new deterministic model of strange stars
• Magnetic Neutron Stars in f(R) gravity
• Non-trivial class of anisotropic compact stellar model in Rastall gravity
• Exploring physical properties of minimally deformed strange star model and constraints on maximum mass limit in $f(\mathcal{Q})$ gravity
• X-ray Binaries
• A new class of relativistic model of compact stars of embedding class I
• Relativistic Stars in dRGT Massive Gravity
• Modified Finch and Skea stellar model compatible with observational data
• Optical and Near Infrared Monitoring of the Black-Hole X-ray Binary GX 339-4 During 2002-2010
• Maximum gravitational mass $M_{\mathrm{TOV}}=2.25_{-0.07}^{+0.08}{M}_{\odot }$ inferred at about $3\%$ precision with multimessenger data of neutron stars
• Constraining values of bag constant for strange star candidates
• Stellar models with like--Tolman IV complexity factor
• The Black Hole Binary V4641 Sagitarii: Activity in Quiescence & Improved Mass Determinations
• Anisotropic Strange Star Model Beyond Standard Maximum Mass Limit by Gravitational Decoupling in $f(Q)$ Gravity
• Low Mass X-ray Binaries: The Effects of the Magnetic Braking Prescription
• On the formation of PSR J1640+2224: a neutron star born massive?
• Charged compact objects in the linear regime
• The mass-radius relation for neutron stars in $f(R)=R+\alpha R^2$ gravity: a comparison between purely metric and torsion formulations
• Dark Energy Stars in Tolman-Kuchowicz spacetime in the context of Einstein Gravity
• Stellar objects in the quadratic regime
• Angular Momentum Role in the Hypercritical Accretion of Binary-Driven Hypernovae
• Expansion of magnetic neutron stars in an energy (in)dependent spacetime
• The effect of $f(R,T)$ modified gravity on mass and radius of pulsar HerX1
• Formation of wind-captured discs in Supergiant X-ray binaries : consequences for Vela X-1 and Cygnus X-1
• Mass and radius formulas for low-mass neutron stars
• Maximum mass cutoff in the neutron star mass distribution and the prospect of forming supramassive objects in the double neutron star mergers
• Discovery of a Neutron Star Oscillation Mode During a Superburst
• Formation of Millisecond Pulsars from Intermediate- and Low-Mass X-ray Binaries
• Influence of three parameters on maximum mass and stability of strange star under linear $f(Q)-$action
• GRB 090618: The First Example of a Neutron Star Gravitational Collapse to a Black Hole Induced by a Type Ib/c Supernova
• Impact of Rastall gravity on mass, radius and sound speed of the pulsar PSR J0740+6620
• Relativistic stars in bigravity theory
• Revisiting the archetypical wind accretor Vela X-1 in depth -- A case study of a well-known X-ray binary and the limits of our knowledge
• Runaway OB Stars in the Small Magellanic Cloud: Dynamical Versus Supernova Ejections
• A Clumpy Stellar Wind and Luminosity-Dependent Cyclotron Line Revealed by The First Suzaku Observation of the High-Mass X-ray Binary 4U 1538-522
• Viable and Stable Compact Stellar Structures in $f(\mathcal{Q},\mathcal{T})$ Theory
• Equilibrium and stability of relativistic stars in extended theories of gravity
• A New Model for Strange Stars
• On stability of a neutron star system in Palatini gravity
• The accretion environment in Vela X-1 during a flaring period using XMM-Newton
• Anisotropic Quark Stars with an Interacting Quark Equation of State
• Compact stars with linear equation of state in isotropic coordinates
• Durgapal IV model in light of the minimal geometric deformation approach
• Pulse phase resolved spectroscopy of Vela X-1 with Suzaku
• Relativistic charged spheres: Compact stars, compactness and stable configurations
• An analytical anisotropic compact stellar model of embedding class I
• Confront $f(R,T)=\mathcal{R}+\beta T$ modified gravity with the massive pulsar PSR J0740+6620
• Quark stars with 2.6 $M_{\odot }$ in a non-minimal geometry-matter coupling theory of gravity
• X-ray irradiation of the winds in binaries with massive components
• The Swift-BAT monitoring reveals a long term decay of the cyclotron line energy in Vela X-1
• Mass/Radius Constraints on the Quiescent Neutron Star in M13 Using Hydrogen and Helium Atmospheres
• Observational discrimination of Eddington-inspired Born-Infeld gravity from general relativity
• Impact of extreme spins and mass ratios on the post-merger observables of high-mass binary neutron stars
• Physical Analysis of Spherical Stellar Structures in $f(\mathrm{Q},\mathrm{T})$ Theory
• Novel Model of an Ultra-stripped Supernova Progenitor of a Double Neutron Star
• Tolman IV fluid sphere in f(R, T) gravity
• An Ultra Low Mass and Small Radius Compact Object in 4U 1746-37?
• An Observationally-Derived Kick Distribution for Neutron Stars in Binary Systems
• The observed neutron star mass distribution as a probe of the supernova explosion mechanism
• Study of Compact Stars in $\mathcal{R}+\alpha \mathcal{A}$ Gravity
• Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with INTEGRAL
• Anisotropic magnetized neutron star
• Strange stars in $f(\mathcal{R})$ gravity Palatini formalism and gravitational wave echoes from them
• Relativistic isotropic stellar model in $f(R,T)$ gravity with Durgapal- IV Metric
• Anisotropic extension of Finch and Skea stellar model
• Stellar wind accretion and accretion disk formation: applications to neutron star high mass X-ray binaries
• The First NuSTAR Observation of 4U 1538-522: Updated Orbital Ephemeris and A Strengthened Case for an Evolving Cyclotron Line Energy
• Probing the stellar wind environment of Vela X-1 with MAXI
• Solution to the hyperon puzzle using dark matter
• Self-bound models of compact stars and recent mass-radius measurements
• Compact star in $f(T)$ gravity with Tolman-Kuchowicz metric potential
• The eccentric short-period orbit of the supergiant fast X-ray transient HD 74194 (=LM Vel)
• Stable Charged Gravastar model in Cylindrically Symmetric Space-time
• High-resolution X-ray spectroscopy of the stellar wind in Vela X-1 during a flare
• Neutron Star in Covariant $f(Q)$ gravity
• Analytical model of dark energy stars
• Model of hybrid star with baryonic and strange quark matter in Tolman-Kuchowicz spacetime
• Formation and Evolution of Galactic Intermediate/Low-Mass X-ray Binaries
• Anisotropic Durgapal-Fuloria Neutron Stars in $f(\mathcal{R},{\mathrm{T}}^2)$ Gravity
• Isotropic Buchdahl's relativistic fluid sphere within $f(R,T)$ gravity
• The Stability of Anisotropic Compact Stars Influenced by Dark Matter under Teleparallel Gravity: An Extended Gravitational Deformation Approach
• Evidence for an Evolving Cyclotron Line Energy in 4U 1538-522
• On the possibility of disk-fed formation in supergiant high-mass X-ray binaries
• Spectral evidence of an accretion disk in wind-fed X-ray pulsar Vela X-1 during an unusual spin-up period
• Charged Analogues of Isotropic Compact Stars Model with Buchdahl Metric in General Relativity
• Study of Viable Compact Stellar Structures in Non-Riemannian Geometry
• Probing the Cyclotron line characteristics of 4U 1538-522 using AstroSat-LAXPC
• Tidal effects on the radial velocity curve of HD77581 (Vela X-1)
• The maximum accreted mass of recycled pulsars
• Observing the onset of the accretion wake in Vela X-1
• Monitoring the Superorbital Period Variation and the Spin Period Evolution of SMC X-1
• Discovery of a 168.8 s X-ray pulsar transiting in front of its Be companion star in the Large Magellanic Cloud
• Probing large-scale wind structures in Vela X-1 using off-states with INTEGRAL
• Fluid sphere: stability problem and dimensional constraint
• Quadratic Rastall Gravity: from low-mass HESS J1731-347 to high-mass PSR J0952-0607 pulsars
• Long-duration Gamma-ray Burst Progenitors and Magnetar Formation
• Mass Distribution and Maximum Mass of Neutron Stars: Effects of Orbital Inclination Angle
• Populations of evolved massive binary stars in the Small Magellanic Cloud I: Predictions from detailed evolution models
• Anisotropic relativistic fluid spheres with a linear equation of state
• The Soft X-ray Spectrum of the High Mass X-Ray Binary V0332+53 in Quiescence
• Strange star with Krori-Barua potential in presence of anisotropy
• Ionized Reflection Spectra from Accretion Disks Illuminated by X-ray Pulsars
• Long-lived neutron-star remnants from asymmetric binary neutron star mergers: element formation, kilonova signals and gravitational waves
• Detection of nearly periodic spin period reversals in Vela X-1 on long time-scales: inkling of solar-like cycle in the donor star?
• Quantifying the evidence against a mass gap between black holes and neutron stars
• Is there a nearby microlensing stellar remnant hiding in Gaia DR3 astrometry?
• New Constraints on the Geometry and Kinematics of Matter Surrounding the Accretion Flow in X-ray Binaries from $Chandra$ HETG X-ray Spectroscopy
• Observables of spheroidal magnetized Strange Stars
• Neutron star mass in dark matter clumps
• Isotropic and anisotropic neutron star structure in 4D Einstein Gauss Bonnet Gravity
• Role of Curvature-Matter Coupling on Anisotropic Strange Stars
• Charged anisotropic compact objects obeying Karmarkar condition
• Variations of cyclotron resonant scattering features in Vela X-1 revealed with Insight-HXMT
• Superorbital Modulation in the High-Mass X-ray Binary 4U 1538-52, and Possible Modulation in IGR J16393-4643
• Modeling and Analyzing Stability of Hybrid Stars within $f(Q)$ Gravity
• Relativistic compact stars in Tolman spacetime via an anisotropic approach
• Gravitational collapse for a radiating anisotropic fluid
• Orbital phase resolved spectroscopy of 4U1538-52 with MAXI
• High-accuracy high-mass ratio simulations for binary neutron stars and their comparison to existing waveform models
• A detailed study of the modulation of the optical light from Sk160/SMC X-1
• Horndeski fermion-boson stars
• The K-corrections to radial velocity curves of optical components in X-Ray Binaries. HMXB with weak X-ray heating
• Torque reversal and cyclotron absorption feature in HMXB 4U 1538-522
• The structure of cold neutron star with a quark core within the MIT and NJL models
• Spectral analysis of the quiescent low-mass X-ray binary in the globular cluster M30
• Discovery of two eclipsing X-ray binaries in M51
• Long-term evolution of Cyclotron Line energy in an eclipsing pulsar 4U 1538-522
• Fluid pulsation modes from strange stars in a higher-dimensional space-time
• Impact of Non-metricity and Matter Source on the Geometry of Anisotropic Spheres
• Hybrid star within $f(\mathcal{G})$ gravity
• The masses of neutron stars
• Generating exact polytropes in non-conservative unimodular geometries
• Celestial attributes of Hybrid star in $5\mathcal{D}$ Einstein-Gauss-Bonnet gravity
• A New Measurement of the Spin and Orbital Parameters of the High Mass X-ray Binary Centaurus X-3 using AstroSat
• Exploring the viability of charged Spheres admitting non-metricity and matter source
• Well behaved class of Heintzmann's solution within $f(R,T)$ framework
• Direct nonparametric multimessenger constraints on the equation of state of cold dense nuclear matter
• Analytical Stellar Models of Neutron Stars in Teleparallel Gravity
• Neutron star calculations with the phenomenological three-nucleon force
• Triggering Electron Capture Supernovae: Dark Matter Effects in Degenerate White-Dwarf-like Cores of Super-Asymptotic Giant Branch Stars
• Cen x-3 as seen by MAXI during six years
• New Field OB and OBe Binaries of the SMC Wing: Observational Properties and Population Modeling
• On the Formation of SMC X-1: the Effect of Mass and Orbital Angular Momentum Loss
• The close environment of high-mass X-ray binaries at high angular resolution I. VLTI/AMBER and VLTI/PIONIER near-infrared interferometric observations of Vela X-1
• Non-singular T-K axion stars with/without the dynamical bosonic field in the presence of negative $\Lambda$ term
• Strange quark star in dilaton gravity
• Mass-Radius Constraints for 2S 0918-549 from an RXTE Superexpansion Burst: A Direct Cooling-Tail Analysis
• Astrometric microlensing probes of the isolated neutron star population with Roman
• Timing and spectral studies of the Be/X-ray binary EXO 2030+375 using Insight-HXMT observations
• On Modeling Anisotropic Quark Stars: The Role of Anisotropy in Radial Oscillation Spectra