Relativistic iron emission lines in neutron star low-mass X-ray binaries as probes of neutron star radii

Abstract

Using Suzaku observations of three neutron star low-mass X-ray binaries (Ser X-1, 4U 1820-30 and GX 349+2) we have found broad, asymmetric, relativistic Fe K emission lines in all three objects. These Fe K lines can be well fit by a model for lines from a relativistic accretion disk ('diskline'), allowing a measurement of the inner radius of the accretion disk, and hence an upper limit on the neutron star radius. These upper limits correspond to 14.5 - 16.5 km for a 1.4 M(solar) neutron star. The inner disk radii we measure with Fe K lines are in good agreement with the inner disk radii implied by kHz QPOs observed in both 4U 1820-30 and GX 349+2, supporting the inner disk nature of kHz QPOs. Additionally, the Fe K lines observed in these neutron stars are narrower than those in the black holes that are thought to be close to maximally spinning, as one would expect if inferences for spin are robust.

arXiv comment6 pages, 3 figures, 3 tables, accepted to ApJ

References in corpus (41)

• The equation of state for nucleon matter and neutron star structure
• Neutron Star Structure and the Equation of State
• Neutron Star Observations: Prognosis for Equation of State Constraints
• Neutron Star Structure and the Neutron Radius of 208Pb
• ASCA observations of Seyfert 1 galaxies: II. Relativistic Iron K-alpha emission
• An X-ray spectral study of 24 type-1 AGN
• Constraining Black Hole Spin Via X-ray Spectroscopy
• Sonic-Point Model of Kilohertz Quasi-Periodic Brightness Oscillations in Low-Mass X-ray Binaries
• Correlations in the QPO Frequencies of Low Mass X-Ray Binaries and the Relativistic Precession Model
• Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes
• Gravitationally redshifted absorption lines in the X-ray burst spectra of a neutron star
• Constraints on the high-density nuclear equation of state from the phenomenology of compact stars and heavy-ion collisions
• Optical Observations of GRO J1655-40 in Quiescence I: A Precise Mass for the Black Hole Primary
• A Hydrogen Atmosphere Spectral Model Applied to the Neutron Star X7 in the Globular Cluster 47 Tucanae
• A Remarkable Three Hour Thermonuclear Burst From 4U 1820-30
• Optical and Infrared Photometry of the Micro-Quasar GRO J1655-40 in Quiescence
• Detection with RHESSI of high frequency X-ray oscillations in the tail of the 2004 hyperflare from SGR 1806-20
• Evaluating Spectral Models and the X-ray States of Neutron-Star X-ray Transients
• Suzaku observations of the hard X-ray variability of MCG-6-30-15: the effects of strong gravity around a Kerr black hole
• Magnetic Hydrogen Atmosphere Models and the Neutron Star RX J1856.5-3754
• Evidence for Black Hole Spin in GX 339-4: XMM-Newton EPIC-pn and RXTE Spectroscopy of the Very High State
• Correlation Between Energy Spectral States and Fast Time Variability and Further Evidence for the Marginally Stable Orbit in 4U 1820-30
• Evidence for a 2:3 resonance in Sco X-1 kHz QPOs
• Relations Between Timing Features and Colors in the X-Ray Binary 4U 0614+09
• Cooling of the quasi-persistent neutron star X-ray transients KS 1731-260 and MXB 1659-29
• Constraints on Neutron Star Properties from X-ray Observations of Millisecond Pulsars
• The Evolution of the Accretion Disk around 4U 1820-30 During a Superburst
• Evidence of a Broad Relativistic Iron Line from the Neutron Star Low-Mass X-ray Binary Serpens X-1
• Constraints on Neutron Star Parameters from Burst Oscillation Light Curves of the Accreting Millisecond Pulsar XTE J1814-338
• Changing Frequency Separation of Kilohertz Quasi-Periodic Oscillations in the Sonic-Point Beat-Frequency Model
• On the maximum amplitude and coherence of the kilohertz quasi-periodic oscillations in low-mass X-ray binaries
• Time-Resolved Ultraviolet Observations of the Globular Cluster X-ray Source in NGC 6624: The Shortest Known Period Binary System
• Simultaneous BeppoSAX and RXTE observations of the X-ray burst sources GX 3+1 and Ser X-1
• RXTE Studies of Long-Term X-ray Spectral Variations in 4U 1820-30
• A broad iron line in the Chandra/HETG spectrum of 4U 1705-44
• Discovery of Two Simultaneous Kilohertz QPOs in the Persistent Flux of GX 349+2
• On the inability of Comptonization to produce the broad X-ray iron lines observed in Seyfert nuclei
• Photometry of GX 349+2: Evidence for a 22-hour Period
• Non-Detection of Gravitationally Redshifted Absorption Lines in the X-ray Burst Spectra of GS 1826-24
• Effects of Resonance in Quasiperiodic Oscillators of Neutron Star Binaries
• On the X-ray fast-time variability of Sco X-2 (GX 349+2)

Cited by in corpus (113)

• A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation
• X-ray reflected spectra from accretion disk models. I. Constant density atmospheres
• The Mass and Radius of the Neutron Star in 4U 1820-30
• Broad emission lines for negatively spinning black holes
• Stellar-mass Black Hole Spin Constraints from Disk Reflection and Continuum Modeling
• The Masses and Spins of Neutron Stars and Stellar-Mass Black Holes
• Relativistic Lines and Reflection from the Inner Accretion Disks Around Neutron Stars
• Black hole accretion disks in the canonical low-hard state
• Broad relativistic iron emission line observed in SAX J1808.4-3658
• Dense matter with eXTP
• Surface Emission from Neutron Stars and Implications for the Physics of their Interiors
• A Chandra survey of fluorescence Fe lines in X-ray Binaries at high resolution
• XMM-Newton detects a relativistically broadened iron line in the spectrum of the ms X-ray pulsar SAX J1808.4-3658
• A new deterministic model of strange stars
• A systematic analysis of the broad Fe Kalpha line in neutron star LMXBs with XMM-Newton
• Constraints on the Neutron Star and Inner Accretion Flow in Serpens X-1 Using NuSTAR
• XMM-Newton observation of 4U 1820-30: Broad band spectrum and the contribution of the cold interstellar medium
• A relativistically smeared spectrum in the neutron star X-ray Binary 4U 1705-44: Looking at the inner accretion disc with X-ray spectroscopy
• Understanding Reverberation Lags in 1H0707-495
• Quiescent X-ray emission from Cen X-4: a variable thermal component
• A Hard Look at the Neutron Stars and Accretion Disks in 4U 1636-53, GX 17+2, and 4U 1705-44 with $\text{NuSTAR}$
• Measurement of neutron star parameters: a review of methods for low-mass X-ray binaries
• Detection of Reflection Features in the Neutron Star Low-Mass X-ray Binary Serpens X-1 with NICER
• Relativistic X-ray Reflection Models for Accreting Neutron Stars
• On Relativistic Disk Spectroscopy in Compact Objects with X-ray CCD Cameras
• Relativistic Iron Line Emission from the Neutron Star Low-mass X-ray Binary 4U 1636-536
• NuSTAR Observations of the Accreting Atolls GX 3+1, 4U 1702-429, 4U 0614+091, and 4U 1746-371
• A new radio census of neutron star X-ray binaries
• A self-consistent approach to the hard and soft states of 4U 1705-44
• Multi-state observations of the Galactic Black Hole XTE J1752-223: Evidence for an intermediate black hole spin
• Disk reflection signatures in the spectrum of the bright Z-source GX 340+0
• Suzaku broad-band spectrum of 4U 1705-44: Probing the Reflection component in the hard state
• Nuclear structure in strong magnetic fields: nuclei in the crust of a magnetar
• On Neutral Absorption and Spectral Evolution in X-ray Binaries
• Suzaku Observation of the Black Hole Candidate MAXI J1836-194 in a Hard/Intermediate Spectral State
• Radius Constraints from Reflection Modeling of Cygnus X-2 with NuSTAR and NICER
• X-ray reflection in a sample of X-ray bright Ultraluminous X-ray sources
• Super-Eddington accretion onto the Galactic ultraluminous X-ray pulsar Swift J0243.6+6124
• Photoionization modeling of oxygen K absorption in the interstellar medium:the Chandra grating spectra of XTE J1817-330
• A search for iron emission lines in the Chandra X-ray spectra of neutron star low-mass X-ray binaries
• A ionized reflecting skin above the accretion disk of GX 349+2
• Suzaku and BeppoSAX X-ray Spectra of the Persistently Accreting Neutron-Star Binary 4U 1705-44
• NuSTAR and XMM-Newton Observations of the Neutron Star X-ray Binary 1RXS J180408.9-34205
• Signatures of photon-axion conversion in the thermal spectra and polarization of neutron stars
• Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1
• Characterizing the Evolving X-Ray Spectral Features During a Superburst from 4U 1636-536
• Broad iron line in the fast spinning neutron-star system 4U 1636-53
• Evidence of Light-Bending Effects and its implication for spectral state transitions
• First detection of X-ray polarization from the accreting neutron star 4U 1820-303
• Nuclear Masses and Neutron Stars
• Variations in the dip properties of the low-mass X-ray binary XB 1254-69 observed with XMM-Newton and INTEGRAL
• Truncation of the Accretion Disk at One Third of the Eddington Limit in the Neutron Star Low-Mass X-ray Binary Aquila X-1
• A relativistic iron emission line from the neutron star low-mass X-ray binary GX 3+1
• On the Non-relativistic Origin of Red-skewed Iron Lines in CV, Neutron Star and Black Hole Sources
• X-ray Spectroscopy of MXB 1728-34 with XMM-Newton
• A NuSTAR observation of the low mass X-ray binary GX 349+2 throughout the Z-track
• Absence of reflection features in NuSTAR spectra of the luminous neutron star X-ray binary GX 5-1
• An Ultra-Fast X-ray Disk Wind in the Neutron Star Binary GX 340+0
• Relativistically broadened iron line in the SUZAKU observation of the neutron star X-ray binary 4U 1705-44
• A test of the nature of the Fe K Line in the neutron star low-mass X-ray binary Serpens X-1
• Discovery of Red-Skewed K_alpha iron line in Cyg X-2 with Suzaku
• A re-analysis of the NuSTAR and XMM-Newton broad-band spectrum of Ser~X-1
• Suzaku View of the Neutron Star in the Dipping Source 4U 1822$-$37
• GW170817 and GW190425 as Hybrid Stars of Dark and Nuclear Matters
• Iron-line and continuum variations in the XMM-Newton and Suzaku spectra of the neutron-star low-mass X-ray binary 4U 1636-53
• The reflection spectrum of the low-mass X-ray binary 4U 1636-53
• Simultaneous NICER and NuSTAR Observations of the Ultra-compact X-ray Binary 4U 1543-624
• On the disc reflection spectroscopy of NS LMXB Serpens~X-1: analysis of a recent NuSTAR observation
• Study of the X-ray properties of the neutron-star binary 4U 1728$-$34 from the soft to hard state
• Relativistic Disk Reflection in the Neutron Star X-ray Binary XTE J1709-267 with NuSTAR
• Analytical model of strange star in the low-mass X-ray binary 4U 1820-30
• Ways to constrain neutron star equation of state models using relativistic disc lines
• High-frequency variability in neutron-star low-mass X-ray binaries
• Are the kHz QPO lags in neutron star 4U 1608-52 due to reverberation?
• X-ray spectro-polarimetric characterization of GX 340+0 in the horizontal branch: a highly inclined source?
• Broad iron lines in neutrons stars: dynamical broadening or wind scattering?
• A strongly changing accretion morphology during the outburst decay of the neutron star X-ray binary 4U 1608-52
• The Equation of State of Neutron-Rich Matter at Fourth Order of Chiral Effective Field Theory and the Radius of a Medium-Mass Neutron Star
• The broadband spectral analysis of 4U 1702-429 using XMM-Newton and BeppoSAX data
• Study of the reflection spectrum of the bright atoll source GX 3+1 with NuSTAR
• Constraining distance and inclination angle of V4641 Sgr using $SWIFT$ and $NuSTAR$ observations during low soft spectral state
• Broad iron emission line and kilohertz quasi-periodic oscillations in the neutron star system 4U 1636-53
• Broadband X-ray emission and the reality of the broad iron line from the Neutron Star - White Dwarf X-ray binary 4U 1820-30
• Fluorescent Fe K line emission of gamma Cas stars I. Do gamma Cas stars host propelling neutron stars?
• Eclipses of jets and discs of X-ray binaries as a powerful tool for understanding jet physics and binary parameters
• Evidence of disc reflection in the X-ray spectrum of the neutron star low mass X-ray binary 4U 1636-536
• Iron Line from Neutron Star Accretion Disks in Scalar Tensor Theories
• AstroSat and NuSTAR observations of XTE J1739-285 during the 2019-2020 outburst
• The hard X-ray emission along the "Z" track in GX 17+2
• The cross-correlation analysis in Z source GX 349+2
• Understanding the Inner Structure of Accretion disk in GX 17+2: AstroSat's Outlook
• X-ray polarization of Z-type neutron star low-mass X-ray binaries -- I. Model-independent, time-resolved X-ray polarimetry
• Probing the accretion geometry of the atoll source 4U 1702-429 in different spectral states with NICER, NuSTAR, and AstroSat
• Broadband spectro-temporal investigation of neutron star low-mass X-ray binary GX 349+2
• Red-skewed K$\alpha$ iron lines in GX 13+1
• Probing the origin of the iron K_alpha line around stellar and supermassive black holes using X-ray polarimetry
• Frequency Resolved Spectroscopy of XB 1323-619 Using XMM-Newton data: Detection of a Reflection Region in the Disk
• Accretion tori around rotating neutron stars I: Structure, shape and size
• X-ray spectropolarimetric characterization of the Z-source GX 340+0 in the normal branch
• Reflecting on naked singularities: iron line fitting as a probe of the cosmic censorship conjecture
• Probing thermonuclear bursts and X-ray reflection features in Aql X-1 during 2024 outburst
• BeppoSAX and XMM-Newton spectral study of 4U 1735-44
• Modeling the upper kHz QPOs of 4U 1728-34 with X-ray reverberation
• Probing General Relativity with Accreting Black Holes
• X-ray view of emission lines in optical spectra: Spectral analysis of the two low-mass X-ray binary systems Swift J1357.2-0933 and MAXI J1305-704
• Relativistic disc line: a tool to constrain neutron star equation of state models
• Modeling reflection spectra of super-Eddington X-ray sources
• Iron Line Tomography of General Relativistic Hydrodynamic Accretion around Kerr Black Holes
• Black Holes at Work
• Search For Gravitational Redshifted Absorption Lines In LMXB Serpens X-1
• X-ray views of neutron star low-mass X-ray binaries
• The complex spectral behavior of the newly discovered neutron star X-ray binary Swift J1858.6-0814
• Probing the Black Hole Engine with Measurements of the Relativistic X-ray Reflection Component