Determination of the mass of the neutron star in SMC X-1, LMC X-4 and Cen X-3 with VLT/UVES

Abstract

We present the results of a spectroscopic monitoring campaign of the OB-star companions to the eclipsing X-ray pulsars SMC X-1, LMC X-4 and Cen X-3. High-resolution optical spectra obtained with UVES on the ESO Very Large Telescope are used to determine the radial-velocity orbit of the OB (super)giants with high precision. The excellent quality of the spectra provides the opportunity to measure the radial-velocity curve based on individual lines, and to study the effect of possible distortions of the line profiles due to e.g. X-ray heating on the derived radial-velocity amplitude. Several spectral lines show intrinsic variations with orbital phase. The magnitude of these variations depends on line strength, and thus provides a criterion to select lines that do not suffer from distortions. The undistorted lines show a larger radial-velocity amplitude than the distorted lines, consistent with model predictions. Application of our line-selection criteria results in a mean radial-velocity amplitude K(Opt) of 20.2 +/- 1.1, 35.1 +/- 1.5, and 27.5 +/- 2.3 km/s (1 sigma errors), for the OB companion to SMC X-1, LMC X-4 and Cen X-3, respectively. Adding information on the projected rotational velocity of the OB companion (derived from our spectra), the duration of X-ray eclipse and orbital parameters of the X-ray pulsar (obtained from literature), we arrive at a neutron star mass of 1.06^{+0.11}_{-0.10}, 1.25^{+0.11}_{-0.10} and 1.34^{+0.16}_{-0.14} M{sun} for SMC X-1, LMC X-4 and Cen X-3, respectively. The mass of SMC X-1 is near the minimum mass (~1 M{sun}) expected for a neutron star produced in a supernova. We discuss the implications of the measured mass distribution on the neutron-star formation mechanism, in relation to the evolutionary history of the massive binaries.

arXiv commentAccepted for publication in Astronomy and Astrophysics

References in corpus (20)

• The Physics of Neutron Stars
• A statistical study of 233 pulsar proper motions
• Observations of Accreting Pulsars
• Neutron Star Mass Measurements. I. Radio Pulsars
• The Neutron Star and Black Hole Initial Mass Function
• Pulsar Recoil and Gravitational Radiation due to Asymmetrical Stellar Collapse and Explosion
• Pulsar Recoil by Large-Scale Anisotropies in Supernova Explosions
• A New Class of High-Mass X-ray Binaries: Implications for Core Collapse and Neutron-Star Recoil
• The mass of the neutron star in Vela X-1 and tidally induced non-radial oscillations in GP Vel
• The mass of the neutron star in Vela X-1
• Spectral analysis of early-type stars using a genetic algorithm based fitting method
• The Double Pulsar J0737--3039: Testing the Neutron Star Equation of State
• The Mass of a Millisecond Pulsar
• INTEGRAL insight into the inner parts of the Galaxy. High mass X-ray binaries
• Quasi-Periodic Occultation by a Precessing Accretion Disk and Other Variabilities of SMC X-1
• Long-term Properties of Accretion Disks in X-ray Binaries: I. the variable third period in SMC X-1
• XMM-Newton X-ray spectroscopy of the high-mass X-ray binary 4U1700-37 at low flux
• Orbital Decay in LMC X-4
• Equation of state of dense matter and the minimum mass of cold neutron stars
• Modeling the near-infrared lines of O-type stars

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