Temperature Profiles of Accretion Disks around Rapidly Rotating Neutron Stars in General Relativity and Implications for Cygnus X-2

Abstract

We calculate the temperature profiles of (thin) accretion disks around rapidly rotating neutron stars (with low surface magnetic fields), taking into account the full effects of general relativity. We then consider a model for the spectrum of the X-ray emission from the disk, parameterized by the mass accretion rate, the color temperature and the rotation rate of the neutron star. We derive constraints on these parameters for the X-ray source Cygnus X-2 using the estimates of the maximum temperature in the disk along with the disk and boundary layer luminosities, using the spectrum inferred from the EXOSAT data. Our calculations suggest that the neutron star in Cygnus X-2 rotates close to the centrifugal mass-shed limit. Possible constraints on the neutron star equation of state are also discussed.

18 pages, 9 figs., 2 tables, uses psbox.tex and emulateapj5.sty. Submitted to ApJ

References in corpus (5)

• Correlations between kHz QPO and Low Frequency Features Attributed to Radial Oscillations and Diffusive Propagation in the Viscous Boundary Layer Around a Neutron Star
• Kilohertz QPOs in Neutron Star Binaries modeled as Keplerian Oscillations in a Rotating Frame of Reference
• The radial effective temperature distribution of steady-state, mass-losing accretion disks
• Timing Spectroscopy of Quasi-Periodic Oscillations in the Low-Mass X-ray Neutron Star Binaries
• Interpretation of 35 Hz QPO in the Atoll Source 4U 1702-42 as a Low Branch of the Keplerian Oscillations Under the Influence of the Coriolis Force

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