Can we constrain the neutron-star equation of state from QPO observations?. (arXiv:1905.05616v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Maselli_A/0/1/0/all/0/1">Andrea Maselli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pappas_G/0/1/0/all/0/1">George Pappas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pani_P/0/1/0/all/0/1">Paolo Pani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gualtieri_L/0/1/0/all/0/1">Leonardo Gualtieri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Motta_S/0/1/0/all/0/1">Sara Motta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ferrari_V/0/1/0/all/0/1">Valeria Ferrari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stella_L/0/1/0/all/0/1">Luigi Stella</a>
Using an accurate general-relativistic solution for the external spacetime of
a spinning neutron star, we assess for the first time the consistency and
reliability of geodesic models of quasiperiodic oscillations~(QPOs), which are
observed in the X-ray flux emitted by accreting neutron stars. We analyze three
sources: 4U1608-52, 4U0614+09, and 4U1728-34. Our analysis shows that geodesic
models based on pairs of high-frequency QPOs, identified with the azimuthal and
periastron precession frequencies, provide consistent results. We discuss how
observations of QPO doublets can be used to constrain the equation of state of
neutron stars in a way complementary to other observations. A combined analysis
of the three sources favours neutron stars with mass above two solar masses and
relatively stiff equations of state.
Using an accurate general-relativistic solution for the external spacetime of
a spinning neutron star, we assess for the first time the consistency and
reliability of geodesic models of quasiperiodic oscillations~(QPOs), which are
observed in the X-ray flux emitted by accreting neutron stars. We analyze three
sources: 4U1608-52, 4U0614+09, and 4U1728-34. Our analysis shows that geodesic
models based on pairs of high-frequency QPOs, identified with the azimuthal and
periastron precession frequencies, provide consistent results. We discuss how
observations of QPO doublets can be used to constrain the equation of state of
neutron stars in a way complementary to other observations. A combined analysis
of the three sources favours neutron stars with mass above two solar masses and
relatively stiff equations of state.
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