9 research outputs found
Timing of accreting neutron stars with future X-ray instruments: towards new constraints on dense matter equation of state
The Enhanced X-ray Timing and Polarimetry (eXTP) mission is a space mission
to be launched in the late 2020s that is currently in development led by China
in international collaboration with European partners. Here we provide a
progress report on the Czech contribution to the eXTP science. We report on our
simulation results performed in Opava (Institute of Physics of the Silesian
University in Opava) and Prague (Astronomical Institute of the Czech Academy of
Sciences), where the advanced timing capabilities of the satellite have been
assessed for bright X-ray binaries that contain an accreting neutron star (NS)
and exhibit the quasi-periodic oscillations.
Measurements of X-ray variability originating in oscillations of fluid in the
innermost parts of the accretion region determined by general relativity, such
as the radial or Lense-Thirring precession, can serve for sensitive tests
enabling us to distinguish between the signatures of different viable dense
matter equations of state. We have developed formulae describing non-geodesic
oscillations of accreted fluid and their simplified practical forms that allow
for an expeditious application of the universal relations determining the NS
properties. These relations, along with our software tools for studying the
propagation of light in strong gravity and neutron star models, can be used for
precise modeling of the X-ray variability while focusing on properties of the
intended Large Area Detector (LAD).
We update the status of our program and set up an electronic repository that
will provide simulation results and gradual updates as the mission
specifications progress toward their final formulation.Comment: 16 pages, 6 figures, proceedings of IBWS conference, eds. Martin
Jelinek and Marianna Dafcikova, 22-26 May 2023 (Karlovy Vary, Czech
Republic), ISSN: 1336-033