Bibcode
Ponti, G.; Bianchi, S.; Muñoz-Darias, T.; Nandra, K.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society: Letters, Volume 481, Issue 1, p.L94-L99
Advertised on:
11
2018
Citations
13
Refereed citations
11
Description
The determination of fundamental parameters in low-mass X-ray binaries
(LMXBs) typically relies on measuring the radial velocity curve of the
companion star through optical or near-infrared spectroscopy. It was
recently suggested that high resolution X-ray spectroscopy might enable
a measurement of the radial velocity curve of the compact object by
monitoring the Doppler shifts induced by the orbital motion of the disc
wind or the disc atmosphere. We analysed a Chandra-HETG+NuSTAR soft
state observation of MXB 1659-298, an eclipsing neutron star LMXB. We
measured a radial velocity curve whose phase offset and semi-amplitude
are consistent with the primary star. We derived the value for the
semi-amplitude of the radial velocity for the compact object
K1 = 89 ± 19 km s-1, constrained the mass
of the secondary (0.3 M⊙ ≤ M2 ≤ 0.8
M⊙) and the orbital inclination of the binary system
(73°≤ i≤77°). These values are consistent with previous
estimates from independent methods. Via the same technique, the next
generation of X-ray observatories equipped with high spectral resolution
instruments (e.g. Athena) will have the potential to measure the radial
velocity curve of the primary in high inclination X-ray binaries to an
accuracy of a few per cent.
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Black holes, neutron stars, white dwarfs and their local environment
Accreting black-holes and neutron stars in X-ray binaries provide an ideal laboratory for exploring the physics of compact objects, yielding not only confirmation of the existence of stellar mass black holes via dynamical mass measurements, but also the best opportunity for probing high-gravity environments and the physics of accretion; the most
Montserrat
Armas Padilla