Retrograde accretion discs in high-mass Be/X-ray binaries
Apr 20, 20174 pages
Published in:
- Mon.Not.Roy.Astron.Soc. 470 (2017) 1, L21-L24
- Published: Sep 1, 2017
e-Print:
- 1704.06364 [astro-ph.HE]
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Abstract: (Oxford University Press)
We have compiled a comprehensive library of all X-ray observations of Magellanic pulsars carried out by XMM–Newton, Chandra and RXTE in the period 1997–2014. In this work, we use the data from 53 high-mass Be/X-ray binaries in the Small Magellanic Cloud to demonstrate that the distribution of spin-period derivatives versus spin periods of spinning-down pulsars is not at all different from that of the accreting spinning-up pulsars. The inescapable conclusion is that the up and down samples were drawn from the same continuous parent population; therefore, Be/X-ray pulsars that are spinning down over periods spanning 18 yr are, in fact, accreting from retrograde discs. The presence of prograde and retrograde discs in roughly equal numbers supports a new evolutionary scenario for Be/X-ray pulsars in their spin period–period derivative diagram.Note:
- To appear in MNRAS Letters
- accretion, accretion discs
- stars: magnetic field
- stars: neutron
- X-rays: binaries
References(27)
Figures(3)