Bibcode
Cavecchi, Y.; Patruno, A.; Haskell, B.; Watts, A. L.; Levin, Y.; Linares, M.; Altamirano, D.; Wijnands, R.; van der Klis, M.
Bibliographical reference
The Astrophysical Journal Letters, Volume 740, Issue 1, article id. L8 (2011).
Advertised on:
10
2011
Citations
52
Refereed citations
46
Description
The recently discovered accreting X-ray pulsar IGR J17480-2446
spins at a frequency of ~11 Hz. We show that Type I X-ray bursts from
this source display oscillations at the same frequency as the stellar
spin. IGR J17480-2446 is the first secure case of a slowly
rotating neutron star (NS) which shows Type I burst oscillations (BOs),
all other sources featuring such oscillations spin at hundreds of Hertz.
This means that we can test BO models in a completely different regime.
We explore the origin of Type I BOs in IGR J17480-2446 and
conclude that they are not caused by global modes in the NS ocean. We
also show that the Coriolis force is not able to confine an
oscillation-producing hot spot on the stellar surface. The most likely
scenario is that the BOs are produced by a hot spot confined by
hydromagnetic stresses.