Abstract
The recently discovered accreting X-ray pulsar IGR J17480-2446 spins at a frequency of a??11Hz. 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.
Original language | English |
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Pages (from-to) | 1 - 5 |
Number of pages | 5 |
Journal | The Astrophysical Journal Letters |
Volume | 740 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2011 |