What has caused the dimming of the neutron star ULX NGC 7793 P13?
Abstract
NGC 7793 P13 has been an ideal target to study super-Eddington accretionin ultra-luminous X-ray pulsars thanks to its strong pulsationsand high flux. However, in 2019 its X-ray flux started to decline,and the source entered an off-state. It quickly recovered from thatbut has been in a very low state since then. During the decline, thespin-up was continuing at almost the same rate as during the high state,indicating that accretion was continuing unabated. During the currentlow state the flux is too low to see pulsations and we do not know thecurrent spin-period evolution. We therefore ask for an XMM-Newton ToOobservation within a few weeks from when P13 emerges from the low state,in order to obtain another spin measurement and understand the natureof the off- and low state.
- Publication:
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XMM-Newton Proposal
- Pub Date:
- October 2021
- Bibcode:
- 2021xmm..prop...33F