Understanding state transitions in ULXs: diagnostics through wind spectroscopy
Abstract
In recent work done with XMM-Newton, we have discovered that ultraluminousX-ray sources have strong relativistic winds in agreement with theoreticalpredictions of super-Eddington accretion. Such winds vary on timescalesof days and can become optically thick enough to block and reprocess thedisc X-ray photons, thus changing the spectral shape of the source into anultraluminous supersoft X-ray source. We propose to test this hypothesis,by studying a transitional object where the wind is so strong that it isalready causing significant absorption of the harder X-ray continuum:NGC 55 ULX. A 130ks XMM observation triggered during a high X-ray fluxstate will enable to perform time-/flux-resolved X-ray spectroscopy ofthe wind and probe the transition from supersoft to soft ULX.
- Publication:
-
XMM-Newton Proposal
- Pub Date:
- October 2019
- Bibcode:
- 2019xmm..prop..157P