A Search for X-ray Reverberation in the Ultraluminous X-ray Source NGC 5408 X-1
Abstract
We propose simultaneous optical (VLT/FORS2) and X-ray (XMM-Newton) observations of the ultraluminous X-ray source (ULX) NGC 5408 X-1 (hereafter X-1) in order to search for the signatures of X-ray reprocessing in its accretion disk. Our proposed observations will enable the first sensitive search for X-ray - optical correlations in a ULX and will address key questions regarding the nature of the accretor in X-1. For example, detection of an X-ray -- optical correlation, a signature of reprocessing, will establish that the optical flux is largely produced in the accretion disk and not the companion star. Measurement of X-ray optical time lags can lead to a mass estimate via the techniques of reverberation mapping.
- Publication:
-
XMM-Newton Proposal
- Pub Date:
- October 2012
- Bibcode:
- 2012xmm..prop..107S
- Keywords:
-
- White Dwarf Binaries;
- Neutron Star Binaries;
- Cataclysmic Variables;
- ULXs;
- Black Holes;
- NGC 5408 X-1;
- NGC 5408 X-1