The NuSTAR observatory recently detected a previously unidentified extreme(Lx,peak virgul 2e40 erg/s) ultraluminous X-ray source (ULX) in the outskirts ofCircinus: Circinus ULX5. The current data support a simple disc-corona model,reminiscent of that invoked for Galactic binaries, implying the presence of amassive (virgul90 Msun) black hole accreting around it.s Eddington limit. This is anexciting possibility, as the presence of such a black hole may pose a challengeto our current understanding of stellar evolution. We propose to test thisscenario by undertaking a short 40 ks XMM ToO observation of ULX5 in an extremelow flux state. Should this scenario be correct, the source should transition toa regular disc-dominated state, which can easily be identified by XMM.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2018-02-07T11:55:14Z/2018-02-08T00:36:54Z
Version
17.56_20190403_1200
Mission Description
The European Space Agencys (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESAs second cornerstone of the Horizon 2000 Science Programme. It carries 3 high throughput X-ray telescopes with an unprecedented effective area, and an optical monitor, the first flown on a X-ray observatory. The large collecting area and ability to make long uninterrupted exposures provide highly sensitive observations. Since Earths atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is being made available to the scientific community, applying for observational periods on a competitive basis.
European Space Agency, Dr Dominic Walton, 2019, 'Observing the Extreme ULX Circinus ULX5 in an Extreme Flux State', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-rqfs8mp
