A sub-sample of bright Ultraluminous X-ray Sources (L_Xvirgul(1-5)x10^40 erg/s) showspeculiar powerlaw like spectra, with no high energy turn-off and short-termvariability at the level of virgul10%. These sources might host Intermediate MassBlack Holes (IMBHs) in a low/hard state, although their apparently flat spectralshape may be the effect of poor counting statistics. Here we proposesimultaneous, deep XMM- Newton and NuSTAR observations of four such objects tofind evidence either of the X-ray properties (powerlaw spectra and short termvariability) that should characterize sub-Eddington accretion onto an IMBH or ofthe characteristic spectral curvature of the .Ultraluminous state.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2017-01-18T19:45:14Z/2017-01-19T09:38:34Z
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 Fabio Pintore, 2018, 'Searching for IMBH candidates among Ultraluminous X-ray Sources', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-5y6p2xl
