A sub-sample of bright ULXs (Lxvirgul(1-5)e40 erg/s) shows peculiar powerlaw likespectra in the 0.3- 10 keV band, with no high energy turn-off and short-termvariability at the level of virgul10%. These sources might host Intermediate MassBlack Holes (IMBHs) in a hard state, although their apparently flat spectra maybe the effect of low counting statistics. However, hard states with low energyspectral cut-off can indicate the presence of super-Eddington accreting neutronstars or stellar mass BHs. Here we propose simultaneous, deep XMM-Newton andNuSTAR observations of three best candidates to find evidence either of IMBHs,accreting sub-Eddington and with hard powerlaw spectra and high short termvariability, or of the characteristic spectral shape of the super-Eddington accretion.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2019-06-16T18:19:55Z/2019-06-17T15:16:35Z
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, Mr Fabio Pintore, 2020, 'UNVEILING BLACK HOLES AND NEUTRON STARS IN ULXs', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-4ar2lfp
