We request three 70ks observations of the bright ULX Holmberg II X-1, separatedby 2-5 months. We also request two 120ks observations, separated by 2-6 months,of another bright ULX Holmberg IX X-1, thus making a total of 450ks exposure.The primary purpose of these observations is to measure the broad band noisepower density spectra (PDS) and X-ray spectral shapes at different flux levels.The existing long observations have provided PDS and X-ray spectra at singleepochs and suggest that both these ULXs are likely in the strongly Comptonizedvery high states. The proposed observations will allow us to define spectralstates of ULXs at different flux levels, and make a definitive analogy betweenspectral states of ULXs and the well studied Galactic black hole X-ray binaries (BHBs).
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2007-09-18T16:25:55Z/2007-09-19T13:19:31Z
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, Prof Richard Griffiths, 2008, 'Probing the spectral-temporal states of bright ULXs at different flux levels', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-ac5j5yp
