We propose to observe the Perseus cluster, in order to accurately constrain the spatial distribution of the Fe XXV n=3-1 to n=2-1 fluxes. The n=2-1 resonance line is known to be optically thick to scattering, the n=3-1 lines are not. The ratio map therefore provides a direct measure of the resonance scattering depth, which, when combined with the volume emission measure and the angular size of the cluster, produces an estimate of the absolute distance in a manner entirely analogous to the Sunyaev-Zeldovich effect. Together with the redshift, this gives the Hubble constant directly, just from spatially resolved X-ray spectroscopy.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2001-02-10T07:15:05Z/2001-02-10T19:16:02Z
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 Frits Paerels, 2002, 'An X-ray spectroscopic determination of the Hubble constant', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-3hychlr
