Bright and absorbed galactic X-ray sources are surrounded by haloes of radiationscattered on interstellar dust grains. It is proposed to study the physical andchemical properties of these grains, in particular whether or not grains havesilicate cores surrounded by organic mantles. The refractive index of both andtherefore the scattering cross sections are substantially different. Therfore,the shape of a spectrally resolved halo could be dominated either by onecomponent or the other. Cyg X-2 and GX 339-4 have been selected because theyhave bright haloes but are not too absorbed in order to get sufficient intensityeven at lower energies. Another observation of GX 339-4 in timing mode (Wilms etal.) is devoted to the properties of the central source only.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2002-06-03T08:14:01Z/2004-02-18T11:28:42Z
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 Bernd Aschenbach, 2005, 'Spectro-Imaging of Dust Scattering Haloes', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-k6kqw74
