The detection of X-ray absorption and emission lines at z = 0 has beeninterpreted as an extensive isothermal Local Group medium with a gaseous massexceeding the baryonic mass of all Local Group galaxies. A large gaseous masshelps to solve the missing baryon problem , a leading cosmological issue.However, the gas mass is highly model dependent, and in an alternative model,the gas lies in a Galactic halo of size 50 kpc and with a gas mass orders ofmagnitude lower. We can discriminate between the Galactic Halo and Local Groupmodels by determining whether most of the diffuse X-ray emission (0.5-1 keV)lies in front or behind a Magellanic Stream cloud at a distance of 50 kpc. Forthe Local Group model, the MS cloud will absorb the emission beyond it, casting an X-ray shadow .
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2004-01-03T05:02:42Z/2004-01-03T19:27:52Z
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 JOEL BREGMAN, 2005, 'EMISSION FROM THE MISSING BARYONS IN THE LOCAL GROUP', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-p1h43r9
