Absorption in the OVII (21.60 A) line at zero redshift shows the presence of hotgas. Our recent study, using 26 absorption sightlines, shows that thisabsorption is probably from a halo around the Milky Way rather than a LocalGroup medium. However, the size of the hot halo is poorly known (15-110 kpc)because there are no useful existing absorption sightlines across the Galacticbulge, which provide the strongest constraints. We propose a lengthy observationof the brightest known AGN in the direction of the Galactic bulge, whereexisting data indicate an absorption line of above average strength. Theresulting equivalent width measurement will strongly constrain the size and massof the hot halo.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2007-10-09T23:46:20Z/2007-10-31T00:47:44Z
Version
PPS_NOT_AVAILABLE
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 Joel Bregman, 2008, 'The Mass and Size of the Hot Galactic Halo', PPS_NOT_AVAILABLE, European Space Agency, https://doi.org/10.5270/esa-82l1yfz
