If galaxies had the cosmological baryon-to-dark matter ratio, they would have3-30 times their observed baryon mass. These missing baryons are undetected, butsome fraction may surround a galaxy with a hot diffuse halo extending toR_virial (250 kpc). A loosely bound gaseous halo could be stripped in a clusteror group environment, but should be relatively undisturbed around isolatedlate-type spirals. Existing observations of spirals are mainly of nearbysystems, where only the inner parts fit in a field of view so a halo on thescale of R_virial would pass unnoticed. To detect or place limits on a largehalo of missing baryons, we propose to observe isolated L* spirals sufficientlydistant that we can detect emission to at least R_virial.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2010-12-04T05:58:44Z/2010-12-05T00:00:30Z
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 Joel Bregman, 2011, 'Large Halos of Missing Baryons Around Galaxies', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-4w0xeg4
