Combining more than 4 years of observations, the inner Galaxy has been mapped in the 511 keV positron annihilation line with unprecedented detail as shown above using the SPI spectrometer. For the first time, positron annihilation is found to be asymmetric in the inner Galactic disk. Consistent with earlier findings, the annihilation emission is brightest around the Galactic centre. In the sky maps, the Galactic centre is at the origin and the Galactic disk runs along the equator. (Credit: ESA/ INTEGRAL/ MPE (G. Weidenspointner et al.))From Space Daily:
ScienceDaily (Aug. 2, 2009) — A team of researchers working with data from ESA’s Integral gamma-ray observatory has disproved theories that some form of dark matter explains mysterious radiation in the Milky Way.
That this radiation exists has been known since the 1970s, and several theories have been proposed to explain it. Integral’s unprecedented spectral and spatial resolution showed that it strongly peaks towards the centre of the Galaxy, with an asymmetry along the Galactic disc.
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