American Physical Society | APS Physics Tip Sheet | 2016 Jan 02
[img3="Gamma ray picture of the Milky Way, as seen by the NASA Fermi satellite. Inserts: two independent statistical analyses showed that the distribution of photons is clumpy rather than smooth, indicating that the excess gamma rays from the centre of our galaxy are unlikely to be caused by dark matter annihilation.Two studies suggest that neutron stars -- and not dark matter -- could be responsible for an excess of gamma rays from the Milky Way's center.
(Image: Christoph Weniger, UvA, © UvA/Princeton)"]http://www.princeton.edu/main/images/ne ... e-1150.jpg[/img3][hr][/hr]
Recent observations have revealed an excess of gamma rays near the center of our galaxy. Intriguingly, this signal is consistent with the diffuse flux expected from the annihilation of dark matter particles. However, researchers have suggested that these gamma rays might instead come from conventional astrophysical sources, such as spinning neutron stars (pulsars) that emit beams of radiation. Their emission could appear diffuse simply because it cannot be resolved by the limited spatial resolution of existing telescopes. Now, the studies of two independent teams (one at the University of Amsterdam, one at Princeton and MIT) support the pulsar hypothesis. The groups modeled the gamma-ray emission near the galactic center, showing that a pulsar population could fully explain the signal.
Millisecond pulsars are likely to account for dark matter signal in galactic centre
University of Amsterdam | 2016 Feb 03
Galactic center's gamma rays unlikely to originate from dark matter, evidence shows
Princeton University | 2016 Feb 04
Strong support for the millisecond pulsar origin of the Galactic center GeV excess - Richard Bartels et al
- Physical Review Letters 116:051102 (04 Feb 2016) DOI: 10.1103/PhysRevLett.116.051102
arXiv.org > astro-ph > arXiv:1506.05104 > 16 Jun 2015 (v1), 01 Oct 2015 (v2)
- Physical Review Letters 116:051103 (04 Feb 2016) DOI: 10.1103/PhysRevLett.116.051103
arXiv.org > astro-ph > arXiv:1506.05124 > 16 Jun 2015 (v1), 03 Feb 2016 (v3)