A new astro-ph paper cross-linked to hep-ph,
The approximate shape of Reticulum 2, a dwarf galaxy, and the light it emits.
If that deviation is a sign of new physics, and it is a huge "If" indeed, the interpretation is that the signal is due to a pairwise self-annihilating particle whose mass is a few times \(100\GeV\).
The signal-resembling observations have been made in Reticulum 2, a dwarf galaxy. One must realize that Reticulum 2 was "cherry-picked" as the "most signal-like dwarf galaxy" among a few dozens of dwarf galaxies which should reduce your faith (or certainty) that the signal is real.
An excess: in the middle of the picture, the red crosses seem to be above the solid black line.
Reticulum means a "small reticle" in Latin, and a "reticle" is a web, typically a system of thin lines (with a cross) in the circular visual field of a telescope. More importantly, Reticulum 2 (Ret2) is a dwarf galaxy which is really close – it is about 30 kpc away from Pilsen. ;-) It's further than Prague but it is very close – almost exactly equal to the diameter of the Milky Way (according to Wolfram Alpha). Ret2 is the third closest dwarf galaxy after Segue 1 (Seg1, 23 kpc) and Sagittarius (24 kpc).
Ret2 is one of the 9 new low-luminosity objects. It (or they) may be viewed as "satellites of the Milky Way". Among the 9 guys, it's probably the most obvious one. Along with Eridanus 2 and no one else, it shows a statistically significant elongation (others are round) which may perhaps increase the density at some points and improve the odds that self-annihilation of dark matter takes place there.
The signal-like optimistic interpretation is that a new particle, such as a superpartner, pairwise annihilates first into a pair of Standard Model \(X\bar X\) particles before they create some gamma-rays. We don't know what the \(X\bar X\) pair is. Depending on whether \(X\bar X\) is \(b\bar b\) or \(\tau^+\tau^-\) or \(hh\) or \(\mu^+\mu^-\), the mass \(m\) and \(J\langle\sigma v \rangle\) of the dark matter particle may have different values – the mass is distributed in rather wide intervals roughly between \(50\) and \(1,000\GeV\).
It's obviously incorrect to say that the dark matter has been discovered. After all, the significance level wouldn't be sufficient for a hard discovery even if one forgot about all the other possible reasons to question the bold claim suggested in this paper (Ret2 was cherry-picked; Fermi folks haven't noticed that; even according to these 7 authors, it may be due to astrophysical sources, etc.). Nevertheless, the evidence has some beef and it's plausible that the signal is real and in the future, with the hindsight, these folks will be quoted as those who already saw the actual proof of the dark matter.
Thanks to Matt Buckley