Notes to self

Don’t jump to conclusions, read only papers > 15 pages and stop reading the news (what can I say, I’m addicted). Coincidence/correlation doesn’t necessarily imply there’s a link there/causation, statistics students can tell you that. False cause. Media gives things a nice polish – http://phys.org/news/2015-03-gamma-rays-newly-dwarf-galaxy.html, stopping just short of saying we’ve done got it. Or so it seems to me. In other words, there’s a new paper http://arxiv.org/abs/1503.02320 coming from Cambridge, Carnegie Mellon and Brown U’s that identifies gamma ray emissions from a dwarf galaxy called Reticulum 2. In case you’re wondering, gamma rays could be used to track down dark matter, IF we assume a few things:

– dark matter is the kind predicted by supersymmetry, as in wimps (weakly interacting massive particles).

– dark matter annihilation produces gamma ray bursts.

– interference and contamination (other likely sources of gamma rays, like pulsars, quasars or black holes emitting Hawking radiation and so on) can be ruled out.

The paper is nicely done, though short. Spectrum goes up between 2 and 10 GeV. There are a few assumptions I can’t agree on, though – the title (of the paper) is a wee bit misleading considering the main work (title being “Evidence for Gamma-ray emission from newly discovered dwarf galaxy Reticulum 2” which says nothing of dark matter), also interference hasn’t been ruled out and source contamination is unlikely for energies above 1 GeV if we consider the known sources of gamma rays. A few calculations show likeness to the dark matter scenario.

So, we got something. Gamma ray emissions. What’s the biggest assumption here? That this gamma ray production is due to wimp annihilations when dark matter halo mass is unknown. So I got all worked up. Ayah! Hopefully we’ll get to see an estimate then, to verify the calculated dark matter content.

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