The hunt for dim matter turns to subhalos

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In further to training us about pulsars, immeasurable rays and supermassive black holes, a Fermi Gamma Ray Space Telescope is one of a world’s premier dim matter experiments. In many models, a interactions of dim matter particles can emanate enterprising photons, famous as gamma rays. Fermi provides us with a many supportive perspective of a gamma-ray sky and is means to exam many of a many earnest theories of dim matter.

A group of astrophysicists is looking for dim matter in a form of subhalos. These clumps of dim matter within a Milky Way are expected to furnish a particular gamma-ray signal. Image pleasantness of The Aquarius Project

A group of astrophysicists is looking for dim matter in a form of subhalos. These clumps of dim matter within a Milky Way are expected to furnish a particular gamma-ray signal. Image pleasantness of The Aquarius Project

Over a past several years, my collaborators and we have published a array of papers describing an additional of gamma rays from a segment surrounding a core of a Milky Way. After many prolonged discussions, arguments and debates, a infancy of a gamma-ray astrophysics village seems to have reached a accord that this additional is genuine and is in need of an explanation. One sparkling probability is that these gamma rays could be constructed by dim matter particles. But even nonetheless this vigilance looks really most like what we approaching from dim matter, we can’t wholly order out other explanations, such as a array of new outbursts of immeasurable rays or some opposite race of gloomy gamma-ray sources.

One approach to potentially endorse a dim matter start for this additional would be to observe a same spectrum of gamma rays from differently invisible clumps of dim matter — famous as subhalos — elsewhere in a sky. In fact, if a gamma rays from a Galactic Center do come from dim matter particles, we guess that Fermi should be means to detect a handful of these subhalos as splendid gamma-ray sources. The plea is that Fermi has rescued hundreds of bright, unclear sources, a immeasurable infancy of that are not associated to dim matter. This vast haystack of sources creates it tough to find a dim matter subhalos that are a needles we are looking for.

But in one critical respect, dim matter subhalos should demeanour opposite from other kinds of gamma-ray sources: They should be somewhat extended or “puffy.” My collaborators (Bridget Bertoni of a University of Washington and Tim Linden of a University of Chicago) and we have recently found justification that some of Fermi’s unclear sources are in fact extended, creation them seem some-more expected to be dim matter subhalos. We continue to investigate a data, and nonetheless we’re not prepared to explain find yet, we are really vehement that this new information competence make it probable to exclusively exam — and maybe even endorse — a dim matter start for Fermi’s Galactic Center gamma-ray excess.

Source: FNAL, created by Dan Hooper