This tag is associated with 8 posts

Gamma-rays from the Galactic Center, a dark matter

For a few years now, excess emission of gamma-rays in the direction of the Galactic Center has puzzled scientists. In the paper we discuss today, the authors re-analyze data from the Fermi telescope to get new insights into the origin of this excess emission. They make the case for the signal being described by dark matter particles annihilating in the center of our Galaxy.

An Unexpected Guest: Fermi-LAT Sees More Novae in Gamma Rays

In 2010 the Fermi-LAT reported a surprising discovery: detection of a gamma ray transient that appeared to come from a nova, V407 Cyg. Since V407 Cyg is a special type of nova, however, it was considered a one-off event. Now two other classical novae have also been found in gamma rays.

Is the Moon polluting your gamma-ray data?

I’m going to go ahead and give away the punchline: the answer to this post’s title is, “If your source is within 8 degrees of the Moon, quite probably.” — at least according to this paper’s authors. Read on to find out why!

The first detected signature of dark matter annihilation?

A flurry of recent papers point to detection of a ~130 GeV gamma-ray emission line from near the Galactic center. If real, this could be the first detection of a signature of annihilating dark matter.

Via Lactea Dark Matter Halos

Signals from Dark Matter Satellites and Fermi-LAT

Dark matter is not so dark as the name might imply. Although it so far refuses to interact with normal matter via any force other than gravity, there are secondary signals that we can detect. When we turn our gamma-ray telescopes on regions like the Galactic Center that contain a high density of dark matter, we expect to see a dim, widespread gamma ray haze coming from seemingly empty space, with no baryonic matter source. This paper, due to be published by the Astrophysical Journal, discusses the search for this signature by the collection of satellites that surrounds the Milky Way, and uses the lack of a detection to set an upper limit on the cross-section of the WIMP particle.

A look back on Fermi in 2011

Conference proceedings from the 2011 Fermi Symposium highlight some of the major science applications of the gamma-ray space observatory.