Thursday, January 20, 2011

Fermi Bubbles

I went to Astronomy Night tonight and heard a good talk on Fermi Bubbles. A video will probably pop up in their archive soon.

Here's the press release from the discovery in November, Astronomers Find Giant, Previously Unseen Structure in our Galaxy. Doug Finkbeiner gave the talk. Basically they were using the Fermi space telescope to look at gamma rays across the sky in trying to understand dark matter. They took images of the whole sky and subtracted a model of known gamma ray sources and they were left with this:


He had a black and white image that was easier to see, but basically you're looking at the whole sky. the center of the galaxy is in the center and you see 180 degrees to either side and up/down. Notice the bright figure eight in the center, that's the discovery. Here's an artist's rendition by NASA


It turns out NASA always shades gamma rays as magenta and x-rays as blue. The picture shows the milky way galaxy edge on and picture us off to the right. The big pink blobs are the gamma rays and they're that big. We don't really know what made them but it's a good guess that it has something to do with the massive black hole at the center of the galaxy.

One obvious thing to do would be to look at other galaxies and see if we see these gamma-ray bubbles, but we're not very good at detecting gamma rays from other galaxies. We need more sensitive detectors for that.


Richard said...

I've seen that picture. I think that it is awesome that a feature that can only be seen in gamma rays would take up a large part of the night sky if my eye could detect it.

Think about when you have a dark enough sky to see the milky way go across, and then superimpose these huge gamma ray bubbles above and below it.

Howard said...

I think my favorite line from Battlestar (certainly of the last season) was Cavil saying "I don't want to be human! I want to see gamma rays! I want to hear X-rays! And I want to - I want to smell dark matter!"