APOD: Fermi Catalogs the Gamma ray Sky (2010 Mar 18)

[APOD Robot]

Fermi Catalogs the Gamma ray Sky

Explanation: What shines in the gamma-ray sky? The most complete answer yet to that question is offered by the Fermi Gamma-ray Space Telescope's first all-sky catalog. Fermi's sources of cosmic gamma-rays feature nature's most energetic particle accelerators, ultimately producing 100 MeV to 100 GeV photons, photons with more than 50 million to 50 billion times the energy of visible light. Distilled from 11 months of sky survey data using Fermi's Large Area Telescope (LAT), the 1,451 cataloged sources include energetic star burst galaxies and active galactic nuclei (AGN) far beyond the Milky Way. But within our own galaxy are many pulsars (PSR) and pulsar wind nebulae (PWN), supernova remnants (SNR), x-ray binary stars (HXB) and micro-quasars (MQO). Fermi's all sky map is shown centered on the Milky Way with the diffuse gamma-ray emission from the Galactic plane running horizontally through the frame. To locate the cataloged gamma-ray sources, just slide your cursor over the map. For now, 630 of the sources cataloged at gamma-ray energies remain otherwise unidentified, not associated with sources detected at lower energeries.

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[GLN]

Why does there appear to be a hole in the "mapped" view vs the unmapped view just to the right and slightly below what seems to be galactic center (or @ least image center), of an extremely bright source (in the unmapped view?)?

[GLN]

Whoops. My bad. It appears that my loss of the source was just due to the "crush" of the signal by a label. I guess it just goes to prove that how you look at something, is just as important as just looking @ it.

[HLR]

With the milky way being more prominent in the southern hemisphere, I wonder if all those gamma ray have a little to do with the ozone depletion. What about cancer rates in the southern hemisphere vs. the northern hemisphere?

[owlice]

I think APOD just might be responsible for 80% of my Googling...

From Wikipedia (because of course I had to look up blazar):

A blazar (blazing quasi-stellar object) is a very compact quasar (quasi-stellar object) associated with a presumed supermassive black hole at the center of an active, giant elliptical galaxy. Blazars are among the most violent phenomena in the universe and are an important topic in extragalactic astronomy.

Blazars are members of a larger group of active galaxies, also termed active galactic nuclei (AGN). A few rare objects may be "intermediate blazars" that appear to have a mixture of properties from both OVV quasars and BL Lac objects. The name "blazar" was originally coined in 1978 by astronomer Edward Spiegel to denote the combination of these two classes.

[biddie67]

When I read through the various links in today's APOD description and try to get an understanding of those many vast sources of such immense energy scattered through out the universe, it is easier to understand the forces that might have been behind the "Big Bang" when all those energy sources were possibly compressed into one tiny space and then released.

But the impossible question -- how could all that energy have been so compressed initially and what was there before it? It's hard to believe that we will ever really know ....