We’re pleased to be able to provide a new set of Fermi surveys. Fermi is the highest energy survey in SkyView and heretofore we had been providing two bands of Fermi data, from 100 to 5450 MHz and 5450 MHz to 300 GeV. Fermi’s resolution is a very strong function of energy. With the bands we’d originally chosen, low energy, low resolution photons blurred the images of most sources. While the top band had very reasonable resolution, it had relatively few photons. The new Fermi data is broken into 5 bands:
- 30-100 MeV
- 100-300 MeV
- 300-1000 MeV
- 1-3 GeV
- 3-300 GeV
This seems to give a cleaner separation of the low energy/resolution data while keeping enough photons in the higher energy bands to really show the sky. This all sky image shows data from bands 3-5.
Harder gamma-ray sources show as blue. A myriad Galactic and high-latitude sources show.
We’ve imaginatively named these surveys Fermi 1, 2, 3, 4 and 5 in order of increasing energy. They contain all of the Fermi data available through the beginning of April 2012. The Fermi sky exposure is now considered to be sufficiently uniform that we are providing these surveys as counts maps rather than intensity maps. We’ll be adding exposure information soon.