Major improvements to methods used to process observations from NASA's Fermi Gamma-ray Space Telescope have yielded an expanded, higher-quality set of data that allows astronomers to produce the most detailed census of the sky yet made at extreme energies.

By carefully reexamining every gamma-ray and particle detection by the Large Area Telescope (LAT) since Fermi's 2008 launch, scientists improved their knowledge of the detector's response to each event and to the background environment in which it was measured. This enabled the Fermi team to find many gamma rays that previously had been missed while simultaneously improving the LAT's ability to determine the directions of incoming gamma rays. The improved data, known as Pass 8, effectively sharpens the LAT's view while also significantly widening its useful energy range.

For the first time, Fermi data now extend to energies previously seen only by ground-based detectors. Because ground-based telescopes have much smaller fields of view than the LAT, which scans the whole sky every three hours, they have detected only about a quarter of the objects in the new catalog.

A long time ago in a galaxy half the universe away, a flood of high-energy gamma rays began its journey to Earth. When they arrived in April, NASA's Fermi Gamma-ray Space Telescope caught the outburst, which helped two ground-based gamma-ray observatories detect some of the highest-energy light ever seen from a galaxy so distant.

Astronomers had assumed that light at different energies came from regions at different distances from the black hole. Gamma rays, the highest-energy form of light, were thought to be produced closest in. But observations across the spectrum suggest that light at all wavelengths came from a single region located far away roughly five light-years from the black hole, which is greater than the distance between our sun and the nearest star.

The gamma rays came from a galaxy known as PKS 1441+25, a type of active galaxy called a blazar. Located toward the constellation Boötes, the galaxy is so far away its light takes 7.6 billion years to reach us. At its heart lies a monster black hole with a mass estimated at 70 million times the sun's and a surrounding disk of hot gas and dust. If placed at the center of our solar system, the black hole's event horizon -- the point beyond which nothing can escape -- would extend almost to the orbit of Mars.

As material in the disk falls toward the black hole, some of it forms dual particle jets that blast out of the disk in opposite directions at nearly the speed of light. Blazars are so bright in gamma rays because one jet points almost directly toward us, giving astronomers a view straight into the black hole's dynamic and poorly understood realm.

In April, PKS 1441+25 underwent a major eruption. Luigi Pacciani at the Italian National Institute for Astrophysics in Rome was leading a project to catch blazar flares in their earliest stages in collaboration with th

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