What it Means
NASA, the Stanford Linear Accelerator Group, and Sonoma State University jointly announced yesterday that their mission, the Gamma-ray Large Area Space Telescope (formerly known as GLAST) is now going by the name Fermi, and it has a nifty new logo to celebrate. I think the incorporation of a stylized active galactic nucleus and a spiraling jet is quite clever.
The spacecraft’s new name honors THE pioneer in high-energy physics, quantum theory, and particle physics, Italian scientist Enrico Fermi, who lived from 1901 to 1954. He was the first person to figure out how cosmic particles could be accelerated to the high speeds that take them across the universe, and if he had lived to see the telescope that bears his name, he would have been delighted to study the pulsars in our galaxy and the gamma-ray signals from supermassive black holes at the cores of galaxies. His work set the stage for understanding the phenomena we see at these cosmic objects.
Fermi the spacecraft was launched two months ago and has been in testing and calibration mode since then. To celebrate the renaming, Fermi scientists used the Large Area Telescope onboard the spacecraft to “take” an all-sky image showing the glowing gas of the Milky Way, blinking pulsars, and a flaring galaxy billions of light-years away. It’s the result of 95 hours of the instrument’s “first light” observations. By comparison, when NASA’s now-defunct Compton Gamma-ray Observatory, did the same image, it took years of observations to create.
This Fermi image shows gas and dust in the plane of the Milky Way glowing in gamma rays due to collisions with accelerated nuclei called cosmic rays. The famous Crab Nebula and Vela pulsars also shine brightly at these wavelengths. These are fast-spinning neutron stars, which form when massive stars die. The Crab and Vela pulsars were originally discovered by their radio emissions. The third pulsar shown here, named Geminga and located in Gemini, is not a radio source. It was discovered by an earlier gamma-ray satellite. Fermi is expected to discover many more radio-quiet pulsars, providing key information about how these exotic objects work.
A fourth bright spot in the LAT image lies some 7.1 billion light-years away, far beyond our galaxy. This is 3C 454.3 in Pegasus, a type of active galaxy called a blazar. It’s now undergoing a flaring episode that makes it especially bright. Another instrument onboard the spacecraft, the GBM, has already been recording gamma-ray bursts that occur when massive stars die or neutron stars merge.
At the rate Fermi is studying the sky, I don’t think it will be too long before we start seeing a new set of cosmic images that will bring us new views of the universe in much the same way that the Compton Gamma-ray Observatory did in its heydey.
s material along ahead of it), or even a supernova blast, and the cloud starts clumping together and swirling around. Eventually the material in the center, which is being compressed by the motion, will heat up. If this happens long enough and there’s enough material to keep the clumping going, a star will eventually form. This is a very simple explanation for a complex set of processes that take hundreds of thousands of years to start a cloud down the path of starbirth.