Gamma rays from the narrow-line Seyfert 1 galaxy PMN J0948+0022 (center) show that its central black hole drives a fast-moving particle beam. The object lies 5.5 billion light-years away in the constellation Sextans.
Brighter colors indicate higher numbers of gamma rays at energies
above 200 million electronvolts.
(Image: NASA/DOE/LAT Collaboration.)
Back in June 1991, just before the launch of NASA's Compton Gamma-Ray Observatory, astronomers knew of gamma rays from exactly one galaxy beyond our own. To their surprise and delight, the satellite captured similar emissions from dozens of other galaxies. Now its successor, the Fermi Gamma-ray Space Telescope, is filling in the picture with new finds of its own.
"Compton showed us that two classes of active galaxies emitted gamma rays—blazars and radio galaxies," said Luigi Foschini at Brera Observatory of the National Institute for Astrophysics in Merate, Italy. "With Fermi, we've found a third,
and opened a new window in the field."
Read more in
the NASA news release...
Bike Helmets—Beyond de Rigueur
"They're not required on Stanford campus, and I ride slowly. Why put on a bike helmet at SLAC?"
A helmet is
required while cycling on SLAC grounds, but more than that, please consider its potential to save your noggin.
A helmet is required when riding a bicycle, moped or scooter at SLAC. (Photo by Brad Plummer.)
Head trauma is the culprit in a majority of bicycle fatalities, and helmet use has been estimated to reduce head injury risk by as much as 85 percent. (See the Insurance Institute for Traffic Facts, below.) A startling 95 percent of bicyclists killed in 2006 were not wearing helmets, according to the Network of Employers for Traffic Safety. At least 698 cyclists were killed and another 44,000 injured in U.S. traffic accidents during 2007, as reported by the National Highway Traffic Safety Administration. Given the statistics, it's a safe bet that bike helmets save thousands of lives every year.
To be effective, a bike helmet must fit properly... and you must of course wear it. The U.S. NHTSA
easy steps to properly fit a bike helmet; and you can buy one at any bike shop. The rest is up to you.
Insurance Institute for Traffic Facts,
2007 Traffic Safety Facts and
NETS Bicycle Safety Resource Center for Employers.
Project Management Training Next Monday
On June 8 from 8:00 a.m. until noon at Kavli Auditorium, the Operations Project Management Office
will provide project management training instructed by Humphrey and Associates in Earned Value Management Systems. The training will encompass project management theory in planning, scheduling,
and managing and measuring performance.
It is required for ARRA project managers, but is open to all other project leaders who would benefit from this training.
For registration information, see the