symmetry - February 2012 - Going Public

“For three and a half years, the Fermi Gamma-ray Space Telescope has been circling the planet in low-Earth orbit, scanning the sky for evidence of the most energetic objects in the universe. For three and a half years, data captured by Fermi's instruments have been accumulating on a NASA server at Goddard Space Flight Center in Maryland... It's a hybrid project, born of a partnership between astrophysics and high-energy physics, led, not surprisingly, by NASA and the Department of Energy. And when it comes to handling data, most scientists working on the project represent one of two distinct cultures. In particle physics, researchers tend to keep their data close, holding it within their experimental collaborations... They argue that only collaboration members understand the detectors well enough to interpret the data correctly. In astrophysics, big orbiting observatories like NASA's Hubble Space Telescope are generally at the disposal of independent research groups that are awarded blocks of observation time... Observers typically get sole use of the resulting data for a set time period—often a year—before they go public. But the scientists working with Fermi's main instrument, the Large Area Telescope or LAT, do neither. After Fermi's first year in orbit—as much a time to verify that the telescope worked as a data-gathering period—the LAT collaboration posted all of its data online... "Anybody is free to download the data and the software" used to analyze them, says Anders Borgland, a SLAC physicist who leads the data processing team at the laboratory's Instrument Science Operations Center... Once uploaded, the data aren't frozen. Taking a page from high-energy physics experiments, the Fermi data analysis teams continue to learn more about their instruments, using that knowledge to upgrade the analysis software. Once a new version of the software is released all the Fermi data are reanalyzed. The team released data from Pass 7 this summer, after which researchers the world over checked the new data against their old papers to see if revisions were called for... "NASA keeps an archive of the raw data," Michelson says, "but what's released are high-level data—not the raw hits in the calorimeter and the tracker." Some analysis software is made available and the FSSC conducts workshops on how to download the data and use the available tools, but if the tools aren't the right ones in the first place, researchers must develop their own...”