GSFC: Fermi Traces the History of Starlight across the Cosmos
Posted: Sun Dec 02, 2018 10:06 pm
Fermi Traces the History of Starlight across the Cosmos
NASA | Goddard | Fermi | 2018 Nov 29
Scientists Measure All of the Starlight Ever Produced by Universe
Clemson University | 2018 Nov 29
Clues from gamma rays on the history of star birth
Science Perpective | Elisa Prandini | 2018 Nov 30
A gamma-ray determination of the Universe’s star formation history ~ Fermi-LAT Collaboration
NASA | Goddard | Fermi | 2018 Nov 29
Scientists using data from NASA’s Fermi Gamma-ray Space Telescope have measured all the starlight produced over 90 percent of the universe’s history. The analysis, which examines the gamma-ray output of distant galaxies, estimates the formation rate of stars and provides a reference for future missions that will explore the still-murky early days of stellar evolution. ...Click to play embedded YouTube video.
One of the main goals of the Fermi mission, which celebrated its 10th anniversary in orbit this year, was to assess the extragalactic background light (EBL), a cosmic fog composed of all the ultraviolet, visible and infrared light stars have created over the universe’s history. Because starlight continues to travel across the cosmos long after its sources have burned out, measuring the EBL allows astronomers to study stellar formation and evolution separately from the stars themselves. ...
The collision between a high-energy gamma ray and infrared light, for example, transforms the energy into a pair of particles, an electron and its antimatter counterpart, a positron. The same process occurs when medium-energy gamma rays interact with visible light, and low-energy gamma rays interact with ultraviolet light. Fermi’s ability to detect gamma rays across a wide range of energies makes it uniquely suited for mapping the EBL spectrum. Enough of these interactions occur over cosmic distances that the farther back scientists look, the more evident their effects become on gamma-ray sources, enabling a deep probe of the universe’s stellar content. ...
Scientists Measure All of the Starlight Ever Produced by Universe
Clemson University | 2018 Nov 29
Clues from gamma rays on the history of star birth
Science Perpective | Elisa Prandini | 2018 Nov 30
A gamma-ray determination of the Universe’s star formation history ~ Fermi-LAT Collaboration
- Science 362(6418):1031 (30 Nov 2018) DOI: 10.1126/science.aat8123