Although the Fermi Gamma-ray Space Telescope is primarily a gamma-ray instrument, its most cited paper reports a measurement of the combined electron and positron cosmic-ray spectrum. Now a team, led by KIPAC researchers, has built on this result by using a novel technique to separate the cosmic-ray electrons and positrons and measure the spectrum of each component individually. The result will keep theorists busy thinking about pulsars and dark matter.
May 5, 2015 | Let the Sun Shine (In Gamma Rays) II
Unifying the astronomically near and far, the Fermi Gamma-ray Space Telescope has seen its first signature of cosmic rays interacting with the light from our Sun.
The left panel shows the LAT gamma rays per pixel from near the Sun and the right panel shows the same for another patch of sky. There is a clear large flux from the solar disk and a less dense but extended flux surrounding it.
Huge natural thermonuclear explosions, so called stellar novae, are observed in binary systems consisting of a dense compact white dwarf circling a star. The Fermi LAT has for the first time ever detected gamma-ray emission from such an event. This observation indicates particle acceleration in the shock wave produced by the nova explosion to at least GeV energies.
May 5, 2015 | Simulating Stimulating Bursts of Gamma Rays
Using powerful computer simulations, a KIPAC scientist explores the possible mechanisms behind the gamma-ray emission in the super explosions known as gamma-ray bursts.
Artist's conception of a GRB. We see the burst of gamma rays if the jets are oriented so that one points toward us. (Image courtesy of NASA)
May 5, 2015 | Cutting-Edge Physics Computing Is No Game
Ever resourceful, physicists, including several KIPAC scientists, have been using the specialized processors in computer graphics display cards to speed up some of the calculations that arise in data analysis. In the coming era of large astronomical surveys for weak lensing constraints on dark energy, such speed will be essential.
Among the successes of the Fermi Gamma-ray Space Telescope is its discovery of the gamma-ray emission from many pulsars, the fascinating beacons in space. Additionally, KIPAC scientists have also used what Fermi has not seen from some pulsars to learn more about them.
May 5, 2015 | Hard X-rays Reveal Powerful Objects Near and Far
Creating the first ever catalog of the entire Galactic plane in hard x-rays, a KIPAC scientist has paved the way for a deeper understanding of the most luminous compact objects in our Galaxy, and of the x-ray emission from other galaxies.
Map of catalogued hard x-ray emitters in the Galactic center region with their significance in signal to noise
May 5, 2015 | Fermi Telescope Sees Blazin' Blazar
KIPAC scientists have used Fermi Gamma-ray Space Telescope observations to detect a flare in a distant active galaxy, with it becoming temporarily the brightest gamma-ray source in the entire sky, and indicating the most luminous object, aside from gamma-ray bursts, discovered in the Universe to date.
May 5, 2015 | Fermi Space Telescope Sees the Andromeda Galaxy
For the first time, thanks to the Fermi Space Telescope, high energy gamma rays gave been detected coming from another spiral galaxy much like our own Milky Way. It is now evident that the differences in gamma-ray luminosity among galaxies show that the density of cosmic rays varies and is correlated with the formation of new stars.
May 5, 2015 | Fermi Sees Giant Gamma-Ray 'Bubbles' in the Milky Way
The Fermi Gamma-Ray Space Telescope has seen giant unexpected gamma-ray structures in the center of our Milky Way galaxy. The structures, which protrude above and below the Galactic plane in the center of the Galaxy like two opposing bubbles being blown up, are approximately 50,000 light-years tall.
An all-sky map of gamma-ray emission as seen by the Fermi LAT, showing the Galactic diffuse component and the bubbles.
May 5, 2015 | Let the Sun Shine (In Gamma Rays)
The Fermi Gamma-ray Space Telescope, famous for probing the Galaxy and distant reaches of the Universe, has now seen its first flare from our own Sun.
Ultraviolet light image of a solar flare, seen as a bright patch by NASA's Solar Dynamics Observatory (SDO) satellite. One of the three main instruments on SDO was built at Stanford.
The extent to which the cool, dense gas at the centers of massive galaxy clusters can be disrupted remains an outstanding question in astrophysics. Although physical processes such as mergers and central galaxy activity have been shown to suppress cooling and therefore star formation in the central gas, the cool core has almost always been observed to remain more or less intact. Recently, however, a team of KIPAC researchers has found the most extreme example yet of these processes disrupting the core.