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 Space Telescope Sees the Andromeda Galaxy
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.
May 5, 2015 | Scientists TCB With Simulated GRBs
By realistically simulating a population of gamma-ray bursts, KIPAC scientists have demonstrated the extent to which these explosions can be mischaracterized when they are far away.
The observed duration of a GRB pulse as a function of distance (redshift) for both an ideal (Without Noise) and a realistic (With Noise) observing instrument. The actual observed duration deviates from the expected duration.
May 5, 2015 | The Arias of Universes in a Box
Simulating the evolution of the early Universe on computers is the starting point for cosmologists' understanding of structure formation in the cosmos. With techniques to pursue both a large volume of simulated universe and high spatial resolution, KIPAC researchers are leading the charge against one of the foremost computational challenges in astrophysics.
The only way to accurately predict the conditions near black holes is with extensive computer simulations of the complicated physics involved. While black holes are the quintessential manifestation of Einstein's General Relativity, very few precision tests of the theory have been based on actual observations of black holes. New simulation results point to an observable property of such systems that could be used as a precision test of Einstein's theory.
May 5, 2015 | Nomadic Planets May Swarm the Galaxy
Much public attention has focused on the recent discoveries of many hundreds of planets around other stars. A group of KIPAC scientists has now estimated that there may be up to ten thousand times as many planet-sized objects flying freely through our Galaxy as there are planets orbiting stars. They explore the implications for future sky surveys such as LSST, as well as our view of planet formation and even the origin of life.
May 5, 2015 | Shapes of Galaxies on the Brain
KIPAC astrophysicists have used a technique that processes information in a way analogous to the human brain in order to determine whether galaxy shapes can help determine their place in the Universe.
The effect of adding multiple parameters representing galaxy shape information on the photo-z accuracy, as determined by Singal et al. with their neural network method.
Centaurus A (Cen A) is one of the brightest radio sources in the sky: it is a giant elliptical Galaxy about 10 million light years away, making it the closest active galaxy we know. A remarkable feature of the radio image of this galaxy is that the bright central source is accompanied by a pair of giant radio "lobes," thought to be fuelled by relativistic jets generated in the dynamical process of gas accretion around the super-massive black hole residing at the galaxy's center.
Photometric redshift determination is crucial to the success of dark energy missions such as LSST and DES. A KIPAC postdoc has developed an important tool for photometric redshift estimation and applied it to 60 million galaxies from the Sloan Digital Sky Survey.
Six randomly chosen galaxies' photometric redshift probability distributions from Cunha and colleagues' SDSS galaxy sample.
May 5, 2015 | Fermi LAT constrains dark matter in galaxy clusters
Clusters of galaxies are the most massive structures in the universe. Most of the mass in these clusters is considered to be dark matter. The Fermi LAT monitors these clusters for a gamma-ray signal from dark matter annihilation. No such signal has been found yet, but the non-observation starts to constrain a wide range of proposed dark matter models.