The Densest Galaxy
4.10.2013

The bright core and outer reaches of giant elliptical galaxy M60 (NGC 4649) loom large at the upper left of this sharp close-up from the Hubble Space Telescope. Some 54 million light-years away and 120,000 light-years across, M60 is one of the largest galaxies in the nearby Virgo Cluster.

Gamma Ray Earth and Sky
6.12.2013

For an Earth-orbiting gamma-ray telescope, Earth is actually the brightest source of gamma-rays, the most energetic form of light. Gamma-rays from Earth are produced when high energy particles, cosmic rays from space, crash into the atmosphere.

Optical Transient Near GRB970508 Shows Distant Redshift
13.05.1997

The GRB distance scale controversy may have just ended with a flash. Gamma Ray Bursts (GRBs) are powerful explosions occurring in seemingly random positions on the sky. They are so featureless and so poorly resolved, however, that their distances could not be determined.

The GRB 110328A Symphony
19.04.2011

A symphony of planet-wide observations began abruptly on March 28 when the Earth-orbiting Swift satellite detected a burst of high-frequency gamma-rays from GRB 110328A. When the same source flared again after a 45 minute pause it was clear this event was not a typical gamma-ray burst.

Neutrinos in the Sun
5.06.1998

Neutrinos, along with things like electrons and quarks, are fundamental pieces of matter according to physicists' Standard Model. But neutrinos are hard to detect. Readily produced in nuclear reactions and particle collisions, they can easily pass completely through planet Earth without once interacting with any other particle.

Abell 370: Galaxy Cluster Gravitational Lens
28.08.2016

What is that strange arc? While imaging the cluster of galaxies Abell 370, astronomers had noted an unusual arc to the right of many cluster galaxies. Although curious, one initial response was to avoid commenting on the arc because nothing like it had ever been noted before.

NGC 1365: Barred Spiral Galaxy
8.10.1999

NGC 1365 is a giant barred spiral galaxy about 200,000 light-years in diameter and 60 million light-years distant in the southern constellation Fornax. These three recently released images offer views of this majestic island universe in visible and infrared light.

ROSAT Explores The X-Ray Sky
8.10.1996

Launched in 1990, the orbiting ROSAT observatory explored the Universe by viewing the entire sky in x-rays - photons with about 1,000 times more energy than visible light. This ROSAT survey produced the sharpest, most sensitive image of the x-ray sky to date.

Fermi s Gamma Ray Sky
21.03.2009

Scanning the entire sky in gamma-rays, photons with over 50 million times the energy of visible light, the Fermi mission's Large Area Telescope (LAT) explores the high-energy universe. This all-sky map constructed from...

ROSAT Explores The X-Ray Sky
19.08.2000

Launched in 1990, the orbiting ROSAT observatory explored the Universe by viewing the entire sky in x-rays -- photons with about 1,000 times more energy than visible light. This ROSAT survey produced the sharpest, most sensitive image of the x-ray sky to date.