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The All-Sky Search

Data Analysis

Einstein@Home screensaver  
The Einstein@Home screen saver has many elements related to the gravitational wave search: the locations of LIGO and GEO 600, the locations of known objects that probably emit gravitational waves, and the area of the sky your computer is studying.

The basis of the screen saver is a rotating celestial sphere. A celestial sphere is a projection of what the sky would look like if the stars were attached to a sphere surrounding the earth. The major stars in each constellation are shown on the sphere, but remember that they will look different than you might be used to because you are seeing them from outside the celestial sphere instead of from the earth.

LIGO and GEO 600

“L” shaped markers shown the locations on the sphere directly above the two LIGO observatories and GEO 600. The "L" shape reflects the design of the detectors. Although the orientations of the detectors are correct, they are not to scale.

LIGO Hanford Observatory

LIGO Hanford Observatory (LHO)
Hanford, Washington, USA, (N 46.45°, W 119.41°)
consisting of two interferometers, one with 4km arms (H1) and one with 2km arms (H2).

LIGO Livingston Observatory

LIGO Livingston Observatory (LLO)
Livingston, Louisiana, USA, (N 30.56°, W 90.77°)
consisting of one interferometer with 4km arms (L1).


Hanover, Germany, (N 52.24°, E 9.81°)
consisting of one interferometer with 600m arms.

If your system clock is set to the correct time, the detectors will be shown in proper relation to the stars. They move around the celestial sphere once in 24 hours.

Pulsars and Supernovae Remnants

Pulsars and Supernovae are shown on the sky because scientists believe they emit gravitational waves. The purple dots on the celestial sphere mark the locations of pulsars* that have already been detected. These are clustered in the plane of our galaxy, the Milky Way, and are mostly near the center of the galaxy. They are likely sources of gravitational waves.

Dark red dots mark the locations of supernova remnants**. These are also concentrated near the center of the galaxy. Supernovae remnants can leave behind pulsars or spinning neutron stars that may produce gravitational waves.

Area being processed

Search MarkerThe area of sky being processed on your computer is shown as a small moving circle with a cross drawn through it. The coordinates for this location are given in the lower right-hand corner of the screen. You should see this marker move as the search progresses.

* Pulsar: A dense, rapidly rotating star that emits pulses of light.

** Supernova remnants: What is left after a heavy star violently explodes.

Information and Graphics Courtesy of:

Eric Myers
Dept. of Physics
and Astronomy
Vassar College

David Hammer
Dept. of Physics
University of Wisconsin at Milwaukee

Bruce Allen
Dept. of Physics
University of Wisconsin at Milwaukee

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