Geminga


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Geminga

(jĕ-ming -gă) An intense gamma-ray source in the constellation Gemini (hence the name), first discovered by the SAS-2 satellite. It is also an X-ray source, but more than 99% of its power output is observed in the γ-ray spectral range. Recent observations with the X-ray satellite ROSAT and the Compton Gamma Ray Observatory have revealed that Geminga is a gamma-ray pulsar with a period of 237 milliseconds; this periodicity has been confirmed by the analysis of archive data from COS-B and SAS-2. Geminga is possibly the result of a nearby supernova.

Geminga

[′jem·iŋ·gə]
(astronomy)
A relatively nearby neutron star, about 150 parsecs (450 light-years) distant, that emits pulsed x-rays and gamma rays (making it an x-ray and gamma-ray pulsar), steady optical radiation, and possible unconfirmed radio and optical pulsations.
The term is derived from Gemini gamma-ray source.
References in periodicals archive ?
Combining 1970s observations of Geminga taken by the COS-B satellite with new data taken by the Compton Gamma Ray Observatory, Mattox found a tiny variation in the arrival time at Earth of gamma rays emitted by the compact body.
An interaction between the core of Geminga and its surface could slow or speed the remnant at irregular intervals.
The measurement indicates that PSR J0437-4715 vies with only one other pulsar, the once-mysterious Geminga - now estimated to lie within 300 light-years of Earth - as the closest pulsar to the solar system (SN: 1/2/93, p.
If further work verifies that the birth of Geminga was indeed a holey event, it could shed new light on the nature of this pulsating star, as well as on the evolution of the interstellar medium surrounding the sun and its neighbors.
A key piece of the puzzle came to the fore earlier this year, when other astronomers discovered that Geminga wasn't the oddball it had seemed.
But when might the explosion that formed Geminga have occurred?
To pin down Geminga's location at birth, Gehrels and Chen relied on another team's comparison of new and older observations of Geminga in visible light.
Both the general location and the time of the explosion make Geminga a promising candidate for creator of the local bubble, he asserts.
This was a big mystery for a long time because Geminga could not be identified with anything else at any other wavelength," says astronomer Charles D.
Using data collected by instruments aboard orbiting observatories, astronomers have now detected pulsations in Geminga's gamma-ray emissions, allowing them to match Geminga with a weak, pulsating X-ray source and an extremely faint, visible-light source in the same part of the sky.
With this discovery, we consider the mystery of Geminga largely solved," Jules P.
Using data from the orbiting X-ray observatory ROSAT, Halpern and Holt showed that the X-ray source in the same neighborhood as Geminga pulsates with a 0.