Credit: NASA/UCSB/C.Martin et al. & NOAO/KPNO/C.Martin; CXC/M.Weiss

Dwarf's Gift

Stars produce the chemical elements important for life. In galaxies, stars seed the interstellar medium with oxygen, silicon, magnesium, nitrogen, and other elements (which astronomers call "metals") necessary for life. An open question is whether and how galaxies themselves can pollute the space between galaxies with these elements. A new observation by the Chandra X-ray Observatory has shown how this process might be done. The image on the left above shows a composite X-ray and optical image of the dwarf galaxy NGC 1569. This galaxy is undergoing a burst of star formation and as these stars explode as supernova they produce metals which get ejected into space; because this is a dwarf galaxy, it's relatively easy for this fast-moving ejecta to escape the into intergalactic space. The green color shows X-rays from multimillion degree Celsius gas heated by shock waves extending for large distances away from the galaxy. Chandra shows that this gas is enriched in metals, containing (for example) an amount of oxygen quivalent to 3 million suns. The red color shows the optical light from warm gas heated by the ultraviolet light from massive stars. Large loops of the warm gas can be seen extending above and below the disk of the galaxy. The picture on the right shows the orientation of NGC 1569 and its X-ray emitting lobes and the observation direction.

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Page Author: Dr. Michael F. Corcoran
Last modified July 29, 2002