Image of M100, taken by David Malin with the Anglo-Australian Telescope.
This image shows a portion of the Virgo cluster of galaxies which is dominated by the majestic spiral M100, one of the most beautiful spirals in this cluster. This part of the photograph can be studied in an enhanced magnificient image.
A small companion, NGC 4322, is shown in the upper part of the image. This small galaxy is a representative of a much less spectacular kind of galaxies, a so-called nucleated dwarf ellipcital, and our image is the first color picture of a dwarf galaxy of this type. From this image, we can conclude that although this galaxy is almost certainly in the same cluster as M100, it must not necessarily be close to it. Dwarf galaxies are by far the most common kind in rich clusters such as this, but nucleated examples are unusual, and this is the first color picture to show one.
A deeper AAT image of M100 and its neighborhood in the Virgo Cluster. This image has been created from the same plates that were used to make the above; it shows the much fainter galaxies in the field of M100. In the image enhancement process, the brighter details of the large spiral and the nucleated dwarf galaxy have been lost, and the color of the sky background is rather uneven, but this wider view now shows many other, much fainter galaxies. The nucleated dwarf seen in the image above is now obviously involved with the faint outskirts of the large spiral. The somewhat distorted shape of the dwarf galaxy suggests it could be both influencing and being influenced by M100, and may be the cause of the asymmetry in the spiral arms seen in the previous image.
Nearby is an even fainter, elongated dwarf galaxy and elsewhere in the picture are several others. Near one edge of the photograph is an unusual, slightly irregularly shaped blue dwarf galaxy. More intensive image enhancement of fine-grain, high resolution plates of this part of the sky shows many more, even fainter galaxies than those seen here, suggesting that most members of the Virgo cluster are not bright, eye-catching spirals like M100, or even fuzzy ellipticals, but faint, seemingly insignificant dwarf galaxies.
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Last Modification: April 19, 1998