Thursday, August 11, 2005

Midsummer's Dream Galaxies

Images of Two Magnificent Spiral Galaxies from ESO Data Archive

Spiral Galaxy NGC 4565, which for obvious reasons is also called the Needle Galaxy.
First spotted in 1785 by Uranus' discoverer, Sir William Herschel (1738-1822), this is one of the most famous example of an edge-on spiral galaxy and is located some 30 million light-years away in the constellation Coma Berenices (Berenice's Hair).
It displays a bright yellowish central bulge that juts out above most impressive dust lanes.
Because it is relatively close (it is only 12 times farther away than Messier 31, the Andromeda galaxy, which is the major galaxy closest to us) and relatively large (roughly one third larger than the Milky Way), it does not fit entirely into the field of view of the FORS instrument (about 7 x 7 arcmin2).
Many background galaxies are also visible in this FORS image, giving full meaning to their nickname of "island universes".
Spiral Galaxy Messier 83.
If our Milky Way were to resemble this one, we certainly would be proud of our home!
The beautiful spiral galaxy Messier 83 is located in the southern constellation Hydra (the Water Snake) and is also known as NGC 5236 and as the Southern Pinwheel galaxy.
Its distance is about 15 million light-years. Being about twice as small as the Milky Way, its size on the sky is 11x10 arcmin2.
The image show clumpy, well-defined spiral arms that are rich in young stars, while the disc reveals a complex system of intricate dust lanes. This galaxy is known to be a site of vigorous star formation.

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