Messier 77 - Seyfert- Galaxy
The galaxy "Messier 77" with a brightness of 8.9mag and an apparent size of 6'x6' is located in the constellation of Cetus at a distance of
about 47 million light years. It was discovered in 1780 by Pierre Méchain and lies almost directly on the celestial equator with a declination
of -00° 01'.
Messier 77 is of Hubble type "SAa" - that means the galaxy belongs to the group of spiral galaxies with tightly wrapped spiral arms. In the
center there is an active nucleus, so the galaxy is not only a radio source (Cetus A), but also counts as a "Seyfert type 2" galaxy. In the center
a disk of warm dust was discovered, with temperatures of 250K in the outer regions and even up to 1500K in the inner regions. This dust torus
prevents a direct view of the center of Messier 77, where a supermassive black hole (SMBH) of 15 million solar masses is suspected.
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In my 20" telescope, Messier 77 is a beautiful sight. It is very bright and shows many exciting structures at a magnification of 270x.
First of all, the central region is quite luminous and in the very center you can see a very bright stellar nucleus - an indication of the galaxy's AGN.
The spiral arms appear very distinct and wrap tightly around the nucleus. In very steady air, two brighter spots can be seen in the arms - possibly
HII regions. Messier 77 is surrounded by a very faint, widespread halo with a very low surface brightness. It takes a dark sky to see this halo.
