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NGC 4736

A spiral galaxy in the constellation of Canes Venatici, lying near the star Cor Caroli in the sky, directly southward from the handle of the Plough in Ursa Major. M94, which is some 16 million light years from the Milky Way Galaxy, is angled almost exactly face-on, so that the details of its spiral structure can be very clearly seen.

The details of that spiral structure are remarkable and unusual. In the galaxy's core is an elliptical feature that sends out pressure waves of gas into the galaxy, and the result is a distinctive starburst region ringing the galaxy's nucleus. Matter in this starburst ring is compacted by the pressure wave from the core, causing intense star-forming activity and creating a sparkling ribbon of young stars in a near-circular pattern surrounding the galaxy's central regions. This ring of new stars passes through spiral arms within the central galaxy, but beyond this central spiral, M94 presents a secondary spiral structure. A further set of long, tenuous arms spiral out for some 30,000 light years from the galactic nucleus, making this effectively a double spiral galaxy.

M94 gives its name to the galaxy group that contains it. This M94 Group (also called the Canes Venatici I Group) is made up of about twenty galaxies close enough in space to be gravitationally bound to one another. This group is one of the closest such collections of galaxies to the Milky Way's Local Group, and like the Local Group it forms part of the greater Virgo Supercluster.


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