The Sombrero Galaxy (M-104): 

The Sombrero Galaxy or Messier 104 or M-104 or NGC 4594 is a spiral galaxy located 28 million light-years from Earth. It can be located in the constellation Virgo . This galaxy looks like a Mexican Hat (Sombrero) and hence its name.

A galaxy is a system of stars, planets  and stellar remnants which is massive and held together by gravity. It also has  an interstellar medium of gas, dust, and dark matter (which is still not understood very well).  Galaxies range from dwarfs have a few million stars to giants with one hundred trillion stars orbiting their galaxy’s own center of mass. Supermassive black holes reside at the center of most galaxies. Galaxies have been categorised as elliptical galaxies (which are ellipse-shaped), Spiral galaxies which are disk-shaped with curving arm and irregular galaxies that have irregular shapes.  Galaxies which are close together interact with each other , and may ultimately merge. Eg., Our galaxy the Milky way will merge with Andromeda galaxy. There are probably more than 170 billion galaxies in the observable universe. We will observe the Sombrero galaxy this winter through our 12″ telescope (however unlike this Hubble image it will appear just like a line smudged on a chalkboard) during the Astro-camps.

Source: Hubblesite.org