Acknowledgement: Judy Schmidt
Galaxies can take many forms — elliptical blobs, swirling spiral
arms, bulges, and discs are all known components of the wide range of
galaxies we have observed using telescopes like the NASA/ESA Hubble
Space Telescope. However, some of the more intriguing objects in the
sky around us include ring galaxies like the one pictured above — Zw II
28.
Ring galaxies are mysterious objects. They are thought to form when
one galaxy slices through the disc of another, larger, one — as
galaxies are mostly empty space, this collision is not as aggressive or
as destructive as one might imagine. The likelihood of two stars
physically colliding is minimal, and it is instead the gravitational
effects of the two galaxies that causes the disruption.
This disruption upsets the material in both galaxies, causing it to
redistribute to form a dense central core, encircled by bright stars.
All this commotion causes clouds of gas and dust to collapse and
triggers new periods of intense star formation in the outer ring, which
is thus full of hot, young, blue stars and regions that are actively
giving rise to new stars.
The sparkling pink and purple loop of Zw II 28 is not a typical ring
galaxy due to its lack of a visible central companion. For many years
it was thought to be a lone circle on the sky, but observations using
Hubble have shown that there may be a possible companion lurking just
inside the ring, where the loop appears to double back on itself. The
galaxy has a knotty, swirling ring structure, with some areas appearing
much brighter than others.
A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Judy Schmidt.
