Researchers using the Hubble Space Telescope have captured a detailed image of the elliptical galaxy PGC 6240 located in the southern constellation of Hydrus (The Water Snake).
Roughly resembling a pale rose, the galaxy contains several hazy shells encircling its bright center. Some of the shells are located near the middle of the galaxies while others lie farther out into space -- the very farthest appearing almost detached.
The structure is one that has long compelled astronomers who have studied it extensively. Its surrounding globular clusters, full of dense and tightly packed groups of stars bound by gravity, have also been a subject of curiosity.
Globular clusters orbit galaxies, including our own: in all, 150 make their way around the Milky Way. Because the clusters around a galaxy and the stars within them are born around the same time, those found around the Milky Way share a similarly old age.
PGC 6240 is unusual, however -- the ages of its clusters are varied, with some containing the expected old stars and others younger stars formed relatively recently.
Though the reason for this and the galaxy's stacked shell structure is unclear, one theory states that PGC 6240 merged with another galaxy within the recent past, creating ripples throughout the galaxy that disrupted the structure and resulted in concentric shells.
Such a merger would have triggered star formation both in the galaxy and nearby space -- hence the younger clusters.
Also featured in the image are an array of background galaxies, including spiral galaxies.
Other recent observations made by the researchers include an image of the Abell 1689 galaxy cluster. Called one of the best images ever taken of the cluster, it calls the phenomenon of gravitational lensing into attention. In gravitational lensing, the cluster acts like a lens as it magnifies the light from the objects behind it, allowing scientists to study the area in greater detail.