"This image from NASA's Hubble Space Telescope shows the diverse
collection of galaxies in the cluster Abell S0740 that is over 450
million light-years away in the direction of the constellation
Centaurus. The giant elliptical ESO 325-G004 looms large at the
cluster's center."

"...globular clusters, small compact groups of hundreds of thousands
of stars that are gravitationally bound systems. These clusters are
dispersed spherically and uniformly in the outer halo of the
elliptical and make their way around the center of the galaxy over the
course of millions of years. Several foreground stars and background
galaxies are also visible within the halo of this bright galaxy.

In the course of analyzing this Hubble image, astronomers discovered
that the galaxy ESO325-004 is actually a "gravitational lens." This
means that the focusing power of the enormous mass making up the
galaxy causes the light from some background object, probably a
distant "dwarf" galaxy, to be deflected and magnified. As a result,
the more distant galaxy appears brighter, and distorted into the shape
of an arc, or ring, known as an "Einstein ring" because the phenomenon
was first predicted by Albert Einstein. Although the universe is
filled with galaxies, gravitational lensing is a rare occurrence
because it requires an almost perfect alignment of a distant galaxy
with an intervening one that has enough mass to gravitationally focus
the light.

This particular system is unique because it is closest known example
of strong gravitational lensing."

Hubble

I hope you continue to enjoy and contemplate the wonders of our
universe.
Take care, Vince