Explanation:
NGC 1132 is one smooth galaxy -- but how did it form?
As an
elliptical galaxy,
NGC 1132 has little dust and gas, and few stars have formed in it recently.
Although many elliptical galaxies are in clusters of galaxies, NGC 1132
appears as a large, isolated galaxy toward the constellation of
the River (Eridanus).
To probe the history of this intriguing trillion-star ball, astronomers imaged
NGC 1132 in both
visible light with the
Hubble Space Telescope and
X-ray light with the
Chandra X-ray Observatory.
In this composite false-color image, visible light is white,
while the X-ray light is blue and indicates the unusual
presence of very hot gas.
The X-ray light also likely traces out the location of
dark
matter.
One progenitor hypothesis is that NGC 1132 is the result of a series of
galaxy mergers in what once was a small
group of galaxies.
NGC 1132 is over 300 million light years away, so the light we see
from it today left before
dinosaurs
roamed the Earth.
Many
fascinating background galaxies
can be seen far in the distance.
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