A cosmic kaleidoscope

At first glance, this cosmic kaleidoscope of purple, blue and pink offers a strikingly beautiful — and serene — snapshot of the cosmos. However, this multi-coloured haze actually marks the site of two colliding galaxy clusters , forming a single object known as MACS J0416.1-2403 (or MACS J0416 for short).

MACS J0416 is located about 4.3 billion light-years from Earth, in the constellation of Eridanus . This new image of the cluster combines data from three different telescopes: the NASA/ESA Hubble Space Telescope (showing the galaxies and stars), the NASA Chandra X-ray Observatory (diffuse emission in blue), and the NRAO Jansky Very Large Array (diffuse emission in pink). Each telescope shows a different element of the cluster, allowing astronomers to study MACS J0416 in detail.

As with all galaxy clusters, MACS J0416 contains a significant amount of dark matter , which leaves a detectable imprint in visible light by distorting the images of background galaxies. In this image, this dark matter appears to align well with the blue-hued hot gas, suggesting that the two clusters have not yet collided; if the clusters had already smashed into one another, the dark matter and gas would have separated. MACS J0416 also contains other features — such as a compact core of hot gas — that would likely have been disrupted had a collision already occurred.

Together with five other galaxy clusters, MACS J0416 is playing a leading role in the Hubble Frontier Fields programme , for which this data was obtained. Owing to its huge mass, the cluster is in fact bending the light of background objects, acting as a magnifying lens . Astronomers can use this phenomenon to find galaxies that existed only hundreds of million years after the big bang .

For more information on both Frontier Fields and the phenomenon of gravitational lensing, see Hubblecast 90: The final frontier .