HSC J023336-053022, a massive galaxy cluster located approximately 4 billion light-years away from Earth, is heating the material within it to hundreds of millions of degrees Celsius — over 25 times hotter than the core of the Sun.
This composite image shows the galaxy cluster HSC J023336-053022, also known as ACT-CL J0233.6-0530 or XLSSC 105. Image credit: Green Bank Observatory / National Science Foundation / Subaru Telescope / National Astronomical Observatory of Japan / HSC-SSP Collaboration / ESA / XMM-Newton / XXL Survey Consortium.
Galaxy clusters contain thousands of galaxies of all ages, shapes and sizes.
Typically, they have a mass of about one million billion times the mass of the Sun and form over billions of years as smaller groups of galaxies slowly come together.
Different sub-groups of galaxies can also form within a single cluster, as in the case of HSC J023336-053022.
Two blue-purple circles in the composite image above mark the locations of two sub-clusters within HSC J023336-053022 which are slowly moving towards and colliding with one another, ‘shock heating’ gas to intense temperatures in the process.
To create this image, three different international teams of astronomers explored observations of the cluster across the electromagnetic spectrum, in order to isolate and pinpoint different aspects of this region of space.
These aspects are shown here in different colors:
(i) individual galaxies within the cluster show up in orange;
(ii) dark matter, which maps the location of the two sub-clusters, in blue;
(iii) hot, dense gas shows up in green, while hot, thin, high-pressure gas shows up in red; this gas is something known as the ‘intracluster medium,’ which permeates galaxy clusters and fills the space between galaxies.
The addition of radio observations makes this image of HSC J023336-053022 special, as many studies of collisions within or between galaxy clusters have not captured this shock-heating process — which is represented visually in the region where green changes to red — in radio.
This process releases immense amounts of energy and heats already scorching gas to temperatures tens of times hotter.
Before shock heating, the gas sits at around 40 million degrees Celsius — already some 2.7 times hotter than the core of the Sun.
