James Webb Space Telescope Uncovers Epic Prequel to Enormous Galaxy Cluster

April 24, 2023

NASA's James Webb Space Telescope has made a groundbreaking discovery that sheds light on the formative years of the universe. For the first time, the telescope has confirmed the existence of a protocluster of seven galaxies that formed just 650 million years after the big bang. This cluster, at a distance referred to as redshift 7.9, was observed using Webb's Near-Infrared Spectrograph (NIRSpec), which captured precise measurements of the galaxies' collective distance and high velocities of more than 2 million miles per hour.

The data collected has allowed astronomers to model and map the future development of the gathering group, and the prediction is that it will eventually resemble the Coma Cluster, one of the densest known galaxy collections with thousands of members. This discovery was made possible because Webb's infrared instruments were specifically developed to fill gaps in our knowledge of the universe's story at the beginning of time.

Exploring how large clusters like Pandora and Coma first came together has been difficult because the universe's expansion stretches light beyond visible wavelengths into the infrared, where high-resolution data was lacking before Webb. This discovery is a significant step forward in our understanding of the universe's early development, and future collaboration between Webb and NASA's Nancy Grace Roman Space Telescope is expected to yield even more results on early galaxy clusters. 

The discovery of the protocluster of seven galaxies is a significant breakthrough in the field of astrophysics as it offers valuable insight into the early formation of galaxies. The fact that the protocluster was observed just 650 million years after the big bang means that it is one of the earliest known examples of such a phenomenon.

According to Takahiro Morishita of IPAC-California Institute of Technology, the lead author of the study published in the Astrophysical Journal Letters, this protocluster is a "very special, unique site of accelerated galaxy evolution." The study used the spectral data collected by Webb's NIRSpec to measure the velocities of the galaxies and confirm that they are bound together in a protocluster.

One of the key findings of the study is the protocluster's future development, which is expected to resemble the Coma Cluster, a massive collection of galaxies in the modern universe. The prediction is that the protocluster will grow in size and mass over time to become one of the densest known galaxy clusters.

The research team used the gravitational lensing effect of the Pandora's Cluster to view the protocluster, even though it is located at such a great distance. This technique involves using the gravitational pull of the cluster to magnify and distort the light from background objects, enabling astronomers to study them in more detail.

In addition to its significance in the field of astrophysics, this discovery also highlights the capabilities of the James Webb Space Telescope. Webb's powerful infrared instruments were specifically developed to study the early universe and fill gaps in our knowledge of its formation. The telescope's success in observing the protocluster of seven galaxies demonstrates its ability to make groundbreaking discoveries in the field.

Looking ahead, the research team expects that future collaboration between Webb and NASA's Nancy Grace Roman Space Telescope will yield even more results on early galaxy clusters. The Roman mission is set to launch by May 2027 and will have 200 times Hubble's infrared field of view in a single shot, allowing it to identify more protocluster galaxy candidates. Webb will then be able to follow up on these candidates with its spectroscopic instruments and confirm their existence.

Source - NASA