Early 'peas' discovered behind the Galaxy Cluster SMACS 0723 by Webb

The chemical fingerprints of chosen galaxies behind SMACS 0723 were captured by the James Webb Space Telescope's Near-Infrared Spectrograph, which included three faint, distant objects. 

In the deep image of the galaxy cluster SMACS 0723 captured by the Webb, a trio of faint objects (circled) display properties remarkably similar to rare, small galaxies called “green peas” found considerably closer to home.

Due to the cluster's mass, it acts as a gravitational lens, which both enlarges and warps the appearance of background galaxies. 

We see these early peas as they existed when the universe was about 5% of its present age of 13.8 billion years. 

It's possible that the furthest pea, on the left, is the most chemically primitive galaxy yet discovered.  It contains just 2% of the oxygen abundance of a galaxy like our own.

Alongside an infrared image of an 'early pea' taken by NASA's James Webb Space Telescope, a 'green pea galaxy' obtained by the Sloan Digital Sky Survey is displayed.

A green pea, J122051+491255, is shown at left.  It is about 170 million light-years away and about 4,000 light-years across, a typical size.

An early pea known as 04590 is shown at right, whose light has taken 13.1 billion years to reach us. 

Compensating for the cluster’s gravitational lensing effect and the galaxy’s greater distance to us, the early pea '04590' is even more compact, comparable to the smallest nearby green peas.

The chemical fingerprints of chosen galaxies behind SMACS 0723, including three faint, far-off objects were captured by the Webb Space's Near-Infrared Spectrograph.

When corrected for the wavelength stretch caused by the expansion of space over billions of years, the spectra of these galaxies (shown in red) display features emitted by oxygen, hydrogen, and neon that show a stunning resemblance to those seen from so-called green pea galaxies (in green) found nearby.

Furthermore, it was possible to measure the oxygen content in these cosmic dawn galaxies for the first time thanks to the Webb observations. To clarify these relationships, the spectral lines have been stretched vertically. Credit: SDSS and NASA, ESA, CSA, and STScI

Read Prinsli World All Stories