James Webb’s Ultra Deep Field Observations: Two Research Teams to Study Earliest Galaxies  

James Webb Space Telescope (JWST), the space observatory designed to conduct infrared astronomy and launched successfully on 25 December 2021 will enable two research teams to study earliest galaxies in the universe. The research teams will use JWST’s powerful instruments (NIRISS, NIRCam and NIRSpec) to capture and characterize some of the earliest galaxies. 

The Next Generation Deep Extragalactic Exploratory Public (NGDEEP) Survey will target Hubble Ultra Deep Field by pointing telescope’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) on the primary Hubble Ultra Deep Field and Near-Infrared Camera (NIRCam) on the parallel field. The two instruments NIRISS and NIRCam will capture infrared light (redshifted due to expansion of universe). The data will be released immediately to benefit the researchers.  

NGDEEP team will also identify metal elements in the early galaxies especially in smaller and dimmer ones that haven’t yet been thoroughly studied so far. Study of metal contents of galaxies is standard way to trace evolution across cosmic time. There were only hydrogen and helium in the beginning of the universe. New elements were formed by successive generations of stars. Studying metal contents of galaxies will help to plot out precisely when various elements existed and update models that project how galaxies evolved in the early universe. 

The other research team will examine the primary Hubble Ultra Deep Field using the microshutter array within the telescope’s Near-Infrared Spectrograph (NIRSpec). This will provide first large sample of earliest galaxies that existed in the early universe enabling researchers to understand them in detail.  

The story of study of early universe began in 1995 with the decision to focus Hubble Space Telescope (HST) on nothing in the hitherto unexplored field in the sky. Hubble captured about 3000 images of galaxies at different stages of stellar evolution. Better known as Hubble Deep Field, these images were first pictures of early galaxies and revolutionised the field of astronomy.  

As a successor of Hubble space telescope (HST), James Webb Space Telescope (JWST) is carrying forward the Hubble telescope’s legacy in the area of study of early universe. Webb telescope aims to search for light from the first stars and galaxies that formed in the Universe after the Big Bang to study the formation and evolution of galaxies, to understand the formation of stars and planetary systems and to study planetary systems and the origins of life. 

The early universe in the first several hundred million years after the big bang was a very different place. It was semi-opaque. This is when the first galaxies in the universe were beginning to form. Many distant galaxies have been spotted by the telescopes but none earlier than 400 million years after the big bang. What were galaxies that existed even earlier like? The above mentioned, two research teams will answer just this by revealing details of the earliest chapters of galaxy evolution.  

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Sources:  

1. NASA 2022. NASA’s Webb to Uncover Riches of the Early Universe, Published 22 June 2022. Available online at https://webbtelescope.org/contents/news-releases/2022/news-2022-015.html Accessed on 23 June 2022. 

2. Prasad U., 2021. James Webb Space Telescope (JWST): The First Space Observatory Dedicated to the Study of Early Universe. Scientific European. Published 6 November 2021. Available online at https://www.scientificeuropean.co.uk/sciences/space/james-webb-space-telescope-jwst-the-first-space-observatory-dedicated-to-the-study-of-early-universe/

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