The Formation of the First Galaxies and Reionization with the James Webb Space Telescope

Project Information

EPOCHS

Grant agreement ID: 788113

DOI

10.3030/788113

EC signature date 25 May 2018

Start date 1 May 2020

End date 30 April 2027

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 951 138,00

EU contribution

€ 1 951 138,00

Coordinated by

THE UNIVERSITY OF MANCHESTER
United Kingdom

Periodic Reporting for period 3 - EPOCHS (The Formation of the First Galaxies and Reionization with the James Webb Space Telescope)

Reporting period: 2022-02-01 to 2023-10-31

Summary of the context and overall objectives of the project

EPOCHS - Probing Early Galaxy Formation with the James Webb Space Telescope

This report details the progress made on my ERC research project probing early galaxy formation with the James Webb Space Telescope, also known as EPOCHS. Our research on these early galaxies is nearly completely funded by the European Research Council (ERC), and aims to study the early onset of galaxy formation and how galaxies change over the first few billion years of the universe using the new capabilities of the James Webb Space Telescope (JWST).

The James Webb Space Telescope (JWST) has several key advantages over previous telescopes when it comes to studying early galaxy formation. Below we list some of the major problems related to early galaxy formation that JWST can help to solve and for which we are addressing in EPOCHS, funded by the ERC. This ERC funding is essential as this work needs significant post-doc support to be carried out effectively.

One of the big questions we are addressing is the detection of very distant galaxies, including the very first galaxies to form. One of the primary challenges in studying early galaxy formation is that the galaxies are very distant and therefore difficult to detect, and even the most powerful telescopes before JWST could not probe the earliest galaxies. Because JWST has a larger mirror than previous space telescopes it is much more sensitive than anything before it, including the Hubble Space Telescope, allowing it to detect galaxies that are further away and more distant in time than anything seen before. The issue is that this has to be done carefully as contamination from closer galaxies is significant and removing these can take a significant amount of time and effort. By finding these galaxies we can then determine how many there are and compare this to models of galaxy formation, which have firm predictions on the number of galaxies that should exist as a function of time.

Another goal is imaging galaxies in their formative stages, and finding how their structure and morphologies and other properties evolved with time. One major challenge in studying early galaxy formation is that the galaxies are still in their formative stages, making them difficult to study as they are not only distant, but much smaller than galaxies today, as galaxies have grown with time. JWST's infrared capabilities using different camera, including NIRCam - the most advanced NIR imager space - allow us to see through the dust and gas that often obscures galaxies in their early stages of formation, enabling us to study them in great detail and thus derive how their properties have changed with time. One of these properties is the size evolution of galaxies which must be measured very carefully and gives us some ideas about the physics behind galaxy assembly.

We are want to measure the physical properties of early galaxies. Our goal is to measure properties accurately which will greatly aid our understanding of the physical properties of early galaxies, such as their mass, size, and chemical composition. All of these are important quantities for understanding how galaxies form and evolve over time. JWST's spectroscopic capabilities will allow us to measure these properties more accurately and with greater precision than previous telescopes. We have started to measure these features with the NIRSpec instrument on JWST and are goal is to combine imaging and spectroscopy from JWST to decipher how galaxy formation progressed and continued over the first few billion years. By carrying out this research project we will find how galaxy formation occurred in the early universe, the primary goal of EPOCHS.

Overall, studying distant galaxies with the James Webb Space Telescope has the potential to expand our understanding of the universe and our place in it, which will help us understand our ultimate origins. This work will also inspire the next generation of scientists, improve our understanding of galaxies which will help in other areas of astrophysics. Innovations in machine learning and software will potentially have other technical benefits for society.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Over the course of the ERC grant period since 2021, we have made significant progress towards achieving our research goals. We have developed and tested new data analysis techniques to extract information concerning the detection and properties of high redshift galaxies from JWST observations using both the NIRCam and NIRSpec instruments. Our group, in collaboration with others, have carried out simulations to predict what we might expect to observe with JWST and how to test various ideas about early galaxy formation from comparing model outputs with the observations. This is leading to us discovering the physical mechanisms behind the assembly of galaxies.

The work performed by us includes acquiring the JWST data and downloading it onto our computers at Manchester University. Once the data was obtained, our ERC funded team reduced it to remove noise, bad pixels, and other artefacts, and then analysed it using new techniques developed specifically for this project. We then searched the images for distant galaxies and made catalogs and then studied the properties of these galaxies, resulting in a few papers already and more to be submitted shortly. We find many new distant galaxies that were previously unknown and have measured their properties. We also found that many of these systems are disk like in structure which was a major surprise and discovery.

These efforts are now allowing us to understand the underlying physical mechanisms that govern the assembly of galaxies for the first time.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Overall, we are pleased with the progress we have made on the EPOCHS project, thanks to the support of the ERC. We have made several discoveries about the early universe, including a new population of distant galaxies that were unknown to astronomers and also uncovering the true morphologies of distant galaxies. We have shown that disk galaxies are the dominant morphological type for galaxies in the early universe, whereas before in the state of the art, these were thought to be mergers.


We are looking forward to continuing our research with the JWST and contributing to our understanding of the early universe. One of the things we will do is search for galaxies with the first stellar populations within them. This will give us some idea of the onset of the first generations of stars and in what conditions they form in. This is completely unknown at present.