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.
