We are thrilled to share the science of the James Webb Telescope (JWST) and how UCI scientists are involved in using this incredible tool for their work. The JWST is a successor of the Hubble telescope and is one of the finest telescopes humanity has ever built, with the most giant mirror for any space telescope. It is placed 1.5 million km from the earth at a point called the Lagrange 2 to protect it from the sun’s direct heat. Its mission is to look for the farthest lights in the universe, observe the Big Bang’s afterglow, study the oldest stars and remnants, and explore strange new worlds in our galaxy and beyond.
Deep Dive into JWST
The James Webb Space Telescope (JWST) recently unveiled its first images. These images represent the deepest observations of the distant universe, capturing light beyond the range of human vision. Typically when we look at beautiful images of the universe like these, we see light from the visible or optical part of the spectrum. The JWST is an infrared telescope with a 6.5 meter (21 feet!) diameter primary mirror. Mirrors that large are incredibly hard to make and even harder to send out to space, so the mirror is made of 18 smaller segments that unfold and adjust their position to create the 6.5-meter diameter mirror. (1). JWST will look at wavelengths of light in the infrared spectrum, from 0.6 microns to 28.3 microns (2). These are similar wavelengths that are seen with night vision goggles and that your remote control uses to communicate with your TV and are longer than the visible wavelengths.
To illustrate the power of JWST, above we show a small part of the large Magellanic cloud for SPITZER and compare it with JWST.
Image credit: NASA/JPL-Caltech (left), NASA/ESA/CSA/STScI (right)
Useful Astronomical Concept: Redshift
Redshift (z) is a way for astronomers to measure the distance between us and a galaxy through what is known as the Doppler effect. Imagine an ambulance siren approaching you; as it does its pitch increases, and as it moves away its pitch decreases. Similarly, as astronomical objects are redshifted, they are moving farther away from us, and as they are blue-shifted, they are moving toward us. The faster they move, and thus the higher their redshift, the farther away they are.
UCI Involvement in Cycle 1
Dr. Aaron Barth’s Quest for Quasars
Professor Aaron Barth will use JWST to study quasars, which are among the most energetic objects in the Universe. These objects are powered by supermassive black holes (SMBH). He plans to observe targets at high redshifts, meaning they are extremely far away. One of their team’s goals for the high-z quasar observations with JWST will be to search for evidence of outflows in the ionized gas surrounding the quasar. This can be done using a technique called integral-field spectroscopy, which maps the motion of matter around the quasars. At very high luminosities, quasars are expected to drive powerful winds or outflows that force gas away from the quasar and into the surrounding circumgalactic environment. Barth and his team will look for direct evidence of these outflows and measure their energetics. With JWST, for the first time, it will be possible to carry these measurements to the highest observed redshifts of known quasars (up to z=7.6). A second goal for Dr. Barth and his team is to get better constraints on the mass of the black holes. With JWST’s capabilities, these projects will aid our understanding of quasar environments and their relation to the evolution of black holes at high redshifts.
Image credit: International Gemini Observatory/NOIRLab/NSF/AURA/P. Marenfeld.
Dr. Vivian U’s exploration for Merging Galaxies
Dr. Vivian U will be using JWST to study the effect of galaxy mergers on Active Galactic Nuclei (AGN), which are powered by the active accretion of matter onto the SMBH at the center of galaxies. When two or more galaxies merge and interact they can initiate intense bursts of star formation and SMBH growth. Dr. U and the team will explore how this gas feeds into SMBH growth and determine if BHs merge too. To explore this, their team will study galaxies at low redshift because resolving the features at these spatial scales is easier. In particular, they will be looking at 4 objects which include Markarian 273 and UGC 5101. With JWST, their team can explore galaxy mergers which can tell us more about galaxy evolution.
UGC 5101 Markarian 273
Image credit:NASA/ESA
Dr. Marina Bianchin Maps Gaseous Disks Around SMBHs
Dr. Marina Bianchin is involved in three different projects designed to study the connection between SMBHs at the centers of galaxies and the interstellar medium around them, specifically looking at how this exchange impacts galaxy evolution. Each project uses integral field unit (IFU) observations of the central regions of galaxies. These types of observations allow Dr. Bianchin to have information about the gas at different locations around the SMBH, like a 2D map of the gaseous disk. To obtain a more detailed understanding of these gaseous disks, Dr. Bianchin studies SMBHs that are nearby, with one project looking at z < 0.05 and another at z ~ 2. She is looking at primarily molecular gas, mainly molecular hydrogen (H2). Molecular hydrogen is important because it is the most abundant molecule in the universe and is the fuel used for star formation. With JWST, for the first time, astronomers like Dr. Bianchin can observe H2 around SMBHs to see if the H2 gas is perturbed, severely impacting star formation, or if H2 gas can survive the extreme radiation of quasars.
IFU stamp for nearby galaxy NGC7469
Image credit: Bianchin et al. 2023, Figure 1
Corey Beard’s search for signs of life
Hypothetically, if UCI graduate student Corey Beard were awarded time on JWST, he would use it to explore the atmosphere of a hot exoplanet named TOI-2136b. This planet is a mini-Neptune, which is 2-4 times as massive as Earth and has H-He atmospheres, and it has a 7.8-day orbit around its stars. On our planet, nitrogen-fixing bacteria take Hydrogen and Nitrogen from the atmosphere to form ammonia (NH3). Corey would like to look for signs of NH3 on TOI-2136b with JWST, and its presence would strongly indicate the presence of microbes on that planet!
Image Credit: NASA/JPL-Caltech/R. Hurt (SSC)
In addition to these teams, Dr. Mike Cooper and Dr. Steph Sallum’s teams are also involved with the JWST mission. In particular, Dr. Cooper is working with the Cosmic Evolution Early Release Science Survey (CEERS) team to find the furthest galaxies ever discovered. Meanwhile, Professor Sallum will use JWST to explore planet formation with the direct imaging technique. We are thrilled to see all the results these teams will acquire in the upcoming years and how it will advance our understanding of the universe.
1. https://www.jwst.nasa.gov/content/about/index.html
2. https://www.jwst.nasa.gov/content/about/faqs/facts.html
Cover Image Credit: NASA
Authors: Vidya Venkatesan and Stephanie Stawinski
Edited by Dylan Green