The James Webb Space Telescope Early Exit Science (ERS), first launched on July 12, 2022, has proven to be a treasure trove of scientific discoveries and breakthroughs.
Among the many areas of research it is enabling is the study of Resolved Stellar Populations (RST), which was the subject of ERS 1334.
This refers to large groups of stars close enough that individual stars can be distinguished but far enough away that telescopes can capture many of them at once. A good example is the Wolf-Lundmark-Melotte (WLM) neighboring dwarf galaxy of the Milky Way.
Kristen McQuinn, an assistant professor of astrophysics at Rutgers University, is one of the lead scientists for the Webb ERS program, whose work focuses on RSTs. Recently, spoke with Natasha PiroNASA Senior Communications Specialist, on how the JWST has enabled new studies of the WLM.
Webb’s enhanced observations have revealed that this galaxy has not interacted with other galaxies in the past.
According to McQuinn, this makes it a great candidate for astronomers to test theories of galaxy formation and evolution. Here are the highlights of that interview.
Regarding WLM
The WLM is approximately 3 million light-years from Earth, which means that it is quite close (in astronomical terms) to the Milky Way. However, it is also relatively isolated, leading astronomers to conclude that it has not interacted with other systems in the past.
When astronomers looked at other nearby dwarf galaxies, they noticed that they are normally entangled with the Milky Way, indicating that they are in the process of merging.
This makes them more difficult to study since their population of stars and gas clouds is completely indistinguishable from our own.
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Another important thing about WLM is that it is low in terms of elements heavier than hydrogen and helium (which were very prevalent in the early Universe). Elements such as carbon, oxygen, silicon, and iron formed in the cores of early population stars and were dispersed when these stars exploded in supernovae.
In the case of WLM, which has undergone star formation throughout its history, the force of these explosions has ejected these elements over time. This process is known as “galactic winds” and has been observed with small, low-mass galaxies.
JWST Images
Webb’s new images provide the clearest view of WLM ever seen. Previously, the dwarf galaxy was photographed by the infrared array camera (IAC) in the Spitzer Space Telescope (SST).
These provided limited resolution compared to Webb’s images, which can be seen in the side-by-side comparison (shown below).
As you can see, Webb’s infrared optics and advanced suite of instruments provide a much deeper view that allows individual stars and features to be differentiated. As McQuinn described it:
“We can see a myriad of individual stars of different colors, sizes, temperatures, ages, and stages of evolution; interesting nebular gas clouds within the galaxy; foreground stars with Webb diffraction spikes; and background galaxies with neat features. like tidal tails. It’s really a beautiful picture.”
The ERS Program
As McQuinn explained, the main scientific focus of ERS 1334 is to build on previous experience developed with Spitzer, Hubble and other space telescopes to learn more about the history of star formation in galaxies.
Specifically, they are performing deep multiband imaging of three resolved star systems within a Megaparsec (~3260 light-years) of Earth using Webb. near infrared camera (NIRCam) and Near Infrared Imaging Slitless Spectrograph (NIRISS).
These include the global cluster M92the ultra-faint dwarf galaxy Drake IIand the star-forming dwarf galaxy WLM.
The population of low-mass stars in WLM makes it especially interesting as they are very long-lived, meaning that some of the stars seen there today may have formed during the early Universe.
“By determining the properties of these low-mass stars (such as their ages), we can gain insight into what was happening in the very distant past,” McQuinn said.
“It’s very complementary to what we learn about early galaxy formation by looking at high redshift systemswhere we see galaxies as they existed when they first formed.”
Another goal is to use the dwarf galaxy WLM to calibrate the JWST and ensure that it can measure the brightness of stars with extreme precision, which will allow astronomers to test models of stellar evolution in the near infrared.
McQuinn and his colleagues are also developing and testing non-proprietary software to measure the brightness of resolved stars imaged with NIRCam, which will be made available to the public.
The results of your ESR project will be published before the call for proposals for cycle 2 (27 January 2023).
The James Webb Space Telescope has been in space for less than a year, but has already proven invaluable. The impressive views of the cosmos he has provided include deep-field images, extremely precise observations of galaxies and nebulae, and detailed spectra of extrasolar planet atmospheres.
The scientific advances it has already enabled have been nothing short of groundbreaking. Before its planned 10-year mission (which could stretch to 20) ends, some truly paradigm-shifting breakthroughs are anticipated.
This article was originally published by universe today. Read the Original article.
