James Webb Space Telescope Early Release Science (ERS) program – first announced on 12 July 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 (RSTs), which were the subject of ERS 1334.
This refers to large groups of stars close enough that individual stars can be detected, but telescopes can capture many of them at once. A good example is Wolff-Lundmark-Melot (WLM) dwarf galaxies that are neighbors of the Milky Way.
Kristen McQueen, an assistant professor of astrophysics at Rutgers University, is a principal scientist in the Webb ERS program whose work focuses on RST. recently, He spoke with Natasha PirroNASA Senior Communications Specialist, on how JWST enabled WLM’s new research.
Webb’s advanced observations revealed that this galaxy has not interacted with other galaxies in the past.
According to McQueen, this makes it an excellent candidate for astronomers to test theories of galaxy formation and evolution. Here are the highlights of that interview.
The WLM is about 3 million light-years from Earth, which means it’s fairly close (in astronomical terms) to the Milky Way. However, it is relatively isolated, leading astronomers to conclude that it has not interacted with other systems in the past.
When astronomers observed other nearby dwarf galaxies, they noticed that they were usually intertwined with the Milky Way, indicating that they were in the process of merging.
This makes them difficult to study because their stellar and gas cloud populations are indistinguishable from our own.
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Another important point about the WLM is that it is low in heavy elements compared to hydrogen and helium (which were very common 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 the WLM, which has experienced star formation throughout its history, the energy of these explosions pushed these elements out over time. This process is known as the “galactic wind” and has been observed with small, low-mass galaxies.
The new Webb images provide the clearest view of the WLM ever seen Previously, dwarf galaxies were depicted Infrared array camera (IAC) ON Spitzer Space Telescope (SST).
These provide limited resolution compared to web images, as seen in the side-by-side comparison (shown below).
As you can see, Webb’s advanced suite of infrared optics and instruments provides a much deeper view that allows individual stars and features to be distinguished. As McQueen describes:
“We see countless individual stars of different colors, sizes, temperatures, ages, and evolutionary stages; interesting clouds of nebular gas within the galaxy; foreground stars with web dispersion spikes; and background galaxies with neat features like tidal tails. It’s a really beautiful picture.”
As McQueen explained, the main science focus of ERS 1334 is to learn more about the galaxy’s star formation history, building on previous expertise made with Spitzer, Hubble and other space telescopes.
Specifically, they are conducting deep multi-band imaging of three resolved stellar systems within one megaparsec (~3,260 light-years) of Earth using WEB. Near the infrared camera (NIRCam) and Near-infrared imaging slitless spectrograph (Niris).
These include globular clusters M92Very faint dwarf galaxies Drake 2and star-forming WLM dwarf galaxies.
The population of low-mass stars in the WLM makes it particularly interesting because they are so long-lived, which means that some of the stars seen there today may have formed early in the Universe.
“By determining the properties of these low-mass stars (like their ages), we can gain insight into what was happening in the very distant past,” said McQueen.
“Looking at this is very complementary to what we learn about the early formation of galaxies High-redshift systemswhere we see galaxies as they existed when they first formed.”
Another objective is to use the WLM dwarf galaxy to calibrate JWST so that it can measure stellar brightness with extreme precision, allowing astronomers to test stellar evolution models in the near-infrared.
McQueen and his colleagues are developing and testing non-proprietary software to measure the brightness of resolved stars imaged with NIRCam, which will be made available to the public.
Their ESR project results will be published before the Cycle 2 Call for Proposals (27 January 2023).
The James Webb Space Telescope has been in space for less than a year but has already proven itself invaluable. The breathtaking views of the universe it provides include deep-field images, highly precise observations of galaxies and nebulae, and detailed spectra from the atmospheres of exoplanets.
The scientific advances it has already allowed are nothing short of groundbreaking. Before the end of its planned 10-year mission (which could be extended to 20), some truly paradigm-shifting breakthroughs are expected.
This article was originally published by Universe Today. After this Main article.
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