Webb gives us an amazing new look in this lonely dwarf galaxy

The James Webb Space Telescope (ERS) early launch science program – first released on July 12, 2022 – has proven to be a treasure trove of scientific discoveries and breakthroughs.

Among the many areas of research it allows is the study of the Resolved Stellar Populations (RSTs), which has been the subject of ERS 1334.

This refers to large groups of stars close enough that individual stars can be distinguished but far enough apart that telescopes can capture many of them simultaneously. A good example is the Wolf-Lundmark-Melot dwarf (WLM) galaxy that neighbors the Milky Way.

Kristen McQueen, associate professor of astrophysics at Rutgers University, is one of the principal scientists in the Webb ERS program whose work focuses on RSTs. I recently spoke to Natasha Biro, NASA’s Senior Communications Specialist, about how JWST has enabled new studies on WLM.

Enhanced Webb’s observations revealed that this galaxy has not interacted with other galaxies in the past.

According to McQueen, this makes it a great candidate for astronomers to test theories of the formation and evolution of galaxies. Below are highlights of that interview.

About WLM

WLM is located about 3 million light-years from Earth, which means that it is fairly close (astronomically speaking) to the Milky Way. However, it is also relatively isolated, leading astronomers to conclude that it did not interact with other systems in the past.

When astronomers observed other dwarf galaxies nearby, they noticed that they were usually entangled with the Milky Way, indicating that they were in the process of merging.

This makes studying them more difficult since their populations of stars and gas clouds are completely indistinguishable from our group.

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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 populated stars and dispersed when these stars exploded in supernovae.

In the case of WLM, which has seen star formation throughout its history, the force of these explosions has pushed these elements outward over time. This process is known as “galactic winds” and has been observed in small, low-mass galaxies.

JWST Pictures

Webb’s new images provide the clearest view of WLM ever. Previously, the dwarf galaxy was imaged by the Infrared Array Camera (IAC) on 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).

Part of the dwarf galaxy Wolf-Lundmark-Melotte (WLM) was captured by the Spitzer Space Telescope’s Infrared Array camera (left) and the James Webb Space Telescope’s near-infrared camera (right). (NASA, ESA, CSA, IPAC, Kristen McQuinn (RU) / Zolt G. Levay (STScI), Alyssa Pagan (STScI))

As you can see, Webb’s infrared optics and advanced instrument cluster provide a much deeper view that allows distinguishing stars and individual features. As McQueen described it:

“We can see countless individual stars of different colours, sizes, temperatures, ages, and stages of evolution; interesting clouds of nebulous gas within the galaxy; foreground stars with Webb diffraction heights; and background galaxies with elegant features like tidal tails. It really is a fascinating picture. “.

ERS . program

As McQuinn explained, the main scientific focus of ERS 1334 is to build on previous experience developed using Spitzer, Hubble, and other space telescopes to learn more about the history of star formation in galaxies.

Specifically, they are performing deep, multi-band imaging of three star systems resolved within Megaparsec (about 3,260 light-years away) from Earth using the Webb’s Near-Infrared Camera (NIRCam) and the Non-Split Imaging Near-Infrared Spectrograph (NIRISS).

These include the globular cluster M92, the extremely faint dwarf galaxy Draco 2, and the star-forming dwarf galaxy WLM.

The number of low-mass stars in WLM makes it particularly interesting because it is long-lived, which means that some of the stars seen there today may have formed during the early universe.

“By characterizing these low-mass stars (such as their ages), we can gain insight into what was going on in the very distant past,” McQueen said.

“It’s very complementary to what we’ve learned about the early formation of galaxies by looking at high redshift systems, where we see galaxies as they were when they first formed.”

Another goal is to use the WLM dwarf galaxy to calibrate the JWST to ensure it can measure the brightness of stars with pinpoint accuracy, which will allow astronomers to test models of stellar evolution in the near infrared.

McQuinn and her colleagues are also developing and testing proprietary software to measure the brightness of stars imaged with NIRCam, which will be made available to the public.

The results of their ESR project will be released prior to the second cycle call for proposals (January 27, 2023).

The James Webb Space Telescope has been in space for less than a year but has already proven invaluable. The stunning views of the universe that I provided include deep field images, extremely accurate observations of galaxies and nebulae, and detailed spectra of the atmospheres of exoplanets.

The scientific discoveries it actually allowed were nothing short of groundbreaking. Before its planned 10-year mission expires (which can be extended to 20 years), some real breakthroughs in the paradigm change are expected.

This article was originally published by Universe Today. Read the original article.

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