A research team led by astronomers at Rutgers University in New Brunswick is using massive amounts of data collected by NASA’s James Webb Space Telescope to search for clues about the conditions that existed in the early universe. The research team cataloged the ages of stars in the Wolf-Landmark-Mellott Galaxy (WLM). The WLM, next to the Milky Way, is an active star-forming center containing ancient stars that formed 13 billion years ago. “By looking this deep and seeing so clearly, we are essentially going back in time,” said Kristen McQuinn, who led the study published in the Astrophysical Journal. Ta. “Essentially, you’re doing a kind of archaeological excavation to find very low-mass stars that formed early in the history of the universe.” McQueen credits his team with being able to calculate the galaxy’s stellar history thanks to his high-performance Amarel cluster operated by Rutgers’ Advanced Research Computing Directorate. One aspect of the research involved repeating a large calculation 600 times, McQueen said. Of particular interest to McQueen are the low-mass galaxies that dominated the early Universe. These allow researchers to study star formation, the evolution of chemical elements, and the effects of star formation on the gas and structure of galaxies. WLM is an irregular galaxy. There is no clear shape. The galaxy was discovered in 1909 by German astronomer Max Wolff and further characterized in 1926 by Swedish astronomer Knut Landmark and British astronomer Philibert Jacques Mellot. WLM is located at the edge of a local group that includes the Milky Way. Mackin discovered that this location at the edge of the Local Cluster protects his WLM from the harmful effects of mixing with other galaxies, leaving its stellar population in a pristine state. WLMs are also of interest to astronomers because they are dynamic, complex systems containing large amounts of gas that can actively form stars. To study the star formation history of galaxies, McQueen and her team used telescopes to carefully identify regions of the sky containing hundreds of thousands of individual stars. To determine a star’s age, scientists measured its color and brightness, which are indicators of its temperature. By cataloging stars in this way, the researchers showed that WLM’s ability to produce stars is decreasing over time. The team’s observations confirm scientists’ previous estimates that galaxies have been producing stars for 3 billion years, early in the universe’s history. It stopped for a while, then flared up again. McQueen said he believed the outage was caused by conditions common in the early universe. “It was really hot in space at that time,” she said. “We believe that the temperature of the universe eventually warmed the gas in this galaxy and star formation stopped for a while. The cooling phase lasted billions of years, and then star formation started again.” The research is part of NASA’s Early Release Program, in which scientists work with the Space Telescope Science Institute to conduct research that highlights Webb’s capabilities and helps astronomers prepare for future observations.

source: https://iopscience.iop.org/article/10.3847/1538-4357/ad1105