The first deep-field image of space taken by the James Webb Space Telescope (JWST) allowed scientists to study the faint, almost ghostly light from orphan stars that exist between galaxies in galactic clusters.
These stars, not gravitationally bound to galaxies, are pulled from their homes by the massive tidal forces between galaxies and drifted into intergalactic space. The light emitted by these star orphans is called intracluster light, and it is so faint that it has only one percent of the brightness of the darkest visible sky. Placeπ§π·
Studying this ghostly light from orphan stars can not only reveal how galaxy clusters form, but also give scientists clues about the properties of stars. dark mattera mysterious substance that makes up about 85% of the mass of the universe.
Related: James Webb Space Telescope reveals the universe’s earliest galaxies like never before
Dark matter doesn’t interact with light, which means scientists know it’s not the same as everyday matter. protons and neutronsπ§π· Its existence can currently only be determined by the gravitational force that prevents the separation of stars and planets of galaxies.
JWST sees the universe in infrared light, frequencies of electromagnetic radiation that allow astronomers to see galaxy clusters differently than they do in visible light.
The sharpness of the JWST infrared images allowed Instituto de AstrofΓsica de Canarias (IAC) researchers Mireia Montes and Ignacio Trujillo to study the intracluster light from the galaxy cluster SMACS-J0723.3β7327 in an unprecedented level of detail.
This sharpness comes from the fact that JWST images of SMACS-J0723.3β7327, about 4 billion light-years away in the constellation Volans, are twice as deep as previous observations of the same cluster. Hubble Space Telescopeπ§π·
“In this study, we show the great potential of JWST to observe a very faint object,” said Montes, first author of the study. statement (opens in new tab)π§π· “This will allow us to study very distant galaxy groups and in more detail.”
Studying this faint intracluster light required more than just JWST’s observational power, but it meant the team also had to develop new image analysis techniques. “In this work, we had to do additional processing on the JWST images so that we could study the intracluster light, because it is a faint and extended structure,” explained Montes. “This was key to avoiding biases in our measurements.”
The scientists’ findings are a striking demonstration of the potential of intracluster light to reveal the processes behind structure formation in galaxy clusters.
“Analyzing this diffuse light, we see that the inner parts of the cluster are formed by mergers of large galaxies, and the outer parts are formed by the accumulation of galaxies similar to our own. Milky Way” said Montes.
Furthermore, because stars within a cluster follow the gravitational influence of the cluster as a whole, rather than of individual galaxies, the light from these stellar orphans provides an excellent way to study the distribution of dark matter in these clusters.
“JWST will allow us to characterize the distribution of dark matter in these massive structures with unprecedented precision and shed light on its fundamental nature,” added Trujillo, the study’s second author.
The duo’s research was published in December. in 1 Astrophysical Journal Letters (opens in new tab)π§π·
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