The first deep-field image of the cosmos taken by the James Webb Space Telescope (JWST) has allowed scientists to study the dim, almost ghostly light of orphan stars that exist between galaxies in galaxy clusters.
Not being gravitationally bound to galaxies, these stars are released from their homes and drifted into intergalactic space by the enormous tidal forces generated between galaxies in clusters. The light emitted by these stellar orphans is called intracluster light, and it is so dim that it has only one percent of the brightness of the darkest sky that it is possible to see. Land.
Studying this ghostly light from orphan stars could not only reveal how galaxy clusters form, but could give scientists clues about the properties of dark matterthe mysterious substance that makes up about 85% of the mass of the universe.
Dark matter doesn’t interact with light, which means scientists know it’s not the same as everyday matter made up of protons Y neutrons. Currently, their presence can only be inferred from their gravitational interactions that literally keep stars and planets in galaxies from drifting apart.
The JWST views the universe in infrared light, frequencies of electromagnetic radiation that allow astronomers to see galaxy clusters differently than the picture painted in visible light.
The sharpness of the infrared images from the JWST allowed Instituto de Astrofísica de Canarias (IAC) researchers Mireia Montes and Ignacio Trujillo to study the intracluster light of the galaxy cluster SMACS-J0723.3–7327 with an unprecedented level of detail.
This sharpness arises from the fact that the JWST images of SMACS-J0723.3–7327, which lies about 4 billion light-years from Earth in the constellation Volans, are twice as deep as observations of the same cluster. previously taken by the hubble space telescope.
“In this study, we show the great potential of JWST to observe an object that is so faint,” first author Montes said in a statement. statement (opens in a new tab). “This will allow us to study galaxy clusters that are much further away and in much more detail.”
However, studying this dim intracluster light required more than the raw observing power of the JWST, meaning the team also needed to develop new image analysis techniques. “In this work, we needed to do additional processing of the JWST images to be able to study the intracluster light, since it is a tenuous and extended structure,” Montes explained in the statement. “That was key to avoiding bias in our measurements.”
The data obtained by the scientists is an amazing demonstration of the potential of intracluster light to reveal the processes behind the formation of structure in galaxy clusters.
“By analyzing this diffuse light, we found that the inner parts of the cluster are being formed by a merger of massive galaxies, while the outer parts are due to the accumulation of galaxies similar to our own. Milky WayMontes said.
In addition to this, because the stars within the cluster follow the gravitational influence of the cluster as a whole rather than that of individual galaxies, the light from these stellar orphans presents an excellent way to study the distribution of dark matter in these clusters. cumulus
“The JWST will allow us to characterize the distribution of dark matter in these huge structures with unprecedented precision and shed light on their basic nature,” added study second author Trujillo.
The duo’s research was published on December 2. 1 in the Astrophysical Journal Letters (opens in a new tab).
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