The mysterious light within the cluster detected by astronomers


An international team of astronomers has used a new technique to describe stars in “light within a cluster,” or the faint light found between galaxies.

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We know almost nothing about the light within the group. The brightest parts of the light within the cluster are about 50 times dimmer than the darkest night sky on Earth. It is extremely difficult to detect, even with the largest telescopes on Earth – or in space.

Dr.. Cristina Martinez Lumbela is a researcher in the School of Physics at the University of New South Wales

Not only were the researchers able to detect light within the cluster, but they were also able to study and tell the history of the stars they populate with their sensitive technology, which filters out all light from objects except the light from within the cluster.

We analyzed the properties of intergalactic stars – those stray stars between galaxies. We looked at the age and abundance of the elements that make them up and then compared those features to stars that still belong to galaxy clusters. We found that the light within the cluster is smaller and less mineral-rich than the surrounding galaxiesDr. Martinez Lumbela stated.

Reconstructing the Intra-Group Light story

Not only were the orphan stars in light of the interstitial group “obsolete,” they also seemed to come from a different place than their closest neighbors. According to the researchers, the nature of the stars within the cluster is similar to the mysterious “tail” of a distant galaxy.

Researchers have been able to piece together these hints to reconstruct the history of light within the cluster and tell the tale of how its stars ended up in a stellar orphanage.

Dr.. Martinez Lumbela added,We think that these individual stars were at some points disengaged from their parent galaxies and are now floating freely, following the gravity of the group. The stripping, called tidal stripping, is caused by the passing of massive satellite galaxies – similar to the Milky Way – dragging stars in their wake.

Light within the cluster has been observed for these galaxies for the first time.

Revealing the amount and origin of light within the cluster provides a fossil record of all the interactions that a group of galaxies went through and provides a comprehensive view of the system’s interaction history.Dr. Martinez Lumbela added.

Dr.. Martinez Lumbela stated, “Also, these events happened a long time ago. galaxies [we are looking at] So far away that we are observing them as they were 2.5 billion years ago. This is the time it takes for their light to reach us.

Researchers provide important data points for the slow-burning evolution of cosmic events by observing events that occurred long ago in very distant galaxies.

Designed image processing procedures

To achieve this insightful perspective, the researchers devised an original technique.

We have developed a custom image-processing procedure that allows us to analyze the weakest structures in the universe. It follows the standard steps for studying faint structures in astronomical images – which involves 2D modeling and removing all but the light coming from the light within the cluster. This includes all the bright stars in the images, the light-blocking galaxies within the cluster and the subtraction of the constant emission from the skyDr. Martinez Lumbela added.

Dr.. Martinez Lumbela noted,What makes our method different is that it is entirely Python based, so it is very modular and can easily be applied to different sets of data from different telescopes rather than only being useful for these images. The most important finding is that when studying very faint structures around galaxies, every step in the process counts and every unwanted light must be accounted for and removed. Otherwise, your measurements will be wrong.

Dr. Martnez-Lombilla stated that the methods used in this research are experimental, which enhances future analyzes of light within the group.

Our main long-term goal is to extend these results to a large sample of galaxy clusters. Then we can look at the statistics and see the typical characteristics related to the formation and evolution of light within the cluster and these very common systems of galaxy clustersDr. Martinez Lumbela added.

Dr. Martinez Lumbela concluded, “This is essential work to prepare the next generation of deep, whole-sky surveys such as those to be conducted with the Euclid Space Telescope and the LSST with the Vera C. Rubin Observatory.

Journal reference:

Martinez Lumbela, C. et al. (2022) Galaxy and Mass Assembly (GAMA): Intra-cluster stretched light in a cluster at z = 0.2 from Hyper Suprime-Cam depth images obtained by the reach arrow. Monthly Notices of the Royal Astronomical Society. doi: 10.1093/mnras/stac3119

Source: https://www.unsw.edu.au/

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