Becky Ferreira
WALL – The universe we live in is interconnected by the ‘cosmic web’, a vast network of filaments (filamentous structure) made up of gas and dark matter, a mysterious substance that has yet to be explained, while it spans billions of light years.
Now, scientists have detected galaxies aligned along these filaments in never-before-seen patterns; The new research, published today, is an exploration that sheds light on the evolution of galaxies within the large-scale architectural structure of the cosmos. The research adds to a growing body of evidence that demonstrates the impact of the cosmic web on the evolution of galaxies in space-time.
THE SPIDERNET OF THE UNIVERSE
Researchers led by Stefania Barsanti, an astronomer at the Australian National University, studied hundreds of galaxies observed within the SAMI Galaxy Survey conducted at the Siding Spring Observatory in Australia. As reported in a new study published in the Monthly Journal of the Royal Astronomical Society, the team has investigated “galaxy formation”, which includes “halo” structures from which galaxies form, where the mass of a galaxy’s central bulge (a balloon-like spherical structure) is related to its orientation in the cosmic web. announced the discovery of a “memory”.
“How galaxies acquire their angular momentum in the cosmic web is of great importance in understanding galaxy formation and evolution,” Barsanti and colleagues say in their paper. It is expected to be influenced by the halos of its possessor and its current position and past in the evolving cosmic web.”
Previous research has shown that a galaxy’s location in the cosmic web has effects on its chemical content, and that galaxies can be used to track the rotation of cosmic filaments, among many other mind-blowing discoveries.
INVISIBLE FACTOR AFFECTING FORMATION
Meanwhile, Barsanti and his colleagues studied a possible relationship between the mass of a galaxy’s central bulge and its alignment with the filament. Their simulations reveal that galaxies with larger projections tend to spin on axes perpendicular to the filament in which they are embedded, while galaxies with smaller projections spin parallel to the grid, although until now no one has noticed this trend in real space.
“An intriguing question that arises is whether we can detect a correlation between the properties of the protrusions and the spin–filament alignment trends in the observations,” the researchers write in their paper.
“We leverage the SAMI Galaxy Survey to define the spin axes of galaxies, ridges and disks, and the spectroscopic studies of the deep and highly complete (Galaxy and Mass Unification) GAMA survey to reconstruct the cosmic web,” they continue. It will help shed light on the formation mechanisms of discs.”
The observations were in line with the simulations, revealing that galaxies with a large bulge tend to rotate on a perpendicular axis compared to the cosmic filament, while galaxies with smaller projections rotate parallel to the grid. This pattern can be attributed to the different ways galaxies can form. Low-mass galaxies are basically agglomerated from gas flowing through the filament; therefore they are aligned with the larger cosmic structure. In contrast, high-mass galaxies are most likely the products of collisions between galaxies that show a steep orientation in the process of merging.
MORE RESEARCH IS NEEDED
“We discovered an observational link between galaxy spin–filament alignments and bulge growth,” the team says in their paper. “This connection can be explained by mergers that can cause rotation and bulge formation, as seen in galaxy formation simulations.”
The research offers another striking look at the connection that exists between the cosmic web and the galaxies entangled in it. Details like these can be very difficult to detect in an observational context; however, integral-field spectroscopy (IFS) projects such as the SAMI Galaxy Survey are increasingly revealing these details. Accordingly, Barsanti’s team looks forward to next-generation IFS studies such as the Hector Galaxy Survey, which will be able to observe tens of thousands of galaxies.
“Additional clues to processes associated with shifting spin alignment to the nearest cosmic filament can be discovered by examining individual spin–filament alignments of galaxy components, such as protrusions and disks,” Barsanti and colleagues say.
They conclude, “Although they provide a consistent view that is in line with simulations, due to the relatively small number of galaxies used in the analyzes and the poor statistical significance of the results, for now we can only reach thought-provoking clues in the context of galaxy formation scenarios.” “It will be able to draw stronger conclusions from spin–filament alignments regarding the physical mechanisms that lead to the formation of protrusions and disks, as well as limiting the roles of local and global environments in determining galaxy spins.”
Original article vice.com taken from the website. (Translated by Tarkan Tufan)