Researchers from Columbia University, utilizing imagery from NASA’s James Webb Space Telescope, have unveiled a striking revelation about galaxies in the early universe. Contrary to the predominantly spherical shape resembling balls of pizza dough found in the present-day universe, a significant portion—approximately 50 to 80%—of the studied galaxies display a distinct flat and elongated profile, reminiscent of breadsticks.
Viraj Pandya, the lead author of the research paper soon to be featured in The Astrophysical Journal (currently available on the arXiv preprint server), sheds light on this unexpected observation. According to Pandya, the prevalence of galaxies with a morphology resembling long, thin breadsticks during the early universe is noteworthy, particularly since such a configuration is uncommon among galaxies in the contemporary universe.
The research team delved into an extensive collection of near-infrared images from the James Webb Space Telescope, specifically the Cosmic Evolution Early Release Science (CEERS) Survey. Their focus was on identifying galaxies believed to have existed during a timeframe spanning 600 million to 6 billion years ago.
In this cosmic survey, the majority of distant galaxies exhibited a breadstick-like elongation. However, a diverse range of shapes emerged, including pizza pie and sphere-like configurations. Interestingly, the “balls of pizza dough,” representing sphere-shaped galaxies, were noted as the smallest type of galaxies and were relatively less prevalent. On the other hand, pizza pie-shaped galaxies, comparable in size to their breadstick-shaped counterparts along their longest axis, were more abundant. Notably, these pizza pie-shaped galaxies were found to be more common in the nearby universe, characterized by older and more mature galaxies, attributed to the ongoing expansion of the universe.
If we could rewind the cosmic clock by billions of years, our Milky Way galaxy might have fallen into the category of a breadstick-shaped galaxy, according to Haowen Zhang, a Ph.D. candidate at the University of Arizona in Tucson and co-author of the study. This speculation is supported by recent evidence gathered from the James Webb Space Telescope (Webb). Theorists have extrapolated the past mass of the Milky Way billions of years ago, indicating a probable breadstick shape during that distant era.
These early galaxies, including the hypothesized early Milky Way, differ significantly from the more massive nearby spirals and ellipticals. They serve as precursors to the formation of larger galaxies like our own. As Kartheik Iyer, a co-author and NASA Hubble Fellow at Columbia University, points out, in the early universe, galaxies had comparatively less time to grow.
The identification of additional categories for early galaxies is seen as an exciting development by the researchers. This expanded understanding provides a rich field for further analysis, allowing for a deeper exploration of the relationship between galaxies’ shapes, their appearances, and offering improved insights into the detailed processes governing their formation.
The Hubble Space Telescope, operational since 1990 and continuously collecting data, has long revealed a prevalence of elongated galaxies, as noted by co-author Marc Huertas-Company, a faculty research scientist at the Institute of Astrophysics on the Canary Islands. The lingering question for researchers was whether the sensitivity to infrared light of the James Webb Space Telescope (Webb), launched in 2021, could unveil additional details in these galaxies.
According to Huertas-Company, Webb’s observations confirmed that Hubble did not overlook any additional features in the galaxies they both studied. Furthermore, Webb provided a more comprehensive view by revealing numerous distant galaxies with similar flattened and elongated shapes, presenting these features in intricate detail.
The researchers are now intrigued by the question of why early galaxies exhibited this distinctive flattened and elongated morphology. One hypothesis, as explained by Pandya, is rooted in the idea that the early universe may have been traversed by filaments of dark matter forming a kind of “skeletal background” or “cosmic highway.” These filaments could have served as conduits guiding gas and stars along their paths. Although these filaments still exist, they have become more diffuse as the universe expanded, potentially reducing their influence on the formation of breadstick-shaped galaxies.
Titled “Galaxies Going Bananas,” the paper takes on yet another food analogy that naturally emerged during the authors’ examination of their data. The term “bananas” was adopted when the researchers plotted the aspect ratios of galaxies against their longest axis length. This graphical representation strikingly resembled bananas, symbolizing the prevalent elongated ellipsoid (breadstick-shaped) configuration of these galaxies.
Viraj Pandya notes that the term “bananas” encapsulates the idea that these inherently elongated galaxies appear to be the dominant ones during the initial 4 billion years of the universe’s existence.
Despite these intriguing findings, there are knowledge gaps that need addressing. To refine our understanding of the properties and specific locations of distant galaxies, researchers require a more extensive dataset from the James Webb Space Telescope. Additionally, refining and updating models is essential to better capture the precise geometries of these remote galaxies.
As emphasized by co-author Elizabeth McGrath, an associate professor at Colby College in Waterville, Maine, these are early results, and further in-depth analysis is necessary to unravel the underlying dynamics. The researchers express enthusiasm about the initial trends but acknowledge the need for deeper exploration into the data to uncover the intricacies of these distant galactic formations.
Resources
- ONLINE NEWS Columbia University. (2024, January 17). Webb data suggest many early galaxies were long and thin, not disk-like or spherical. Phys.org. [Phys.org]
- JOURNAL Pandya, V., Zhang, H., Huertas-Company, M., Iyer, K. G., McGrath, E. J., Barro, G., Finkelstein, S. L., Kuemmel, M., Hartley, W. G., Ferguson, H. C., Kartaltepe, J. S., Primack, J. R., Dekel, A., Faber, S. M., Koo, D. C., Bryan, G. L., Somerville, R. S., Amorín, R., Haro, P. A., . . . Yung, L. Y. A. (2023). Galaxies Going Bananas: Inferring the 3D Geometry of High-Redshift Galaxies with JWST-CEERS. arXiv (Cornell University). [arXiv.org]
Cite this page:
APA 7: TWs Editor. (2024, January 18). Insights from Webb Data: Early Galaxies Displayed Elongated Shapes Rather Than Disk-Like or Spherical Structures. PerEXP Teamworks. [News Link]
