December 10, 2023


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Webb observes the Milky Way’s twin in the early universe

Webb observes the Milky Way’s twin in the early universe

Astronomers using the James Webb Space Telescope have discovered Ceers-2112, the most distant isolated spiral galaxy observed to date. This challenges previous assumptions about galaxy evolution, shows that galaxies became organized earlier than previously thought, and may lead to changes in theoretical models of galaxy formation.

The research team, including an astronomer from the University of California, Riverside, made the discovery using James Webb Space Telescope.

Using the James Webb Space Telescope, an international team including astronomer Alexander de la Vega of the University of California, Riverside (UCR), has discovered the most distant barred spiral galaxy-like galaxy. milky way which has been observed so far.

Until now, it was thought that barred spiral galaxies such as the Milky Way could not be observed before the universe, which is estimated to be 13.8 billion years old, reaches half its current age.

Research published in the magazine nature This week, it was led by scientists at the Center for Astrobiology in Spain.

“This galaxy, called Ceres-2112, formed shortly after its appearance the great explosionsaid co-author de la Vega, a postdoctoral researcher in the Department of Physics and Astronomy. “The finding of ceers-2112 shows that galaxies in the early universe could be as ordered as the Milky Way. This is surprising because galaxies were much more chaotic in the early universe, and very few of them had structures similar to the Milky Way.”

Understanding galactic bars

Ceers-2112 has a bar in its centre. De la Vega explained that a galactic bar is a structure made of stars within galaxies. Hungarian pubs are like the bars in our daily life, like a candy bar. He said it is possible to find bars in non-spiral galaxies, but they are very rare.

“Almost all bars are found in spiral galaxies,” said de la Vega, who joined UCLA last year after earning a doctorate in astronomy from Johns Hopkins University. “The bar in CEERS-2112 suggests that galaxies have matured and become organized much faster than we previously thought, which means that some aspects of our theories about galaxy formation and evolution need to be revised.”

Spiral blocked galaxy Sears-2112

An artistic representation of the barred spiral galaxy Circe-2112, observed in the early universe. The Earth is reflected in an imaginary bubble surrounding the galaxy, indicating the relationship between the Milky Way and CEERS-2112. Credit: Luca Costantin/CAB/CSIC-INTA

Astronomers’ previous understanding of galaxy evolution was that it took several billion years for galaxies to become organized enough to develop bars.

“The discovery of Ceers-2112 shows that it could have happened in only a small fraction of that time, about a billion years or less,” de la Vega said.

According to him, galactic bars are believed to form in spiral galaxies with stars rotating in an orderly manner, as in the Milky Way.

“In such galaxies, bars can form spontaneously due to instabilities in the spiral structure or gravitational effects from a neighboring galaxy,” de la Vega said. “In the past, when the universe was very young, galaxies were unstable and chaotic. It was thought that bars could not form or last for long in galaxies in the early universe.

Implications of the discovery and its contributions

The discovery of Ceers-2112 is expected to change at least two aspects of astronomy.

Alexander de la Vega

Alexander de la Vega is a postdoctoral researcher at the University of California, Riverside. Credit: Alexander de la Vega, UC Riverside

“First, theoretical models of galaxy formation and evolution will need to take into account that some galaxies became stable enough to host bars very early in the history of the universe,” de la Vega said. “These models may need to adjust for the amount of dark matter forming galaxies in the early universe, as dark matter is thought to affect the rate at which bars form. Second, the discovery of CEERS-2112 shows that structures like bars could be detected when the universe was very young. This Important because galaxies in the distant past were smaller than they are now, making the bars more difficult to find.The discovery of CEERS-2112 paves the way for the discovery of more bars in the young universe.

De la Vega helped the research team by estimating the redshift and properties of Ceers-2112. He also contributed to the interpretation of measurements.

“Redshift is an observable property of a galaxy that indicates how far away it is and how far back in time the galaxy can be seen, and it is a result of the finite speed of light,” he said.

What surprised de la Vega most about the discovery of Ceers-2112 was the extent to which its rod properties could be constrained.

“Initially, I thought that detecting and estimating the properties of bars in galaxies like SEARS-2112 would be fraught with measurement uncertainties,” he said. “But the power of the James Webb Space Telescope and the expertise of our research team helped us establish strong constraints on the size and shape of the bar.”

At UCLA, de la Vega oversees astronomy outreach. He plans telescope nights on and off campus, and makes visits to local schools to give presentations on astronomy. He also leads a series of public astronomy talks called “Cosmic Thursdays,” as well as one-off events for special occasions, such as eclipse viewing parties.

The paper is titled “A Milky Way-like barred spiral galaxy at redshift 3.”

Reference: “A Milky Way-like barred spiral galaxy at redshift 3” by Luca Costantin, Pablo G. Pérez González, Yuchen Gu, Chiara Buteta, Sharda Goji, Michaela B. Bagley, Guillermo Barro, Jehan S. Kartaltepe, Anton M. Kokemoyer, Cristina Capello, Enrico Maria Corsini, Jairo Méndez Abreu, Alexandre de la Vega, Karthik J. Iyer, Laura Bisgiello, Yingjie Cheng, Lorenzo Morelli, Pablo Arrabal Haro, Fernando Buitrago, M. C. Cooper, Avishay Dekel, Mark Dickinson, and Stephen L. Finkelstein, Mauro Giavalesco, Benny W. Holwerda, Mark Huertas-Company, and Ray A. Lucas, Casey Papovich, Nor Pierzkal, Liz-Marie Seely, Jesús Vega-Ferrero, Stijn Waits, and Leigh Aaron Young, November 8, 2023, nature.
doi: 10.1038/s41586-023-06636-x

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