Capturing the Beginning of Galaxy Rotation in the Early Universe

Spiral Galaxy

Astronomers detect the most distant galaxy rotation ever, suggesting an initial stage of rotational motion development.

Astronomers have been able to detect more and more distant galaxies as telescopes have become more advanced and powerful. Since light travels at a finite speed and we see objects as they were when the light was emitted, the farther away something is, the farther back in time we are seeing. Therefore, these very distant galaxies are some of the earliest galaxies to form in our universe, which began to recede away from us as the universe expanded.

In fact, the greater the distance, the faster a galaxy appears to move away from us. Interestingly, we can estimate how fast a galaxy is moving, and in turn, when it was formed based on how “redshifted” its emission appears. This redshift is similar to a phenomenon called “Doppler effect,” where objects moving away from an observer emit the light that appears shifted towards longer wavelengths (hence the term “redshift”) to the observer.

Located in the midst of the Atacama Desert in Chile, the Atacama Large Millimeter/submillimeter Array (ALMA) telescope is especially well-suited for observing such redshifts in galaxy emissions. Recently, an international research team observed redshifted emissions of a distant galaxy, MACS1149-JD1 (hereafter JD1), which has led them to some fascinating conclusions. “Beyond finding high-redshift, namely very distant, galaxies, studying their internal motion of gas and stars provides motivation for understanding the process of galaxy formation in the earliest possible universe,” explains Ellis.

The team of international researchers included Professor Akio Inoue and graduate student Tsuyoshi Tokuoka from Waseda University, Japan, Dr. Takuya Hashimoto at the University of Tsukuba, Japan, Professor Richard S. Ellis at University College London, and Dr. Nicolas Laporte, a research fellow at the University of Cambridge, UK. The findings of their study have been published in The Astrophysical Journal Letters.

Rotation Signature of Distant Galaxy Hints at Early Formation Epoch

After the Big Bang came the earliest galaxies. Due to the expansion of the universe, these galaxies are receding away from us. This causes their emissions to be redshifted (shifted towards longer wavelengths). By studying these redshifts, it is possible to characterize the “motion” within the galaxies as well as their distance. In a new study, astronomers at Waseda University have now revealed a likely rotational motion of one such distant galaxy. Credit: Waseda University

Galaxy formation starts with the accumulation of gas and proceeds with the formation of stars from that gas. Over time, star formation progresses from the center outward, a galactic disk develops, and the galaxy acquires a particular shape. As star formation continues, newer stars form in the rotating disk while older stars remain in the central part. It is possible to determine the stage of evolution the galaxy has reached by studying the age of the stellar objects and the motion of the stars and gas in the galaxy.

After conducting a series of observations over a period of two months, the astronomers successfully measured small differences in the “redshift” from position to position inside the galaxy. They found that JD1 satisfied the criterion for a galaxy dominated by rotation. Next, the scientists modeled the galaxy as a rotating disk and discovered that it reproduced the observations very well. The calculated rotational speed was about 50 kilometers per second (110,000 miles per hour), which was compared to the rotational speed of the Milky Way disk of 220 kilometers per second (500,000 miles per hour). The team also measured the diameter of JD1 at only 3,000 light-years, much smaller than that of the Milky Way at 100,000 light-years across.

The significance of their result is that JD1 is by far the most distant and, therefore, earliest source yet found that has a rotating disk of gas and stars. Together with similar measurements of nearer systems in the research literature, this has allowed the team to delineate the gradual development of rotating galaxies over more than 95% of our cosmic history.

Furthermore, the mass estimated from the rotational speed of the galaxy was in line with the stellar mass previously estimated from the galaxy’s spectral signature, and came predominantly from that of “mature” stars that formed about 300 million years ago. “This shows that the stellar population in JD1 formed at an even earlier epoch of the cosmic age,” says Hashimoto.

“The rotation speed of JD1 is much slower than those found in galaxies in later epochs and our Galaxy and it is likely that JD1 is at an initial stage of developing a rotational motion,” says Inoue. With the recently launched James Webb Space Telescope, the astronomers now plan to identify the locations of young and older stars in the galaxy to verify and update their scenario of galaxy formation.

New discoveries are surely on the horizon!

Reference: “Black Hole to Photosphere: 3D GRMHD Simulations of Collapsars Reveal Wobbling and Hybrid Composition Jets” by Ore Gottlieb, Matthew Liska, Alexander Tchekhovskoy, Omer Bromberg, Aretaios Lalakos, Dimitrios Giannios and Philipp Mösta, 29 June 2022, The Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/ac7530

3 Comments on "Capturing the Beginning of Galaxy Rotation in the Early Universe"

  1. Charles G. Shaver | July 23, 2022 at 11:58 am | Reply

    In my unorthodox model of the universe pulsing gravity radiates outward from all objects and the speed of light varies, with photons accelerating away from their sources and decelerating in our solar field of gravity upon arrival. Therefore, the size, age and expansion of the universe are still to be determined.

  2. Bruce H Truth | July 24, 2022 at 1:20 am | Reply

    The “Big Bang” is only an unproven hypothesis. The statement we can look back in time based on distance is based solely on an unproven hypothesis. Don’t sell imagination as fact. Besides this, I enjoyed the article.

  3. “Galaxy formation starts with the accumulation of gas and proceeds with the formation of stars from that gas”

    Why is this statement considered a fact? Is it the Big Bang “theory” or Big Bang “fact”. Why is gravity assumed to do so much in our universe? The only reason it is is because scientists had nothing else to use when the universe was “born” made of “quark gluon plasma” that cooled to hydrogen. Science was forced to create a “free energy” and it did it with the wrong force because gravity doesn’t create energy, energy creates gravity.

    These galaxies are spinning because they are shrapnel from a massive collision that happened 13.8 billion years ago in an already existing, static universe. Everything was already here when the Big Bang happened just like the first law states it was. The reason galaxies are where they shouldn’t be and spinning when they shouldn’t be is because they were shrapnel from the collision. Each galaxy was born the second the Big Bang happened and has cooled ever since. Each galaxy had its own size, shape, rotational rate, and trajectory. Some galaxies like ours were spinning to create spiral galaxies and some weren’t to create elliptical or irregular galaxies. With this theory, everything is explained perfectly following all the laws of physics it should.

    The reason there is no quantum explanation for gravity is because it is forced to do something it cannot do. Using it to turn a cloud of gas and dust into a star is simply impossible and is why it goes unexplained. Since the collision created all the energy and not gravity, space is allowed to be manipulated by energy to create gravity just like Einstein said. His one true blunder came when he decided to accept Georges Lamaîtres interpretation of Hubbles expanding galaxies even though he flat out accused the theory of being “abominable” as far as physics go. It seems obvious that Einstein was much more religious than the scientific community thinks.

    The scientists in this article should retract the fact that they solved a long-standing theory. They did not. What they consider facts are nothing of the sort. The particle colliders create quark plasma shrapnel and our universe created quark plasma shrapnel as the galaxies.

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