Astronomers have discovered one of the largest structures ever seen in...

After about 370,000 years, hydrogen formed, the basic building block of stars, which fuse hydrogen and helium in their interior to form all of the heavier elements. While hydrogen remains the most prevalent element in the universe, individual clouds of hydrogen gas can be difficult to detect in the interstellar medium (ISM).

This makes it difficult to research the early stages of star formation, which would provide clues about the evolution of galaxies and the universe.

An international team led by astronomers from Max Planck Institute for Astronomy (MPIA) recently noticed the presence of huge filaments of atomic hydrogen gas in our galaxy. This structure, named ‘MaggieIt lies about 55,000 light-years away (on the opposite side of the Milky Way) and is one of the tallest structures ever observed in our galaxy.

(ESA / Gaia / DPAC / T. Müller / J. Syed / MPIA)

Above: The section of the Milky Way, as measured by the European Space Agency’s Gaia satellite (top). The square indicates the location of the “Maggie” filament and the false-colored image of the atomic hydrogen distribution (bottom), the red line indicates the “Maggie” filament.

The study describing their findings recently appeared in the journal Astronomy and astrophysics, led by Jonas Seid, Ph.D. Student at MPIA.

He was joined by researchers from the University of Vienna Harvard-Smithsonian Center for Astrophysics (CfA) ، و Max Planck Institute for Radio Astronomy (MPIFR), University of Calgary, University of Heidelberg, Center for Astrophysics and Planetary Sciences, the Argelander- Institute of Astronomyand the Indian Institute of Science and NASA’s Jet Propulsion Laboratory (JPL).

The research is based on the data obtained HI/OH/Recombination Line Survey of the Milky Way (THOR), a monitoring software based on Extra large collection of Karl G. Jansky (VLA) in New Mexico.

Using the VLA’s centimeter-wave radio dishes, this project studies the formation of molecular clouds, the conversion of atoms into molecular hydrogen, the galaxy’s magnetic field, and other questions related to the ISM and star formation.

The ultimate goal is to determine how the two most common hydrogen isotopes converge to form dense clouds that rise to new stars. Isotopes include atomic hydrogen (H), consisting of one proton, one electron, and no neutrons, and molecular hydrogen (H2) – or deuterium – consisting of one proton, one neutron, and one electron.

The latter only condense into relatively compact clouds that will develop frosty regions where new stars eventually appear.

The process of the transition of atomic hydrogen to molecular hydrogen is still largely unknown, which made this extremely long thread a particularly exciting discovery.

While the largest known clouds of molecular gas are about 800 light-years long, Magi is 3,900 light-years long and 130 light-years wide. As Syed explained in a recent MPIA press release:

“The website of this thread has contributed to this success. We don’t yet know exactly how he got there. But the filament extends about 1,600 light-years below the plane of the Milky Way. The observations also allowed us to determine the velocity of hydrogen gas. This allowed us to show that the velocities along the filament hardly differ.”

The team’s analysis showed that the material in the filament has an average velocity of 54 km/s^-1, which they primarily determined by measuring against the rotation of the Milky Way’s disk. This means that the radiation has a wavelength of 21 cm (aka “hydrogen line”) was visible against the cosmic background, making the structure recognizable.

“The observations also allowed us to determine the velocity of hydrogen gas,” said Henrik Beuther, THOR president and study co-author. “This allowed us to show that the velocities along the filament hardly differ.”

From this, the researchers concluded that Maggi is a coherent structure. These results confirmed observations made a year ago by Juan de Soler, an astrophysicist at the University of Vienna and co-author of the paper.

When he noticed the thread, he named it the longest river in his native Colombia: the Río Magdalena (English: Margaret, or “Maggie”). While Maggie could have been identified in Soler’s previous assessment of the THOR data, only the current study demonstrated beyond a reasonable doubt that it is a coherent structure.

Based on previously published data, the team also estimated that Magee contains 8 percent molecular hydrogen by mass.

Upon closer examination, the team noticed that the gas converged at various points along the filament, leading them to conclude that hydrogen gas was accumulating in large clouds at those locations. They also predicted that the atomic gas would gradually condense into a molecular form in those environments.

“However, many questions remain unanswered,” Syed added. “The additional data, which we hope will give us more clues about the molecular gas fraction, is already waiting to be analyzed.”

Fortunately, several space and ground-based observatories will soon be operational, and telescopes that will be equipped to study these filaments in the future. These include James Webb Space Telescope (JWST) and radio polls such as square kilometer array (SKA), which will allow us to view the earliest period of the universe (“cosmic dawn”) and the first stars in our world.

This article was originally published by universe today. Read the original article.