13.8 billion years ago our world was born in a huge explosion called the Big Bang. The explosion created the first subatomic particles and physical laws we know today. About 370,000 years after the birth of the universe, the element hydrogen was formed, which is the building block of stars. Hydrogen and helium melting inside the stars produced heavier elements. Although hydrogen remains the most pervasive element in the universe, independent clouds of hydrogen gas can hardly be detected in interstellar space. For this reason, it is difficult to study the first phases of star formation, which provide clues about the evolution of galaxies and the universe.
Now an international team led by astronomers at the Max Planck Institute for Astronomy (MPIA) has just identified massive strands of atomic hydrogen gas in the galaxy. This structure that Maggie It is located 55,000 light-years across the Milky Way and is one of the longest structures observed in the galaxy.
Above: Part of the Milky Way photographed by the European Space Agency on the Gaia satellite. In the rectangle, the position of the Maggie string in the false color mode is indicated. This string shows the distribution of atomic hydrogen (bottom). The red line indicates Maggie.
The paper was published in the journal Astronomy & Astrophysics under the supervision of Jonas Syed, an MPIA PhD student. Jonas with researchers at the University of Vienna, Harvard Smithsonian Institution of Astrophysics (CfA), Max Planck Institute for Radio Astronomy (MPIFR), University of Calgary, University of Heidelberg, Center for Astrophysics and Planetary Science, Erglander Institute of Astronomy, Laboratory Cooperates.
The study used recombinant linear mapping data / OH / HI or THOR, which is one of the VLA (very large array) observatory programs. Using VLA centimeter-wave radio plates, the project examines the formation of a molecular cloud, the conversion of atomic hydrogen to a molecule, the galaxy’s magnetic field, and other questions about interstellar space and star formation.
The main goal of the project is to figure out how two common types of hydrogen gas convergence formed to form dense clouds that led to the formation of new stars. These two types are atomic hydrogen (H) and molecular hydrogen (H2). Atomic hydrogen (H) is a hydrogen atom composed of one proton and one electron and has no neutrons; But molecular hydrogen (H2) is made up of two hydrogen atoms that are covalently bonded together. It goes without saying that only molecular hydrogen takes the form of relatively compact clouds, paving the way for the formation of new stars.
The process of transition from atomic hydrogen to molecular hydrogen is still unknown. While the longest known molecular gas clouds are 800 light-years long, Maggie is 3,900 light-years long and 130 light-years wide. Syed says in the recent meeting:
Maggie’s string position influenced our success. We still do not know what is going on in Maggie; But the string has been developed for nearly 1,600 light-years under the Milky Way plate. Observations also allow us to determine the initial velocity of hydrogen gas. Thus, we can show that the velocities do not differ much along the string.
The researchers’ analysis shows that the material in the field has an average speed of 54 kilometers per second. This speed was obtained by measuring relative to the Milky Way disk; As a result, radiation at a wavelength of 21 cm relative to the cosmic background was detected, leading to the discovery of this structure. “THOR’s supervisor, Henrik Butter, one of the authors of the study, says:
With observations we were able to determine the initial velocity of the hydrogen gas. In this way, we can show the difference in low velocities along the string.
The researchers concluded that Maggie is a cohesive structure. These findings confirm the one-year observations of Juan Disuller, an astrophysicist at the University of Vienna and one of the authors of the paper. After seeing the range, he named Colombia’s longest river, م his native land: Rio Magdalena, abbreviated Margaret or Maggie. Although Maggie was identifiable on the THOR data at the first Soler assessment, only the current investigation cleared up any doubts.
Based on previous data, the researchers found that 8% of Maggie is made up of molecular hydrogen. They took a closer look at the gas converging at different points in the series, and thus concluded that the hydrogen gas had condensed into large clouds in these situations. Then, they found that atomic gas gradually became molecular in these environments. Seyed adds:
Many questions remain unanswered. We hope that more data will reveal clues about the molecular gas sector.
Fortunately, a series of ground and space observations will begin soon, and equipped telescopes will study these structures in the future. These technologies include the James Webb Space Telescope (JWST) and radio maps such as the Square Kilometer Array (SKA), which allow us to study cosmic beginnings and the first stars of the universe.
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