Giant Molecular Cloud Discovered in Milky Way Galaxy Baffles Experts

A massive discovery from the Milky Way Galaxy can provide researchers with more insights regarding the star formation process. The discovery is a giant molecular cloud (GMC) around 200 light years in size. Experts detected it in the middle of a dust lane in the Milky Way's Bar (a band of stars in the center of the galaxy). Astronomers named the newly discovered giant molecular cloud M4.7-0.8. The cloud is estimated to be 23,000 light years from Earth. Based on their examinations, researchers concluded that the GMC was involved in manufacturing stars. Findings regarding this giant molecular cloud have been published in the journal Astrophysics of Galaxies.

Discovery of Giant Molecular Cloud

The M4.7-0.8 was detected using data gathered by the Green Bank Telescope (GBT). Researchers registered emissions from dense gas exhibiting a frequency of 25 GHz, associated with the GMC, using data from the telescope. If a molecular cloud ranges from 15 to 600 light years in diameter, then experts categorize it as a GMC. Hence, M4.7-0.8 was deemed to be a "Giant Molecular Cloud." 

GMCs are made out of interstellar gas and dust left over by the formation of galaxies. The most dominant ingredient of such clouds is typically the hydrogen molecule. These gas reservoirs are known to be one of the coldest and densest regions of the interstellar medium. M4.7-0.8 appears to be no different, according to the study. Based on examinations, experts estimated the molecular cloud's length to be around 195 light years in Galactic longitude and sporting a vertical extent of 65 light years in Galactic latitude. M4.7-0.8's mass was determined to be 160,000 solar masses, and the temperature of its cold dust was 20 K, reported Phys.org.

Features of the Molecular Cloud

The size, mass, and temperature of M4.7-0.8 helped researchers identify two main parts of this GMC. These parts were named "Nexus" and "Filament" by experts. Nexus exhibited bright carbon monoxide (CO) emission and supposedly interacted with the dust continuum of the cloud. The dust continuum was labeled filament and appeared to be narrow in shape. Researchers further added that the part exhibited a filamentary morphology. Also, they discovered a shell-shaped structure inside the cloud. The structure had a bright rim in the region where they detected ammonia emission, surrounding a cavity-like area. 

Role of Star Formation

The dust lane where the GMC was detected has been recognized as an important region for the transportation of material that happens from the galaxy's disc to its center. This material is then used to create ring-like structures, which eventually host star formation. Based on the positioning of M4.7-0.8, researchers claimed that the GMC possibly played an important role in star formation within this galaxy. 

During the examination, researchers also located two possible sites inside the cloud where they believe stars are being formed. These two sites were named Knot B and Knot E. Knot E was deemed to be dense and displayed a comet-like structure. The team claimed that to confirm this star-making hypothesis, they wanted to conduct a more in-depth analysis. Researchers encouraged further examination of this structure to learn more about the complicated star-making process, as well as galaxy evolution.

For more information on the study, you can find it in the journal Arxiv.