March 1, 2024

New Study Reveals that the Small Magellanic Cloud is Actually Two Separate Galaxies

A recent study conducted by a team of astronomers and astrophysicists from various international institutions has provided evidence that challenges the long-held belief that the Small Magellanic Cloud (SMC) is a single galaxy. The findings, which have been detailed in a paper published on the arXiv preprint server, indicate that the SMC is, in fact, composed of two distinct dwarf galaxies.

For many years, the Magellanic Clouds have been recognized as irregular dwarf galaxies that appear to be located in close proximity to one another in the southern celestial hemisphere. These galaxies have been known individually as the Large Magellanic Cloud and the Small Magellanic Cloud, based on their respective sizes. However, in the late 1980s, preliminary evidence emerged suggesting that the SMC may consist of two dwarf galaxies. The new study reinforces this hypothesis, providing further evidence to support the idea that the SMC is comprised of two smaller galaxies.

These observations enabled the scientists to estimate the average velocity of stars in different regions of the SMC. Subsequently, the team utilized data from the Galactic Australian Square Kilometer Array Pathfinder, an expansive radio telescope array located in Western Australia, to gain insights into the interstellar medium within both the SMC and the Large Magellanic Cloud (LMC). In addition, the researchers analyzed data from the APOGEE survey, which involved the use of dual 300-fiber spectrographs positioned at the Sloan Foundation Telescope and the NMSU Telescope, situated at the Apache Point Observatory in New Mexico.

By taking into account all of the collected evidence, the researchers uncovered distinct differences in the chemical composition of two regions within the SMC. Furthermore, they observed variations in velocities between the two parts, with faster movement occurring in the section that appeared to be closer relative to Earth. Notably, the team determined that both components possessed similar masses and were interacting with the LMC.

Based on these findings, the researchers confidently concluded that the SMC is comprised of two distinct galaxies, with one galaxy positioned almost directly behind the other, when viewed from Earth. This particular arrangement explains why the presence of two galaxies within the SMC went unnoticed until relatively recently.

The team also made calculations regarding the distances between Earth and the two galaxies. Notably, they estimated that the closer of the two galaxies is situated approximately 199,000 light years away, while the more distant galaxy is located approximately 215,000 light years away.

This groundbreaking study challenges our previous understanding of the Small Magellanic Cloud and reveals new insights into its composition and structure. By recognizing that the SMC is actually two separate galaxies, astronomers can now further explore the dynamics and interactions within this fascinating celestial phenomenon.

1. Source: Coherent Market Insights, Public sources, Desk research
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