Subject: Early galaxies and their structures - Comments and suggestions are welcome! Don't hesitate and leave a comment on our comment section down below the article!
Spiral Galaxy - Left: an image of the ALESS 112.1 spiral galaxy, 10 billion light-years away from us. The image was made with the ALMA telescopes. Right: NGC 5247, a spiral galaxy 'just' 50 million light years away from us. - Image Credit: Left: ALMA/Jacqueline Hodge et al. Right: ESO/P. Grosbøl
Young galaxies are less messy than expected and also appear to contain spiral arms, bars and rings according to an international team of researchers led by Jacqueline Hodge (Leiden University). The young galaxies, located at a large distance from us, have until now been hazy dots, but were first shown in more detail by the ALMA telescope in Chile. The researchers will soon publish their findings in The Astrophysical Journal.
The researchers zoomed in on the constellation Fornax on the southern sky. Approximately twenty years ago, astronomers discovered a new collection of galaxies that were created just a few billion years after the Big Bang. Back then telescopes were not good enough to produce images with enough detail as they they only showed distant galaxies as vague spots.
The astronomers made their new observations with the Atacama Large Millimeter / submillimeter Array (ALMA) in northern Chile which consists of a collection of radio dishes that operate at millimeter wavelengths and have little trouble with gas and dust clouds around distant galaxies.
The observed bars, rings and spiral arms came as a surprise to astronomers. They always thought that regular structures of this kind only occur with fully grown, more or less settled galaxies and not with young galaxies.
Barred galaxy - Left: an image of the ALESS 17.1 galaxy 10 billion light-years away from us. The image was made with the ALMA telescopes. The elongated white spot indicates a bar-shaped structure. Right: NGC1300, a similar barred galaxy that is only 61 million light-years away from us - Image Credit: Left: ALMA/Jacqueline Hodge et al. Right:: ESO/P. Grosbøl
The researchers are particularly delighted with the bar-shaped structures. Bars are a kind of tube that leads gas to the center of a galaxy. As a result, new stars can arise quickly. Lead researcher Jacqueline Hodge (Leiden University): stated that scientists already knew that there was rapid star formation, but could not explain it very well. Thanks to the recently discovered bar-shaped structures, the rapid star formation can now be explained much more easily.
Earlier, in 2013, Jacqueline Hodge and colleagues observed the same piece of universe and discovered that what used to look like a galaxy was often two or more galaxies. In 2019 astronomers where able to see clear structures for the first time.
In the future astronomers want to study the young galaxies at different time intervals, that way they get an indication of movement in the galaxies helping them to test their hypothesis about rapid star formation.
Source: NOVA press release - Further reading: https://arxiv.org/abs/1810.12307
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