A group of astronomers have used the ALMA telescope to discover a slowly-rotating galaxy within the early universe. That galaxy is the youngest ever discovered with a measured rotation, and it’s a lot slower than present-day galaxies.
All galaxies rotate, normally at improbable speeds. For instance, the Milky Manner galaxy has a rotation pace of over 200 kilometers consistent with 2nd. However astronomers don’t but know how galaxies construct as much as those speeds. The one technique to inform is thru measurements of galaxies all over cosmic time, build up a map of galactic evolution.
Just lately a group of astronomers primarily based at Waseda College in Tokyo used ALMA (the Atacama Huge Millimeter/submillimeter Array) in Chile to watch an especially far away galaxy. This galaxy, MACS1149-JD1, is up to now away that it’s in most cases some distance too dim to be seen. However the mild from that galaxy passes thru an enormous galaxy cluster, and the gravitational lensing from that cluster magnifies MACS1149-JD1. Astronomers can use this magnification to peer the galaxy.
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Measuring galaxy rotation
MACS1149-JD1 existed when the universe used to be handiest 500 million years previous, making it a number of the youngest recognized galaxies. The group used ALMA to check O III, or doubly-ionized oxygen, within the disk of the galaxy. They then advanced a fashion of the scale and rotation pace of the disk of the galaxy to match in opposition to observations. They reported their ends up in a paper just lately showing in The Astrophysical Magazine Letters.
The group discovered that MACS1149-JD1 is handiest 3,000 light-years throughout. This is some distance smaller than the Milky Manner galaxy, which is over 100,000 light-years throughout. Additionally they discovered that MACS1149-JD1 rotates at handiest 50 kilometers consistent with 2nd, which is not up to 1 / 4 of the Milky Manner’s rotation pace.
“The rotation pace of JD1 is way slower than the ones present in galaxies in later epochs and our [Milky Way] Galaxy and it’s most probably that JD1 is at an preliminary degree of growing a rotational movement,” says Akio Okay. Inoue, a co-author of the paper, additionally at Waseda College.
Those effects counsel that galaxies get started out small and rotate slowly. Then, over the process billions of years, they collect extra subject and building up their rotation fee. The group hopes to make use of the James Webb House Telescope to behavior additional research of galaxy rotation charges over cosmic time.