Mauna Kea Observatories Put New Spin on Galaxy Formation

W. M. Keck Observatory press release

A team of Australian researchers used two Maunakea-based observatories – Gemini North and W. M. Keck Observatory – to discover why some galaxies are clumpy rather than spiral in shape and it appears that low spin is to blame. The finding challenges an earlier theory that high levels of gas cause clumpy galaxies, and sheds light on the conditions that brought about the birth of most of the stars in the Universe. The finding was published today in The Astrophysical Journal.

Galaxy Velocity
The massively star-forming galaxies analyzed in this study have clumpy, turbulent gas shown here in false colors. Credit: W. M. Keck Observatory/Gemini Observatory/Hubble
“This result was obtained by a unique and unusual combination of TWO large telescopes,”said Swinburne University astronomer Professor Karl Glazebrook, co-author and leader of the survey team “We used Keck adaptive optics to probe the fine details of galaxy rotation and Gemini to look at the large scale distribution. This made possible a result that was not before known about the spin of early primitive galaxies. It is one of the most exciting results of my career.”

A combination of integral field spectroscopy data from Keck Observatory and Gemini Observatory was the key to obtaining measurements for a galaxy’s spin. Keck Observatory’s OSIRIS instrument collected data high spatial resolution in the galaxy centers, and the Gemini Multi-Object Spectrograph (GMOS) collected data for high surface brightness sensitivity out to large radii.

Lead author Dr. Danail Obreschkow, from The University of Western Australia (UWA) node of the International Centre for Radio Astronomy Research (ICRAR), said that ten billion years ago the Universe was full of clumpy galaxies, but these developed into more regular objects as they evolved; the majority of stars in the sky today, including our five billion-year-old Sun, were probably born inside these clumpy galaxies.

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