NAOJ: Machine Learning Finds a Surprising Early Galaxy

Find out the latest thinking about our universe.
User avatar
bystander
Apathetic Retiree
Posts: 20386
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

NAOJ: Machine Learning Finds a Surprising Early Galaxy

Post by bystander » Sat Aug 01, 2020 4:42 pm

Machine Learning Finds a Surprising Early Galaxy
Breaking the Lowest Oxygen Abundance Record

Subaru Telescope | National Astronomical Observatory of Japan | 2020 Jul 31
New results achieved by combining big data captured by the Subaru Telescope and the power of machine learning have discovered a galaxy with an extremely low oxygen abundance of 1.6% solar abundance, breaking the previous record of the lowest oxygen abundance. The measured oxygen abundance suggests that most of the stars in this galaxy formed very recently.

To understand galaxy evolution, astronomers need to study galaxies in various stages of formation and evolution. Most of the galaxies in the modern Universe are mature galaxies, but standard cosmology predicts that there may still be a few galaxies in the early formation stage in the modern Universe. Because these early-stage galaxies are rare, an international research team searched for them in wide-field imaging data taken with the Subaru Telescope. ...

However, it was difficult to find galaxies in the early stage of galaxy formation from the data because the wide-field data includes as many as 40 million objects. So the research team developed a new machine learning method to find such galaxies from the vast amount of data. They had a computer repeatedly learn the galaxy colors expected from theoretical models, and then let the computer select only galaxies in the early stage of galaxy formation.

The research team then performed follow-up observations to determine the elemental abundance ratios of 4 of the 27 candidates selected by the computer. They have found that one galaxy (HSC J1631+4426), located 430 million light-years away in the constellation Hercules, has an oxygen abundance only 1.6 percent of that of the Sun. This is the lowest values ever reported for a galaxy. The measured oxygen abundance suggests that most of the stars in this galaxy formed very recently. In other words, this galaxy is undergoing an early stage of the galaxy evolution. ...

Surprisingly Young Galaxy Breaks Low-Oxygen Record
W.M. Keck Observatory | 2020 Jul 31

Extremely Metal-Poor Representatives Explored by the Subaru Survey (EMPRESS).
I. A Successful Machine Learning Selection of Metal-Poor Galaxies and the
Discovery of a Galaxy with M*<10^6 M and 0.016 Z
~ Takashi Kojima et al
Last edited by bystander on Mon Aug 03, 2020 6:29 pm, edited 1 time in total.
Reason: Added Keck article and links
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor