JWST improves understanding of distant starburst

A galaxy 12 million light years from Earth is brimming with new stars, NASA scientists have found.  

Pointing the James Webb Space Telescope at a patch of space in the constellation Ursa Major, they’ve found a galaxy where new stars are blooming at 10 times the speed of the Milky Way. 

This star factory is called Messier 82 (M82) and has long been considered a ‘prototype’ starburst galaxy. Like many assignments the JWST has been tasked with, M82 has been previously observed using both the Spitzer and Hubble space telescopes.  

M82 starburst
Credit: NASA, ESA, CSA, STScI, A. Bolatto (University of Maryland)

Using the JWST’s onboard Near Infrared Camera, the lens was able to cut through layers of dust and gas to clearly spot emerging stars and star clusters and the elements surrounding them, such as hydrogen and iron.  

It was also able to see long swirling patterns of material extending from the galaxy’s core – a galactic wind. The researchers sought to understand how this product of mass star formation is created and propelled out from the galactic plane. Using NIRCam to track polycyclic aromatic hydrocarbons – basically, specks of space dust carried through this wind – the research group was able to observe its journey out from the starforming galactic centre. 

“M82 has garnered a variety of observations over the years because it can be considered as the prototypical starburst galaxy,” says Alberto Bolatto, a professor in the University of Maryland’s astronomy department. He led the study, which has been accepted for publication in The Astrophysical Journal, and was uploaded to the preprint server ArXiv. 

“It was unexpected to see the PAH [polycyclic aromatic hydrocarbon] emission resemble ionised gas. PAHs are not supposed to live very long when exposed to such a strong radiation field, so perhaps they are being replenished all the time. It challenges our theories and shows us that further investigation is required.”  

According to NASA, the study team will shortly have detailed spectroscopic data and larger-scale images of M82’s wind patterns for analysis. Bolatto expects this to enable calculations of the galaxy’s age and the environment of the early universe: “Webb’s observation of M82, a target closer to us, is a reminder that the telescope excels at studying galaxies at all distances,” he says. 

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