Physicists Just Mapped A Stellar, Galactic Burp of Astronomical Proportions

“That’s a lot of gas!”

Bright spots, of different sizes, pepper the right side of a galaxy where a bright disk shines at it...
Credit: ESO/A. Watts et al

Astronomers just mapped, in great detail, a galactic burp.

In a new study out today in the journal Monthly Notices of the Royal Astronomical Society, researchers created a high-resolution map of galaxy NGC 4383, revealing an outflow of gas of gigantic proportions.

The ejection is spectacularly disruptive. According to the research announcement, its mass is the equivalent of more than 50 million Suns.

“We had no idea that the gas outflow was so complex and beautiful,” Barbara Catinella, research professor at the University Western Australia’s International Centre for Radio Astronomy Research (ICRAR), tells Inverse via email. ICRAR colleague Luca Cortese echoed the sentiment to Inverse. “The level of details visible in the map was clearly above expectations.”

Massive expulsions like this one deplete a galaxy of ingredients for making new stars. Researchers suspect older stars may be to blame, as they radiate charged particles, creating harsh stellar winds. The most senior stars die as supernovas, whose energies also power the outflows. But, they’re incredibly hard to see.

Enter the new high-resolution map, which reveals these spurts — tens of thousands smaller than the whole galaxy — and their overall effect.

Derived hydrogen alpha emission lines reveal the “complex and clumpy distribution and motions” of the gas in the galaxy, according to the paper authors. Here, structures like “chimneys” and “shells” associated with the outflow of gas also appear.

A.B. Watts et al.

This outflow of gas is gigantic. Light takes 20,000 years to cross the newly-rendered belch. For perspective, humans left the earliest-known footprints in North America when this light began traversing. The massive structure contains myriad colors from elements such as hydrogen, oxygen, sulfur, and nitrogen. Plumes, filaments, and complex structures abound.

“We knew that something unusual was happening in this galaxy, but we did not have enough info to really understand what was going on,” Cortese says.

The data collection took four hours. Astronomers harnessed the sensitivity of an optical telescope called the MUSE Integral Field Spectrograph. This instrument sits on the Very Large Telescope, from the European Southern Observatory (ESO), located in Chile.

“That’s a lot of gas!” Researchers Adam Watts and Barbara Catinella discuss their new work.


MUSE revealed how the galaxy was distributing more than 3,000 different wavelengths of light. The final result is a revelation for the researchers. Gas by the millions of solar masses appears to hurtle outwards from the galaxy’s core at more than 200 kilometers per second. Once outside, it floats in the intergalactic medium possibly forever.

Now, the team wants to understand how galaxies evolve — and what can stunt their growths. “This image not only allows us to reveal the complex morphology of this massive explosion,” Cortese says, “but it also provides us with critical info on the velocity, mass, and chemical composition of the gas being ejected from the disk of the galaxy.”

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