galactic quenching Archives

September 16, 2024September 16, 2024 by Evan Gough

A Black Hole has Almost Halted Star Formation in its Galaxy

This is a quiescent galaxy in the early Universe named GS-10578 but nicknamed ‘Pablo’s Galaxy’. It has an SMBH in its center, and astronomers have used the NASA/ESA James Webb Space Telescope to confirm that supermassive black holes can starve their host galaxies of the fuel they need to form new stars. Image Credit: JADES Collaboration

When the James Webb Space Telescope was launched on Christmas Day in 2021, it faced a whole host of intriguing questions. By the time it finally launched, astronomers had a big list of targets begging for the type of detailed observations that only the powerful infrared space telescope could perform. One of the targets was an ancient, massive galaxy that’s basically dead and forms no new stars.

The results are in, and an international team of astronomers know what happened to the quiescent galaxy.

February 5, 2024February 5, 2024 by Evan Gough

The JWST Discovers a Galaxy That Shouldn’t Exist

The JWST captured this image of an unusual quiescent dwarf galaxy in the background of separate observations. Image Credit: Carleton et al. 2024

Astronomers working with the JWST found a dwarf galaxy they weren’t looking for. It’s about 98 million years away, has no neighbours, and was in the background of an image of other galaxies. This isolated galaxy shows a lack of star-formation activity, which is very unusual for an isolated dwarf.

Most isolated dwarf galaxies form stars, according to a wealth of observations. What’s different about this one?

November 8, 2023November 8, 2023 by Evan Gough

What Can Slime Mold Teach Us About the Universe?

A simulation of the cosmic web, diffuse tendrils of gas that connect galaxies across the universe. Credit: Illustris Collaboration

What can slime molds tell us about the large-scale structure of the Universe and the evolution of galaxies? These things might seem incongruous, yet both are part of nature, and Earthly slime molds seem to have something to tell us about the Universe itself. Vast filaments of gas threading their way through the Universe have a lot in common with slime molds and their tubular networks.

September 19, 2023September 19, 2023 by Evan Gough

Galaxies Breathe Gas, and When They Stop, No More Stars Form

Artist concept of how a galaxy might accrete mass from rapid, narrow streams of cold gas. These filaments provide the galaxy with continuous flows of raw material to feed its star-forming at a rather leisurely pace. Credit: ESA–AOES Medialab

For most of the history of astronomy, all we could see were stars. We could see them individually, in clusters, in nebulae, and in fuzzy blobs that we thought were clumps of stars but were actually galaxies. The thing is, most of what’s out there is much harder to see than stars and galaxies. It’s gas.

Now that astronomers can see gas better than ever, we can see how galaxies breathe it in and out. When they stop breathing it, stars stop forming.

November 3, 2021November 3, 2021 by Evan Gough

What’s Snuffing Out Galaxies Before Their Time?

The VERTICO—Virgo Environment Traced in Carbon Monoxide—Survey observed the gas reservoirs in 51 galaxies in the nearby Virgo Cluster and found that the extreme environment in the cluster was killing galaxies by robbing them of their star-forming fuel. In this composite image, ALMA’s radio wavelength observations of the VERTICO galaxies’ molecular gas disks are magnified by a factor of 20. They are overlaid on the X-ray image of the hot plasma within the Virgo Cluster. Credit: ALMA (ESO/NAOJ/NRAO)/S. Dagnello (NRAO)/Böhringer et al. (ROSAT All-Sky Survey)

In the Milky Way, the formation rate of stars is about one solar mass every year. About 10 billion years ago, it was ten solar masses every year. What happened?

Stars are born in giant molecular clouds (GMCs), and astronomers think that the environment in galaxies affects these clouds and their ability to spawn new stars. Sometimes the environment is so extreme that entire galaxies stop forming new stars.

Astronomers call this “quenching,” and they want to know what causes it.