HMN 2025: How Sweeping survey maps tons of of satellite tv for pc techniques orbiting dwarf galaxies

We often consider satellites as small objects orbiting planets or stars. But within the broader universe, galaxies themselves can have satellites—smaller galaxies certain by gravity that orbit a bigger host, carrying with them stars, gasoline, mud, and darkish matter.

Most of what we learn about satellite tv for pc galaxies comes from finding out the Milky Way and different equally massive galaxies. But a brand new study led by Dartmouth astronomers broadens that understanding by exploring the satellites of dwarf galaxies—techniques lower than a tenth the dimensions of the Milky Way.

The multi-institutional survey triples the variety of dwarf galaxies surveyed for satellites, the researchers report in The Astrophysical Journal. The study identifies 355 candidate satellite tv for pc galaxies, together with 264 that had been beforehand undocumented. The researchers counsel that 134 of those candidates are extremely more likely to be satellite tv for pc galaxies.

“Studying these techniques will help us piece collectively situations within the early universe,” says writer Burçin Mutlu-Pakdil, an assistant professor of physics and astronomy at Dartmouth.

“This venture fills a essential gap, providing recent insights into the method of how galaxies kind and its connection to darkish matter,” Mutlu-Pakdil says. “Our purpose is to construct a statistical pattern of the smallest galaxies within the universe, as they’re essentially the most dominated by darkish matter and function clear laboratories for understanding its nature.”

The survey was led by Laura Hunter, a postdoctoral fellow in Mutlu-Pakdil’s analysis group and corresponding writer of the research. In addition to Mutlu-Pakdil, co-authors of the research embrace Rowan Goebel-Bain ’25 and Guarini graduate pupil Emmanuel Durodola.

By analyzing the satellite tv for pc galaxies orbiting host galaxies of assorted sizes and environments, the researchers purpose to uncover how exterior situations affect satellite tv for pc formation. For occasion, research of enormous, Milky Way-sized galaxies counsel that bigger galaxies are inclined to host a higher variety of satellite tv for pc galaxies.

“With this survey, we’ll have the ability to check whether or not these predictions maintain true with a lot smaller host galaxies,” says Laura Hunter, a postdoctoral fellow in Mutlu-Pakdil’s analysis group and corresponding writer of the research.

“Astronomy is a area where you may’t run experiments,” Hunter says. “All you are able to do is observe and make as many measurements as you may, after which put that information right into a simulation and see whether or not it reproduces your observations. If it would not, that tells us that there is one thing flawed with our assumptions or our model of the universe.”

To seek for dwarf satellites, the staff analyzed publicly out there imaging information from the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys. They chosen 36 host galaxies to research, which diversified in measurement and of their proximity to different galaxies, since these elements might impression satellite tv for pc formation.

The researchers used an algorithm to take away “noise” from the photographs, reminiscent of brilliant sources of sunshine from different stars or galaxies, and to determine objects that might be satellite tv for pc galaxies. Then, they visually inspected every candidate satellite tv for pc to rule out those who had been as a result of picture defects or faint mild halos round brilliant stars or galaxies.

This survey is step one towards understanding how dwarf satellites differ from the satellite tv for pc galaxies of bigger hosts. The staff is at the moment conducting a follow-up marketing campaign to verify that the candidate satellites are certainly satellite tv for pc galaxies, and to characterize properties reminiscent of their measurement, distribution, how a lot gasoline and debris they include, and their charges of star formation.

“Getting the solutions would require plenty of assets and telescope time, however the impression might be unbelievable for understanding the character of darkish matter and galaxy formation on the smallest scale,” Mutlu-Pakdil says. “Each one in all them holds a bit of clue in regards to the physics of how galaxies kind.”