Astronomers discover two new Milky Way satellite galaxy candidates

For years, astronomers have nervous about the way to clarify why the Milky Way has fewer satellite galaxies than the usual dark matter mannequin predicts. That is referred to as the “lacking satellites drawback.”

As a way to deliver us nearer to fixing this drawback, a global group of researchers used knowledge from the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) to find two fully new satellite galaxies.

These outcomes had been published within the Publications of the Astronomical Society of Japan on June 8, 2024 by a group of researchers from Japan, Taiwan, and America.

We dwell in a galaxy referred to as The Milky Way, which has different, smaller galaxies orbiting it referred to as satellite galaxies. Learning these satellite galaxies can assist researchers unravel mysteries surrounding dark matter, and higher perceive how galaxies evolve over time.

“What number of satellite galaxies does the Milky Way have? This has been an necessary query for astronomers for many years,” remarks Masahi Chiba, a professor at Tohoku College.

The analysis group acknowledged the chance that there are seemingly many undiscovered, small satellite galaxies (dwarf galaxies) that are far-off and troublesome to detect. The highly effective capability of the Subaru telescope—which sits atop an remoted mountain above the clouds in Hawaii—is well-suited to seek out these galaxies. In actual fact, this analysis group beforehand discovered three new dwarf galaxies utilizing the Subaru telescope.

Now, the group has found an extra two new dwarf galaxies (Virgo III and Sextans II). With this discovery, a total of 9 satellite galaxies have been discovered by completely different analysis groups. That is nonetheless a lot fewer than the 220 satellite galaxies predicted by the usual idea of dark matter.

Nevertheless, the footprint of the HSC-SSP doesn’t cowl your entire Milky Way. If the distribution of these 9 satellite galaxies throughout your entire Milky Way is much like what was discovered within the footprint captured by the HSC-SSP, the analysis group calculates that there truly could also be nearer to 500 satellite galaxies. Now, we’re confronted with a “too many satellites drawback,” relatively than a “lacking satellites drawback.”

To higher characterize the precise quantity of satellite galaxies, extra high-resolution imaging and evaluation is required. “The subsequent step is to make use of a extra highly effective telescope that captures a wider view of the sky,” explains Chiba. “Subsequent yr, the Vera C. Rubin Observatory in Chile can be used to meet that function. I hope that many new satellite galaxies can be found.”