1,000+ New Star Clusters Detected by Telescopes

A team of international astronomers has leveraged the James Webb Space Telescope (JWST) to uncover over 1,000 new star cluster candidates in the Cigar Galaxy. Their findings were published on August 8 on the pre-print platform arXiv.

The Cigar Galaxy, also referred to as Messier 82, M 82, or NGC 3034, is a small, irregular starburst galaxy situated about 11.73 million light-years away in the constellation Ursa Major. It spans roughly 40,800 light-years and has a total mass of around 10 billion solar masses. It is among the closest starburst galaxies to our planet.

Earlier observations had identified 260 star clusters within 3,000 light-years of the galaxy's core and 363 clusters in its outer regions. Now, under the leadership of Rebecca C. Levy from Steward Observatory in Tucson, Arizona, the team used JWST’s Near Infrared Camera (NIRCam) to get a clearer picture of the galaxy's star clusters. This technology enabled them to discover and catalog new clusters that emit near-infrared light.

The researchers initially found 2,472 potential star clusters, but after further examination, they ruled out almost half as unreliable, leaving 1,357 valid candidates with masses of at least 10,000 solar masses. Notably, about 87% of these were new discoveries.

These clusters have a median radius of approximately 3.3 light-years and can possess stellar masses up to one million solar masses, totaling an estimated 40 million solar masses. The calculated mass function for these clusters was 1.9, which is consistent with findings from other starburst galaxies.

Additionally, the study revealed that these clusters are significantly obscured by dust, indicating they are relatively young and heavily reddened. The authors plan to conduct further research, focusing on more precise mass measurements through new spectroscopic observations in near-infrared and mid-infrared bands.