Astronomers discover globular cluster system of ultra-diffuse galaxy VCC 615

Astronomers have employed the Hubble Space Telescope (HST) to look at an ultra-diffuse galaxy often called VCC 615. Results of the observational marketing campaign, offered in a paper posted Dec. 2 to the preprint server arXiv, yield necessary insights into the globular cluster system of this galaxy.

Globular clusters (GCs) are collections of tightly sure stars orbiting galaxies. Astronomers understand them as pure laboratories enabling research on the evolution of stars and galaxies. In explicit, GCs may assist researchers to higher perceive the formation historical past and evolution of early-type galaxies, because the origin of GCs appears to be intently linked to durations of intense star formation.

VCC 615 is an ultra-diffuse galaxy positioned on the outskirts of the Virgo Cluster, some 57.7 million gentle years away. The galaxy has an efficient radius of roughly 7,300 gentle years, and its stellar mass is estimated to be 73 million photo voltaic plenty.

Recently, a workforce of astronomers led by J. Christopher Mihos of the Case Western Reserve University in Cleveland, Ohio, has used HST’s Advanced Camera for Surveys (ACS) to research the GC system in VCC 615, hoping that it may shed extra gentle on the properties of this galaxy.

“Our Hubble imaging lets us assemble a really clear and deep pattern of globular cluster candidates that extends greater than 90% down the globular cluster luminosity operate, whereas concurrently rejecting background galaxies that may be unresolved contaminants in ground-based imaging,” the researchers defined.

Mihos’s workforce managed to establish 22 GC candidates and the galaxy’s compact nucleus within the ACS subject of view, right down to a limiting magnitude of 24.0. Further inspection of the imagery discovered that 15 of those GC candidates are positioned inside 1.5 half-light radii from the middle of VCC 615.

According to the paper, six recognized GC candidates of VCC 615 stay unresolved, whereas for the opposite 16, the astronomers have decided half-light radii spanning throughout the vary 6.5–55.4 gentle years.

All in all, the whole globular cluster inhabitants for VCC 615 was estimated to be 25.1. This yields a globular cluster particular frequency at a stage of 55.5, which is kind of massive when in comparison with typical dwarf galaxies with related luminosity. Therefore, these findings counsel a big mass-to-light ratio for VCC 615.

The examine additionally discovered that VCC 615 has a complete mass between 90 and 160 billion photo voltaic plenty, and that the recognized compact nucleus is photometrically distinct from the galaxy’s GC inhabitants. The authors of the paper suppose that this nucleus could also be tidally stripped from VCC 615 sooner or later to type a brand new ultracompact dwarf galaxy.

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