US, WASHINGTON (ORDO NEWS) — Astronomers explored the ultra-diffuse galaxy (UDG), known as VCC 1287, using the Keck Cosmic Web Imager (KCWI) tool to better understand its nature. New results provide important information about the mass of the galaxy and stellar kinematics. The study was presented in an article published May 6 on arXiv.
UDGs are extremely low density galaxies. The largest UDGs have dimensions similar to the Milky Way, but contain only about 1% of the stars in our home galaxy. The mystery of the UDG is still confusing scientists, trying to explain why these weak but large galaxies are not torn by the tidal field of their clusters.
Located at a distance of about 50 million light-years, VCC 1287 is a UDG with an estimated mass of about 4.5 billion solar masses, supposedly associated with the Virgo cluster. This is one of the first UDGs to receive an estimate of its mass. Previous observations of this galaxy suggest that this system is dominated by dark matter.
A team of astronomers led by John S. Gannon of the University of Swinburne, Australia, studied VCC 1287 more closely. They analyzed data from the KCWI instrument mounted on the Keck II telescope at WM Keck Observatory to study VCC 1287 stellar kinematics and put further restrictions on the mass of this galaxies.
“In our study, we present a kinematic analysis of an ultra-diffuse galaxy (UDG) in Virgo cluster VCC 1287 based on data obtained using the Keck Cosmic Web Imager,” astronomers write in the article.
The study also showed that VCC 1287 has a stellar recessive speed of about 1116 km / s, which confirms its connection with the Virgo constellation and its system of globular clusters, which were reported in previous observations. Astronomers added that the confirmed association of VCC 1287 with Virgo formalizes its large size and UDG status.
According to the document, VCC 1287 has a stellar velocity dispersion of about 19 km / s, which implies a dynamic mass of approximately 1.11 billion solar masses.
Scientists also estimated the mass of the halo VCC 1287 from its system of globular clusters. It was found that the mass of its halo is about 110 billion solar masses. This, according to the authors of the article, suggests that VCC 1287 is probably in a halo of dark matter with a core or low concentration.
Taking into account all the new results, astronomers concluded that tidal effects or stellar feedback could play a key role in the formation of VCC 1287. They added that the feedback scenario could be further explored by stellar population analysis.
Contact us: [email protected]