Astronomers from the College of Groningen and elsewhere have recognized 44 new ultra-compact dwarf galaxies (UCDs). The newly discovered objects most certainly belong to the Fornax Cluster. The invention is reported in a paper revealed March 31 on the arXiv pre-print server.
UCDs are very compact galaxies with excessive stellar populations, containing about 100 million stars. They show plenty, colours and metallicities between these of globular clusters and early-type dwarf galaxies. These ultra-compact stellar methods may present necessary insights on the formation and evolution of galaxies within the universe.
Situated some 65 million gentle years away from the Earth, the Fornax Cluster is the second-richest cluster of galaxies close by. As a result of its comparatively shut proximity, it’s a worthwhile supply of details about galaxy clusters generally. Earlier observations of Fornax Cluster have detected 61 member UCDs in whole.
Now, a gaggle of astronomers led by Teymoor Saifollahi of the College of Groningen, the Netherlands, studies the discovering of dozens of latest potential UCDs which may be related to the Fornax Cluster. By analyzing the information from the Fornax Deep Survey (FDS), Vista Hemisphere Survey (VHS) and archival datasets from the Seen and Infrared Survey Telescope for Astronomy (VISTA), they recognized 44 candidate UCDs within the outskirts of this cluster.
“With the deep optical photos of the Fornax Deep Survey, mixed with public near-infrared knowledge, we revisit the UCD inhabitants of the Fornax cluster and seek for UCD candidates, for the primary time, systematically, out to the virial radius of the galaxy cluster,” the researchers wrote within the paper.
The group initially chosen 220 UCD candidates, and from this broad pattern, they selected 44 which have a better likelihood of being actual UCDs. Virtually all the newly detected UCD candidates are situated exterior the core of the Fornax Cluster (greater than 1,170 gentle years away from the cluster’s heart).
In accordance with the paper, virtually half of the newfound ultra-compact dwarf galaxies within the outskirts of the Fornax Cluster seem like intra-cluster UCDs, additional away than 650,000 gentle years from any galaxy on this cluster brighter than -18 magazine. The astronomers famous that this group of UCDs could also be fashioned in low-density environments and signify in-falling UCD populations into the cluster.
The research additionally recognized two over-densities of UCDs exterior the core of the Fornax Cluster within the northern and western sides, which seem to overlap the enhancements within the densities of dwarf galaxies on this cluster. This discovering means that the inhabitants of UCDs comply with the dwarf galaxies within the Fornax Cluster and should kind in low-density, pre-processed group environments, what challenges our present fashions of UCD formation.
The authors of the paper added that follow-up spectroscopy and radial velocity research are required with a purpose to verify the membership of the brand new UCD candidates. Such measurements would additionally shed extra gentle on the origin of those UCDs.
Galactic census reveals origin of most ‘excessive’ galaxies
Extremely-compact dwarfs past the centre of the Fornax galaxy cluster: Hints of UCD formation in low-density environments, arXiv:2104.00004 [astro-ph.GA] arxiv.org/abs/2104.00004
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Dozens of ultra-compact dwarf galaxies detected (2021, April 8)
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