2021/09/24 by F. Marleau, Francine R. Marleau, Rebecca Habas +17 · 64 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Physics #Red shift #astro-ph.GA
paper · pdf · doi:10.1051/0004-6361/202141432
published in Astronomy and Astrophysics 654, A105 (EDP Sciences) · 32 pages, 25 figures, 3 tables, accepted in A&A; All data including images may be queried from the MATLAS web project: http://obas-matlas.u-strasbg.fr/WP/?page_id=825
openalex publication_date 2021/09/24 · arxiv created 2021/09/27 · arxiv updated 2021/10/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Recent advances in deep dedicated imaging surveys over the past decade have uncovered a surprisingly large number of extremely faint low surface brightness galaxies with large physical sizes called ultra diffuse galaxies (UDGs) in clusters and, more recently, in lower density environments. As part of the Mass Assembly of early-Type GaLAxies with their fine Structures (MATLAS) survey, a deep imaging large program at the Canada-France-Hawaii Telescope (CFHT), our team has identified 2210 dwarf galaxies, 59 (∼3%) of which qualify as UDGs. Averaging over the survey area, we find ∼0.4 UDG per square degree. They are found in a range of low to moderate density environments, although 61% of the sample fall within the virial radii of groups. Based on a detailed analysis of their photometric and structural properties, we find that the MATLAS UDGs do not show significant differences from the traditional dwarfs, except from the predefined size and surface brightness cut. Their median color is as red as the one measured in galaxy clusters, albeit with a narrower color range. The majority of the UDGs are visually classified as dwarf ellipticals with log stellar masses of ∼6.5 − 8.7. The fraction of nucleated UDGs (∼34%) is roughly the same as the nucleated fraction of the traditional dwarfs. Only five (∼8%) UDGs show signs of tidal disruption and only two are tidal dwarf galaxy candidates. A study of globular cluster (GC) candidates selected in the CFHT images finds no evidence of a higher GC specific frequency S N for UDGs than for classical dwarfs, contrary to what is found in most clusters. The UDG halo-to-stellar mass ratio distribution, as estimated from the GC counts, peaks at roughly the same value as for the traditional dwarfs, but spans the smaller range of ∼10 − 2000. We interpret these results to mean that the large majority of the field-to-group UDGs do not have a different formation scenario than traditional dwarfs.