2016/10/31 by Javier Román, Ignacio Trujillo · 209 citations
Physics and Astronomy · #Accretion (finance) #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Physics #Population #Star formation #Stellar mass #Stellar, planetary, and galactic studies #Surface brightness #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stx694
published in Monthly Notices of the Royal Astronomical Society 468(4), 4039-4047 (Oxford University Press) · Accepted, matching the published version. Additional information about UDGs spectra
openalex created_date 2016/11/04 · openalex publication_date 2017/03/20 · arxiv created 2017/04/10 · arxiv updated 2017/04/12 · openalex updated_date 2026/08/05
We identify six ultra-diffuse galaxies (UDGs) outside clusters in three nearby isolated groups (0.014 < z < 0.026) using very deep imaging in three different Sloan Digital Sky Survey filters (g, r and i bands) from the IAC Stripe 82 Legacy Project. By comparing with the abundance of UDGs in rich galaxy clusters, we find that the density of UDGs (i.e. the number per unit mass of the host structure where they are located) decreases towards the most massive systems. This is compatible with a scenario where UDGs are formed preferentially outside clusters. In the periphery (D > 250 kpc) of our three groups, we identify a population of potential UDG progenitors (two of them confirmed spectroscopically). These progenitors have similar masses, shapes and sizes but are bluer, g − i ∼ 0.45 [and for this reason brighter, μg(0) < 24 mag arcsec−2] than traditional UDGs (g − i ∼ 0.76). Passive evolution of these progenitors will transform them into regular [i.e. μg(0) > 24 mag arcsec−2] UDGs after ∼6 Gyr. If confirmed, our observations support a scenario where UDGs are old, extended, low surface brightness dwarf galaxies (M⋆ ∼ 108 M⊙) born in the field, are later processed in groups and, ultimately, infall into galaxy clusters by group accretion.