Detection of a Large Population of Ultradiffuse Galaxies in Massive Galaxy Clusters: Abell S1063 and Abell 2744

Journal Article · Tue Aug 01 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA78FB· OSTI ID:22875959

Lee, Myung Gyoon; Kang, Jisu; Lee, Jeong Hwan ^[1]

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1. Astronomy Program, Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul 08826 (Korea, Republic of)

We present the detection of a large population of ultradiffuse galaxies (UDGs) in two massive galaxy clusters, Abell S1063 at z = 0.348 and Abell 2744 at z = 0.308, based on F814W and F105W images in the Hubble Frontier Fields Program. We find 47 and 40 UDGs in Abell S1063 and Abell 2744, respectively. Color–magnitude diagrams of the UDGs show that they are mostly located at the faint end of the red sequence. From the comparison with simple stellar population models, we estimate their stellar mass to range from 10{sup 8} to 10{sup 9} M {sub ⊙}. Radial number density profiles of the UDGs show a turnover or a flattening in the central region at r < 100 kpc. We estimate the total masses of the UDGs using the galaxy scaling relations. A majority of the UDGs have total masses M {sub 200} = 10{sup 10}–10{sup 11} M {sub ⊙}, and only a few of them have total masses M {sub 200} = 10{sup 11}–10{sup 12} M {sub ⊙}. The total number of UDGs within the virial radius is estimated to be N(UDG) = 770 ± 114 for Abell S1063 and N(UDG) = 814 ± 122 for Abell 2744. Combining these results with data in the literature, we fit the relation between the total numbers of UDGs and the masses of their host systems for M {sub 200} > 10{sup 13} M {sub ⊙} with a power law, N(UDG) = M{sub 200}{sup 1.05±0.09}. These results suggest that a majority of the UDGs have a dwarf galaxy origin, while only a small number of the UDGs are massive L* galaxies that failed to form a normal population of stars.

• OSTI ID: 22875959
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 844; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPARATIVE EVALUATIONS
DENSITY
DETECTION
GALACTIC EVOLUTION
GALAXIES
GALAXY CLUSTERS
MASS
STARS