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Title: M32 analogs? A population of massive ultra-compact dwarf and compact elliptical galaxies in intermediate-redshift clusters

Here, we report the discovery of relatively massive, M32-like ultra compact dwarf (UCD) and compact elliptical (CE) galaxy candidates in $$0.2\lt z\lt 0.6$$ massive galaxy clusters imaged by the Cluster Lensing And Supernova survey with Hubble (CLASH) survey. Examining the nearly unresolved objects in the survey, we identify a sample of compact objects concentrated around the cluster central galaxies with colors similar to cluster red sequence galaxies. Their colors and magnitudes suggest stellar masses around $${10}^{9}{M}_{\odot }$$. More than half of these galaxies have half-light radii smaller than 200 pc, falling into the category of massive UCDs and CEs, with properties similar to M32. The properties are consistent with a tidal stripping origin, but we cannot rule out the possibility that they are early-formed compact objects trapped in massive dark matter halos. The 17 CLASH clusters studied in this work on average contain 2.7 of these objects in their central 0.3 Mpc and 0.6 in their central 50 kpc. Our study demonstrates the possibility of statistically characterizing UCDs/CEs with a large set of uniform imaging survey data.
 [1] ; ORCiD logo [2]
  1. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Univ. of Michigan, Ann Arbor, MI (United States)
  2. Univ. of Michigan, Ann Arbor, MI (United States)
Publication Date:
Report Number(s):
arXiv:1610.06174; FERMILAB-PUB-16-450-AE
Journal ID: ISSN 2041-8213; 1594857
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal. Letters
Additional Journal Information:
Journal Volume: 835; Journal Issue: 1; Journal ID: ISSN 2041-8213
Institute of Physics (IOP)
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; galaxies: clusters: general; galaxies: evolution
OSTI Identifier: