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Title: RCS2 J232727.6-020437: An efficient cosmic telescope at Z = 0.6986

Here, we present a detailed gravitational lens model of the galaxy cluster RCS2 J232727.6-020437. Due to cosmological dimming of cluster members and ICL, its high redshift (z=0.6986) makes it ideal for studying background galaxies. Using new ACS and WFC3/IR HST data, we identify 16 multiple images. From MOSFIRE follow up, we identify a strong emission line in the spectrum of one multiple image, likely confirming the redshift of that system to z=2.083. With a highly magnified (μ ≳ 2) source plane area of ~ 0.7 arcmin 2 at z = 7, RCS2 J232727.6-020437 has a lensing efficiency comparable to the Hubble Frontier Fields clusters. We discover four highly magnified z ~ 7 candidate Lyman-break galaxies behind the cluster, one of which may be multiply-imaged. Correcting for magnification, we find that all four galaxies are fainter than 0.5L *. One candidate is detected at >10σ in both Spitzer/IRAC [3.6] and [4.5] channels. A spectroscopic follow-up with MOSFIRE does not result in the detection of the Lyman-alpha emission line from any of the four candidates. From the MOSFIRE spectra we place median upper limits on the Lyman-alpha flux of 5 – 14 × 10 –19 ergs –1cm –2 (5σ).
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1] ;  [4] ;  [4] ;  [6] ;  [7] ;  [8] ;  [1] ;  [9] ;  [10]
  1. Univ. of California, Davis, CA (United States)
  2. Space Telescope Science Institute, Baltimore, MD (United States)
  3. Univ. of Michigan, Ann Arbor, MI (United States)
  4. Argelander-Institut fur Astronomie, Bonn (Germany)
  5. Univ. of California, Santa Barbara, CA (United States)
  6. MMT Observatory, Tucson, AZ (United States)
  7. Aix-Marseille Univ., CNRS, LAM, Marseille (France)
  8. Stanford Univ., Stanford, CA (United States); Univ. of Copenhagen, Copenhagen (Denmark)
  9. UCLA, Los Angeles, CA (United States)
  10. Univ. of Arizona, Tucson, AZ (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1538-4357; arXiv:1503.02670
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 813; Journal Issue: 1; Journal ID: ISSN 1538-4357
Institute of Physics (IOP)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; .astrophysics; ASTRO; galaxies: clusters: individual (RCS2 J232727.6-020437); galaxies: high-redshift; gravitational lensing: strong
OSTI Identifier: