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Title: The Discovery of Lensed Radio and X-ray Sources Behind the Frontier Fields Cluster MACS J0717.5+3745 with the JVLA and Chandra

We report on high-resolution JVLA and Chandra observations of the Hubble Space Telescope (HST) Frontier Cluster MACS J0717.5+3745. MACS J0717.5+3745 offers the largest contiguous magnified area of any known cluster, making it a promising target to search for lensed radio and X-ray sources. With the high-resolution 1.0–6.5 GHz JVLA imaging in A and B configuration, we detect a total of 51 compact radio sources within the area covered by the HST imaging. Within this sample, we find seven lensed sources with amplification factors larger than two. None of these sources are identified as multiply lensed. Based on the radio luminosities, the majority of these sources are likely star-forming galaxies with star-formation rates (SFRs) of 10–50 M yr -1 located at 1≲ z ≲ 2. Two of the lensed radio sources are also detected in the Chandra image of the cluster. These two sources are likely active galactic nuclei, given their 2–10 keV X-ray luminosities of ~ 10 43-44 erg s -1. From the derived radio luminosity function, we find evidence for an increase in the number density of radio sources at 0.6 < z < 2.0, compared to a z < 0.3 sample. Lastly, our observations indicate that deepmore » radio imaging of lensing clusters can be used to study star-forming galaxies, with SFRs as low as ~10M yr -1, at the peak of cosmic star formation history.« less
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  1. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
  2. Univ. of Hamburg (Germany). Hamburger Sternwarte
  3. Naval Research Lab. (NRL), Washington, DC (United States)
  4. Max Planck Society, Garching (Germany). Max Planck Inst. for Astrophysics; Space Research Inst., Moscow (Russia)
  5. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  6. Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy
  7. Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences
  8. National Radio Astronomy Observatory, Charlottesville, VA (United States)
  9. Univ. of Oxford (United Kingdom). Dept. of Physics
  10. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Johns Hopkins Univ., Baltimore, MD (United States). Department of Physics and Astronomy
  11. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Univ. of Western Australia, Crawley WA (Australia). International Centre for Radio Astronomy Research (ICRAR)
  12. Univ. degli Studi di Ferrara (Italy). Dipartimento di Fisica e Scienze della Terra
  13. Univ. of Hull, Hull (United Kingdom). E.A. Milne Centre for Astrophysics, Dept. of Physics & Mathematics
  14. California Inst. of Technology (CalTech), Pasadena, CA (United States). Cahill Center for Astronomy and Astrophysics
  15. Academia Sinica, Taipei (Taiwan). Inst. of Astronomy and Astrophysics
Publication Date:
Report Number(s):
Journal ID: ISSN 1538-4357
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 817; Journal Issue: 2; Journal ID: ISSN 1538-4357
Institute of Physics (IOP)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; galaxies: clusters: individual (MACS J0717.5+3745); gravitational lensing: strong; radio continuum: galaxies
OSTI Identifier: