RELICS: Strong-lensing Analysis of the Massive Clusters MACS J0308.9+2645 and PLCK G171.9-40.7

Ana Acebron, Nathália Cibirka, Adi Zitrin, Dan Coe, Irene Agulli, Keren Sharon, Maruša Bradač, Brenda Frye, Rachael C. Livermore, Guillaume Mahler, Brett Salmon, Keiichi Umetsu, Larry Bradley, Felipe Andrade-Santos, Roberto Avila, Daniela Carrasco, Catherine Cerny, Nicole G. Czakon, William A. Dawson, Austin T. HoagKuang Han Huang, Traci L. Johnson, Christine Jones, Shotaro Kikuchihara, Daniel Lam, Lorenzo Lovisari, Ramesh Mainali, Pascal A. Oesch, Sara Ogaz, Masami Ouchi, Matthew Past, Rachel Paterno-Mahler, Avery Peterson, Russell E. Ryan, Irene Sendra-Server, Daniel P. Stark, Victoria Strait, Sune Toft, Michele Trenti, Benedetta Vulcani

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Strong gravitational lensing by galaxy clusters has become a powerful tool for probing the high-redshift universe, magnifying distant and faint background galaxies. Reliable strong-lensing (SL) models are crucial for determining the intrinsic properties of distant, magnified sources and for constructing their luminosity function. We present here the first SL analysis of MACS J0308.9+2645 and PLCK G171.9-40.7, two massive galaxy clusters imaged with the Hubble Space Telescope, in the framework of the Reionization Lensing Cluster Survey (RELICS). We use the light-traces-mass modeling technique to uncover sets of multiply imaged galaxies and constrain the mass distribution of the clusters. Our SL analysis reveals that both clusters have particularly large Einstein radii (θ E > 30″ for a source redshift of z s = 2), providing fairly large areas with high magnifications, useful for high-redshift galaxy searches (∼2 arcmin2 with μ > 5 to ∼1 arcmin2 with μ > 10, similar to a typical Hubble Frontier Fields cluster). We also find that MACS J0308.9+2645 hosts a promising, apparently bright (J ∼ 23.2-24.6 AB), multiply imaged high-redshift candidate at z ∼ 6.4. These images are among the brightest high-redshift candidates found in RELICS. Our mass models, including magnification maps, are made publicly available for the community through the Mikulski Archive for Space Telescopes.

Original languageEnglish
Article number42
JournalAstrophysical Journal
Issue number1
StatePublished - 1 May 2018


  • galaxies: clusters: individual (MACS J0308.9+2645, PLCK G171.9-40.7)
  • gravitational lensing: strong

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'RELICS: Strong-lensing Analysis of the Massive Clusters MACS J0308.9+2645 and PLCK G171.9-40.7'. Together they form a unique fingerprint.

Cite this