RELICS: Reionization Lensing Cluster Survey

Dan Coe, Brett Salmon, Maruša Bradač, Larry D. Bradley, Keren Sharon, Adi Zitrin, Ana Acebron, Catherine Cerny, Nathália Cibirka, Victoria Strait, Rachel Paterno-Mahler, Guillaume Mahler, Roberto J. Avila, Sara Ogaz, Kuang Han Huang, Debora Pelliccia, Daniel P. Stark, Ramesh Mainali, Pascal A. Oesch, Michele TrentiDaniela Carrasco, William A. Dawson, Steven A. Rodney, Louis Gregory Strolger, Adam G. Riess, Christine Jones, Brenda L. Frye, Nicole G. Czakon, Keiichi Umetsu, Benedetta Vulcani, Or Graur, Saurabh W. Jha, Melissa L. Graham, Alberto Molino, Mario Nonino, Jens Hjorth, Jonatan Selsing, Lise Christensen, Shotaro Kikuchihara, Masami Ouchi, Masamune Oguri, Brian Welch, Brian C. Lemaux, Felipe Andrade-Santos, Austin T. Hoag, Traci L. Johnson, Avery Peterson, Matthew Past, Carter Fox, Irene Agulli, Rachael Livermore, Russell E. Ryan, Daniel Lam, Irene Sendra-Server, Sune Toft, Lorenzo Lovisari, Yuanyuan Su

Research output: Contribution to journalArticlepeer-review

88 Citations (SciVal)


Large surveys of galaxy clusters with the Hubble Space Telescope (HST) and Spitzer, including the Cluster Lensing And Supernova survey with Hubble and the Frontier Fields, have demonstrated the power of strong gravitational lensing to efficiently deliver large samples of high-redshift galaxies. We extend this strategy through a wider, shallower survey named RELICS, the Reionization Lensing Cluster Survey, described here. Our 188-orbit Hubble Treasury Program observed 41 clusters at 0.182 ≤ z ≤ 0.972 with Advanced Camera for Surveys (ACS) and WFC3/IR imaging spanning 0.4-1.7 μm. We selected 21 of the most massive clusters known based on Planck PSZ2 estimates and 20 additional clusters based on observed or inferred lensing strength. RELICS observed 46 WFC3/IR pointings (∼200 arcmin2) each with two orbits divided among four filters (F105W, F125W, F140W, and F160W) and ACS imaging as needed to achieve single-orbit depth in each of three filters (F435W, F606W, and F814W). As previously reported by Salmon et al., we discovered over 300 z ∼ 6-10 candidates, including the brightest z ∼ 6 candidates known, and the most distant spatially resolved lensed arc known at z ∼ 10. Spitzer IRAC imaging (945 hr awarded, plus 100 archival, spanning 3.0-5.0 μm) has crucially enabled us to distinguish z ∼ 10 candidates from z ∼ 2 interlopers. For each cluster, two HST observing epochs were staggered by about a month, enabling us to discover 11 supernovae, including 3 lensed supernovae, which we followed up with 20 orbits from our program. Reduced HST images, catalogs, and lens models are available on MAST, and reduced Spitzer images are available on IRSA.

Original languageEnglish
Article number85
JournalAstrophysical Journal
Issue number1
StatePublished - Oct 10 2019

Bibliographical note

Funding Information:
The RELICS Hubble Treasury Program (GO 14096) consists of observations obtained by the NASA/ESA Hubble Space Telescope (HST). HST is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under NASA contract NAS5-26555. Data from the NASA/ESA HST presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST), operated by the Space Telescope Science Institute (STScI). STScI is operated by the Association of Universities for Research in Astronomy, Inc.(AURA), under NASA contract NAS 5-26555. The HST Advanced Camera for Surveys (ACS) was developed under NASA contract NAS 5-32864. Spitzer Space Telescope data presented in this paper were obtained from the NASA/IPAC Infrared Science Archive (IRSA), operated by the Jet Propulsion Laboratory, California Institute of Technology. Spitzer and IRSA are operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. We gratefully acknowledge support from JPL for the Spitzer analysis. M.B. and V.S. also acknowledge support by NASA through ADAP grant 80NSSC18K0945, NASA/HST through HST-GO-14096, HST-GO-13666, and two awards issued by Spitzer/JPL/Caltech associated with the SRELICS-DEEP and SRELICS programs. Part of this work by W.D. was performed under the auspices of the U.S. DOE by LLNL under contract DE-AC52-07NA27344. K.U. acknowledges support from the Ministry of Science and Technology of Taiwan (grant MOST 106-2628-M-001-003-MY3) and from Academia Sinica (grant AS-IA-107-M01). O.G. is supported by an NSF Astronomy and Astrophysics Fellowship under award AST-1602595. S.A.R. was supported by NASA grant HST-GO-14208 from STScI, which is operated by Associated Universities for Research in Astronomy, Inc. (AURA), under NASA contract NAS 5-26555. A.M. acknowledges the financial support of the Brazilian funding agency FAPESP (Post-doc fellowship-process No. 2014/11806-9). J.H. was supported by a VILLUM FONDEN Investigator grant (project No. 16599). Finally, we thank our referee for detailed comments that helped us improve the manuscript.

Publisher Copyright:
© 2019. The American Astronomical Society. All rights reserved.


  • dark ages, reionization, first stars
  • dark matter
  • galaxies: clusters: general
  • galaxies: high-redshift
  • gravitational lensing: strong
  • supernovae: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'RELICS: Reionization Lensing Cluster Survey'. Together they form a unique fingerprint.

Cite this