High-redshift supernova rates measured with the gravitational telescope A 1689^⋆,⋆⋆

¹ Oskar Klein Centre, Physics Department, Stockholm University, 106 91 Stockholm, Sweden
e-mail: tpetr@fysik.su.se
² Physics Department, Stockholm University, 106 91 Stockholm, Sweden
³ NRC Herzberg Institute for Astrophysics, 5071 West Saanich Road, Victoria V9E 2E7, British Columbia, Canada
⁴ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 7610001 Rehovot, Israel
⁵ Australian Astronomical Observatory, PO Box 915, 1670 North Ryde, Australia
⁶ Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians Universitaet München, Scheinerstr. 1, 81679 Muenchen, Germany
⁷ Excellence Cluster Universe, Boltzmannstr. 2, 85748 Garching, Germany
⁸ Univ. Lyon, Univ. Lyon1, Ens de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR 5574, 69230 Saint-Genis-Laval, France
⁹ Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029, Blindern, 0315 Oslo, Norway
¹⁰ Laboratoire d’Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
¹¹ Laboratoire d’Astrophysique de Marseille, UMR 6610, CNRS-Université de Provence, 38 rue Frédéric Joliot-Curie, 13388 Marseille Cedex 13, France
¹² Institut für Physik, Humboldt-Universitat zu Berlin, Newtonstr. 15, 12489 Berlin, Germany
¹³ Department of Physics, Chemistry and Biology, IFM, Linköping University, 581 83 Linköping, Sweden

Received: 13 May 2016
Accepted: 5 July 2016

Abstract

Aims. We present a ground-based, near-infrared search for lensed supernovae behind the massive cluster Abell 1689 at z = 0.18, which is one of the most powerful gravitational telescopes that nature provides.

Methods. Our survey was based on multi-epoch J-band observations with the HAWK-I instrument on VLT, with supporting optical data from the Nordic Optical Telescope.

Results. Our search resulted in the discovery of five photometrically classified, core-collapse supernovae with high redshifts of 0.671 < z < 1.703 and magnifications in the range Δm = − 0.31 to −1.58 mag, as calculated from lensing models in the literature. Owing to the power of the lensing cluster, the survey had the sensitivity to detect supernovae up to very high redshifts, z~3, albeit for a limited region of space. We present a study of the core-collapse supernova rates for 0.4 ≤ z< 2.9, and find good agreement with previous estimates and predictions from star formation history. During our survey, we also discovered two Type Ia supernovae in A 1689 cluster members, which allowed us to determine the cluster Ia rate to be 0.14^+0.19_-0.09±0.01SNuB h² (SNuB≡10^-12SNe L^-1_⊙,B yr^-1), where the error bars indicate 1σ confidence intervals, statistical and systematic, respectively. The cluster rate normalized by the stellar mass is 0.10^+0.13_-0.096±0.02 in SNuM h² (SNuM ≡10^-12SNe M^-1_⊙ yr^-1). Furthermore, we explore the optimal future survey for improving the core-collapse supernova rate measurements at z ≳ 2 using gravitational telescopes, and for detections with multiply lensed images, and we find that the planned WFIRST space mission has excellent prospects.

Conclusions. Massive clusters can be used as gravitational telescopes to significantly expand the survey range of supernova searches, with important implications for the study of the high-z transient Universe.