Abstract
We present a ground-based near-infrared search for lensed supernovae behind
the massive cluster Abell 1689 at z=0.18, one of the most powerful
gravitational telescopes that nature provides. 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. Our search resulted
in the discovery of five high-redshift, $0.671<z<1.703$, photometrically
classified core-collapse supernovae with magnifications in the range $\Delta m$
= $-0.31$ to $-1.58$ mag, as calculated from lensing models in the literature.
Thanks to the power of the lensing cluster, the survey had the sensitivity to
detect supernovae up to very high-redshifts, $z$$\sim$$3$, albeit for a limited
region of space. We present a study of the core-collapse supernova rates for
$0.4z< 2.9$, and find good agreement with both previous estimates, and the
predictions from the star formation history. During our survey, we also
discovered 2 type Ia supernovae in A1689 cluster members, which allowed us to
determine the cluster Ia rate to be $0.14^+0.19_-0.09\pm0.01$
$SNuB$$\,h^2$ (SNuB$10^-12 \,SNe \, L^-1_ødot,B
yr^-1$). The cluster rate normalized by the stellar mass is
$0.10^+0.13_-0.06\pm0.02$ in $SNuM$$\,h^2$ (SNuM$10^-12
\,SNe \, M^-1_ødot yr^-1$). Furthermore, we explore the optimal
future survey for improving the core-collapse supernova rate measurements at
$z\gtrsim2$ using gravitational telescopes, as well as for the detections with
multiply lensed images, and find that the planned WFIRST space mission has
excellent prospects. 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.
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