ZEN2: A narrow J-band search for z~9 Lya emitting galaxies directed towards three lensing clusters

TL;DR

The ZEN2 survey used narrow J-band imaging towards lensing clusters to search for z~9 Lya emitting galaxies but found no candidates, providing constraints on their abundance and informing future detection prospects.

Contribution

This study presents the first deep narrow J-band survey targeting z~9 galaxies using lensing clusters, setting upper limits on their luminosity function.

Findings

No z~9 Lya emitters detected above flux limit

Survey sampled a volume of ~1700 Mpc3 at z~9

Results constrain the abundance of high-redshift Lya emitters

Abstract

We present the results of a continuing survey to detect Lya emitting galaxies at redshifts z~9: the ZEN ("z equals nine'') survey. We have obtained deep VLT/ISAAC observations in the narrow J-band filter NB119 directed towards three massive lensing clusters: Abell clusters 1689, 1835, and 114. The foreground clusters provide a magnified view of the distant universe and permit a sensitive test for the presence of very high-redshift galaxies. We search for z~9 Lya emitting galaxies displaying a significant narrow-band excess relative to accompanying J-band observations that remain undetected in HST/ACS optical images of each field. No sources consistent with this criterion are detected above the unlensed 90% point-source flux limit of the narrow-band image, F_NB=3.7e-18 ergs/s/cm2. To date, the total coverage of the ZEN survey has sampled a volume at z~9 of approximately 1700 co-moving Mpc3 to a Lya emission luminosity of 1e43 erg/s. We conclude by considering the prospects for detecting z~9 Lya emitting galaxies in light of both observed galaxy properties at z<7 and simulated populations at z>7.