Scientific Motivation

Recent JWST discoveries of galaxies at z ≳ 10–14 and abundant faint AGN candidates at high redshift highlight a rapidly emerging picture of early structure formation. The next challenge is to move beyond the bright tail of these populations and access their intrinsically faint progenitors, where the physics of first light, early metal enrichment, and compact object growth are most directly encoded.

VENUS addresses this by dramatically expanding the highly magnified area surveyed with JWST. Strong lensing boosts the apparent brightness and spatial resolution of distant sources, enabling spectroscopy and resolved studies that would be infeasible in blank-field surveys. With uniform multi-band imaging and targeted follow-up, VENUS constrains the onset of star formation and the faint-end of the UV luminosity function, resolves stellar populations down to star-cluster scales, and enables a systematic census of low-mass black holes and early time-domain phenomena in the first billion years.

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Observational Setup

VENUS is a two-epoch program optimized for discovery, uniformity, and rapid community value:

• Epoch 1 (Imaging Treasury): Uniform NIRCam 10-filter imaging over 60 well-studied massive lensing clusters, covering a total area of ~0.16 deg² to a typical depth of 5σ ≈ 28 mag. These data substantially widen the JWST-observed highly magnified area and enable statistically powerful samples of lensed high-redshift sources.
• Epoch 2 (Follow-up + Time Domain): In the 10 best-selected clusters, VENUS adds NIRSpec/MSA　prism+G395M spectroscopy for key high-redshift candidates, together with multi-epoch NIRCam 2-filter imaging to open a time-domain lensing window for rare transients and variability studies.

Official program information for VENUS is available from STScI: Program Information, including the downloadable APT materials.