2025/02/14 by N. J. Adams, Adams, N. J., Duncan Austin +17 · 4 citations
Physics and Astronomy · Engineering · #Astronomy and Astrophysical Research #Astronomical Observations and Instrumentation #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2502.10282
New, ultra-deep medium-width photometric coverage with JWST's NIRCam instrument provides the potential for much improved photo-z reliability at high redshifts. In this study, we conduct a systematic analysis of the JADES Origins Field, which contains 14 broad- and medium-width near-infrared bands, to assess the benefits of medium band photometry on high-z completeness and contamination rates. Using imaging reaching AB mag 29.8-30.35 depth, we test how high-z selections differ when images are artificially degraded or bands are removed. In parallel, the same experiments are conducted on simulated catalogues from the JAGUAR semi-analytic model to examine if observations can be replicated. We find sample completeness is high (80%+) and contamination low (<4%) when in the 10σ+ regime, even without the use of any medium-width bands. The addition of medium-width bands leads to increases in completeness (∼10%) but multiple bands are required to improve contamination rates due to the small redshift ranges over which they probe strong emission lines. Incidents of Balmer-Lyman degeneracy increase in the 5-7σ regime and this can be replicated in both simulated catalogues and degraded real data. We measure the faint-end of the UV LF at 8.5