JWST measures a redshift beyond 10 for a galaxy candidate

From photometry to spectrum

In 2025, a COSMOS-Web study selected CW-LRD-z10 from combined NIRCam and MIRI images, estimating a photometric redshift of 10.5 (+0.7/−0.6). Its authors said deeper spectroscopy was still needed to confirm the source’s redshift and nature.[2]

An arXiv v1 submitted on 30 October 2026 reports an EMBER-program JWST/NIRSpec spectrum. The authors’ best fit is z=10.361 (+0.003/−0.002), largely driven by tentative lines and the Lyman-alpha break. Masking other tentative-line regions while retaining Ly-alpha gives less precise, consistent estimates around z=10.3–10.4.[1]

Distance, label and engine

Redshift tracks cosmic expansion’s stretch of light; it does not identify the source. The authors call CW-LRD-z10 the first z>10 little red dot candidate with a spectroscopic redshift, but say its class remains uncertain: this spectrum does not cover Hα and Hβ. Detected lines are tentative (signal-to-noise 2–4); their ratios do not rule out star formation, and an obscured active galactic nucleus remains possible. The physical power source remains unresolved.[1]