Overview
- Kimihiko Nakajima’s team, in a Nature paper published Wednesday, reports JWST spectra of LAP1-B, a background galaxy magnified into view by the cluster MACS J0416 and seen about 800 million years after the Big Bang.
- The gas shows extreme metal poverty with oxygen at about 0.4 percent of the Sun’s level and strong high‑energy lines including triply ionized carbon that point to enrichment by the Universe’s first‑generation stars.
- JWST did not detect the galaxy’s starlight, which sets a hard upper limit of roughly 3,300 solar masses for its total stellar content.
- Broadened emission lines indicate gas moving near 58 kilometers per second, implying a total mass around ten million solar masses dominated by a dark matter halo.
- Independent astronomers call LAP1-B a compelling ‘cosmic fossil’ candidate that could link early building blocks to today’s ultra‑faint dwarf galaxies, while urging deeper JWST observations for confirmation.