ALMA detects neutral gas in galaxies 700M years after the Big Bang

Using the ALMA array in Chile, an international team detected neutral gas in four galaxies at redshifts z = 6.58–7.68, or 700–850 million years after the Big Bang. The [O I] 145 µm line confirms the gas is largely non-ionized, and the galaxies show denser, more compact star formation than present-day ones.

• ALMA detected the [O I] 145 µm line in four galaxies at z = 6.58–7.68
• Little to no ionized gas [N II] 205 µm was found, confirming neutral gas
• Stars in these galaxies were more compact and densely packed than today's
• Results were compared with JWST data and published in The Astronomical Journal