Abstract
We have used the Very Large Array to search for ‘‘21-cm’’ narrow-band signals from neutral hydrogen at redshift Z=3.4. We detect absorption at Z=3.3968±0.0004 against a radio source that has been previously identified with a ‘‘normal’’ galaxy at Z=3.395±0.005. We detect emission at Z=3.3970±0.0003 separated from the absorption by 33’ (7–24 Mpc, depending on the cosmological model). This narrow-band emission signal is due to about 3× of neutral hydrogen as expected from a protocluster of galaxies. We identify it as the first example of a Zel’dovich ‘‘pancake.’’
- Received 14 August 1991
DOI:https://doi.org/10.1103/PhysRevLett.67.3328
©1991 American Physical Society