* Astronomy

Title: Keck Observations of the Most Distant Galaxy: 8C1435+63 at z=4.25
Authors: Hyron Spinrad, Arjun Dey, James R. Graham (U.C.Berkeley)
(1 Nov 1994)

We report on Keck observations and confirm the redshift of the most distant galaxy known: 8C1435+63 at z=4.25. The spectrum shows a strong Ly \alpha line, a Ly \alpha forest continuum break and a continuum break at \lambda_{rest}=912 \AA. The Ly \alpha emission is spatially extended and roughly aligned with the radio source. The galaxy shows a double structure in the I-band (\lambda_{rest} ~1500\AA) which is aligned with the radio axis; the two I-band components spatially coincide with the nuclear and southern radio components. Some fraction of the I band emission could be due to a nonthermal process such as inverse compton scattering. In the K-band (\lambda_{rest} ~4200\AA), which may be dominated by starlight, the galaxy has a very low surface brightness, diffuse morphology. The K morphology shows little relationship to the radio source structure, although the major axis of the K emission is elongated roughly in the direction of the radio source axis. The galaxian continuum is very red (I-K>4) and if the K continuum is due to starlight, implies a formation redshift of z_f > 5. We speculate that this galaxy may be the progenitor of a present day cD galaxy.

Read more (75kb, PDF)