1996/03/17 by Patrick Petitjean, P. Petitjean, E. Pecontal +5 · 59 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Nebula #OVV quasar #Physics #Quasar #Redshift #Spectral line #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1038/380411a0
published in Nature 380(6573), 411-413 (Nature Portfolio) · 8 pages, 4 figures, plain LaTeX. Accepted for publication in Nature
arxiv created 1996/03/17 · openalex publication_date 1996/04/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
There is a growing consensus that the emergence of quasars at high redshifts is related to the onset of galaxy formation, suggesting that the detection of concentrations of gas accompanying such quasars should provide clues about the early history of galaxies. Quasar companions have been recently identified at redshifts up to z ≈ 3. Here we report observations of Lyman-α emission (a tracer of ionised hydrogen) from the companion to a quasar at z=4.702, corresponding to a time when the Universe was less than ten per cent of its present age. We argue that most of the emission arises in a gaseous nebula that has been photoionised by the quasar, but an additional component of continuum light -perhaps quasar light scattered from dust in the companion body, or emission from young stars within the nebula- appears necessary to explain the observations. These observations may be indicative of the first stages in the assembly of galaxy-sized structures.