1998/01/29 by V. Le Brun, Brun, V. Le, J. Bergeron +1
Physics and Astronomy · #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Nuclear physics research studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9801302
accepted for publication in A&A main journal. 12 pages, 16 figures, uses aa.cls
arxiv created 1998/01/29 · openalex publication_date 1998/01/29 · arxiv updated 2009/12/01 · openalex created_date 2024/04/11 · openalex updated_date 2026/07/28
We present further observational results on our Lya-only absorber identification project at low and intermediate redshifts. We combine CFHT/MOS imaging and spectroscopic observations of 25 galaxies in the field of the quasar 3C286 (ze = 0.849) with HST/FOS spectrum of the quasar between 1600 and 3000 A and HST/WFPC2 high spatial resolution imaging of some galaxies. Our results confirm our first conclusions on the nature of the intermediate redshift Ly-alpha forest absorbers. A small fraction of them is tightly linked to galaxies, and most probably arise in the external parts of giant halos (R~200 kpc with H0=50 km/s/Mpc) around fairly luminous galaxies (MAB(B) < -19) of various spectral and morphological types, as shown by HST imaging of these objects. Most of the absorbing clouds appear to be only ``associated'' with galaxies, in the sense that they could trace the gaseous filaments or sheets of large-scale structures. Thus, as expected from a sample tracing large scale structures, these galaxies have various spectral types. We also find that groups of galaxies have always at least one associated Ly-alpha absorption line.