2006/11/30 by Sebastiano Cantalupo, Simon J. Lilly, Cristiano Porciani · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/510883
published as Astrophys.J.657:135-144,2007 · 10 pages, 4 figures.Update to match the version published on ApJ 657, 135, 2007 March 1
arxiv created 2007/02/28 · openalex publication_date 2007/03/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We report the results of a survey for fluorescent Lyα emission carried out in the field surrounding the z = 3.1 quasar QSO 0420-388 using the Focal Reducer/Low Dispersion Spectrograph 2 (FORS2) instrument on the Very Large Telescope (VLT). We first review the properties expected for fluorescent Lyα emitters, compared with those of other nonfluorescent Lyα emitters. Our observational search detected 13 Lyα sources sparsely sampling a volume of ~14,000 comoving Mpc 3 around the quasar. The properties of these in terms of (1) the line equivalent width, (2) the line profile, and (3) the value of the surface brightness related to the distance from the quasar all suggest that several of these may be plausibly fluorescent. Moreover, their number is in good agreement with the expectation from theoretical models. One of the best candidates for fluorescence is sufficiently far behind QSO 0420-388 that it would imply that the quasar has been active for (at least) ~60 Myr. Further studies on such objects will give information about protogalactic clouds and on the radiative history (and beaming) of the high-redshift quasars.