The Lyman alpha reference sample: Extended Lyman alpha halos produced at low dust content

Research output: Contribution to journalJournal articlepeer-review

  • M. Hayes
  • G. Östlin
  • D. Schaerer
  • A. Verhamme
  • J.M. Mas-Hesse
  • A. Adamo
  • H. Atek
  • J.M. Cannon
  • F. Duval
  • L. Guaita
  • E.C. Herenz
  • D. Kunth
  • Laursen, Peter
  • J. Melinder
  • I. Orlitová
  • H. Otí-Floranes
  • A. Sandberg
We report on new imaging observations of the Lyman alpha emission line (Lyα), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028 <z <0.18 in continuum-subtracted Lyα, Hα, and the far ultraviolet continuum. We show that Lyα is emitted on scales that systematically exceed those of the massive stellar population and recombination nebulae: as measured by the Petrosian 20% radius, R , Lyα radii are larger than those of Hα by factors ranging from 1 to 3.6, with an average of 2.4. The average ratio of Lyα-to-FUV radii is 2.9. This suggests that much of the Lyα light is pushed to large radii by resonance scattering. Defining the Relative Petrosian Extension of Lyα compared to Hα, ξ = R /R , we find ξ to be uncorrelated with total Lyα luminosity. However, ξ is strongly correlated with quantities that scale with dust content, in the sense that a low dust abundance is a necessary requirement (although not the only one) in order to spread Lyα photons throughout the interstellar medium and drive a large extended Lyα halo.
Original languageEnglish
Article numberL27
JournalThe Astrophysical Journal Letters
Volume765
Issue number2
ISSN2041-8205
DOIs
Publication statusPublished - 10 Mar 2013

ID: 91328649