Star-forming Galactic Contrails at z=3.2 as a Source of Metal Enrichment
  and Ionizing Radiation
  A spectroscopically detected Lyman alpha emitting halo at redshift 3.216 in
the GOODS-N field is found to reside at the convergence of several Lyman alpha
filaments. HST images show that some of the filaments are inhabited by
galaxies. Several of the galaxies in the field have pronounced head-tail
structures, which are partly aligned with each other. The blue colors of most
tails suggest the presence of young stars, with the emission from at least one
of the galaxies apparently dominated by high equivalent width Lyman alpha.
Faint, more diffuse, and similarly elongated, apparently stellar features, can
be seen over an area with a linear extent of at least 90 kpc. The region within
several arcseconds of the brightest galaxy exhibits spatially extended emission
by HeII, NV and various lower ionization metal lines. The gas-dynamical
features present are strongly reminiscent of ram-pressure stripped galaxies,
including evidence for recent star formation in the stripped contrails. Spatial
gradients in the appearance of several galaxies may represent a stream of
galaxies passing from a colder to a hotter intergalactic medium. The stripping
of gas from the in-falling galaxies, in conjunction with the occurrence of star
formation and stellar feedback in the galactic contrails suggests a mechanism
for the metal enrichment of the high redshift intergalactic medium that does
not depend on long-range galactic winds, at the same time opening a path for
the escape of ionizing radiation from galaxies.
