The importance of nebular emission for SED modeling of distant
  star-forming galaxies
  We highlight and discuss the importance of accounting for nebular emission in
the SEDs of high redshift galaxies, as lines and continuum emission can
contribute significantly or subtly to broad-band photometry. Physical
parameters such as the galaxy age, mass, star-formation rate, dust attenuation
and others inferred from SED fits can be affected to different extent by the
treatment of nebular emission.
  We analyse a large sample of Lyman break galaxies from z~3-6, and show some
main results illustrating e.g. the importance of nebular emission for
determinations of the mass-SFR relation, attenuation and age. We suggest that a
fairly large scatter in such relations could be intrinsic. We find that the
majority of objects (~60-70%) is better fit with SEDs accounting for nebular
emission; the remaining galaxies are found to show relatively weak or no
emission lines. Our modeling, and supporting empirical evidence, suggests the
existence of two categories of galaxies, "starbursts" and "post-starbursts"
(lower SFR and older galaxies) among the LBG population, and relatively short
star-formation timescales.
