The Impact of Stochastic Attenuation on Photometric Redshift Estimates
  We model the attenuation due to HI along a random line of sight (LOS) using differential distribution functions constrained from observations (Kim et al. 97) in a Monte Carlo fashion (Bershady et al. 99) as described in Tepper Garcia & Fritze-v.A. (in prep.). We generate an ensemble of thousands of lines of sight out to a given redshift z, each of them containing a random absorber population. For each LOS we calculate an absorption mask, i.e. we compute the photoelectric and Lyman-Series line absorption (as yet just for the first five Lyman transitions) caused by each absorber for a flat input spectrum, modeling line profiles as in Tepper Garcia 2006. We compute model galaxy spectra corresponding to a CSFR for redshifts in the range 0.0 < z < 4.5 using the Evolutionary Synthesis code GALEV (Bicker et al. 2004). For a given redshift, we multiply each of the masks with our input spectrum and thus obtain an ensemble of an equal number of attenuated spectra. For each of these we compute a SED in the Johnson system. Using AnalySED (Anders et al. 2006) and a set of template SEDs that include only the mean attenuation (Madau 95) for every redshift, we determine to which extent the redshifts of our simulated spectral energy distributions are recovered. 
Thorsten Tepper Garc\'ia (Institut f\"ur Astrophysik G\"ottingen), Uta   Fritze-von Alvensleben (Centre for Astrophysics Res...