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The Impact of Stochastic Attenuation on Photometric Redshift Estimates

Thorsten Tepper García·Uta Fritze-von Alvensleben
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Abstract

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.

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Thorsten Tepper García, Uta Fritze-von Alvensleben. 2006-09-13. The Impact of Stochastic Attenuation on Photometric Redshift Estimates. https://doi.org/10.1017/s174392130601060x

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