Yashar D. Hezaveh, Daniel P. Marrone, Gilbert P. Holder
We address two selection effects that operate on samples of gravitationally lensed dusty galaxies identified in millimeter and submillimeter-wavelength surveys. First, we point out the existence of a "size bias" in such samples: due to finite source effects, sources with higher observed fluxes are increasingly biased towards more compact objects. Second, we examine the effect of differential lensing in individual lens systems by modelling each source as a compact core embedded in an extended diffuse halo. Considering the ratio of magnifications in these two components, we find that at high overall magnifications the compact component is amplified by a much larger factor than the diffuse component, but at intermediate magnifications (~10) the probability of a larger magnification for the extended region is higher. Lens models determined from resolved imaging data, rather than the typically unresolved discovery images, are crucial to correct for this effect.
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http://arxiv.org/abs/1203.3267
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