1604.05723
ALMA imaging and gravitational lens models of South Pole Telescope-selected dusty, star-forming galaxies at high redshifts
Spilker, et al
The SPT has discovered 100 [strong-] gravitationally lensed, high-z, dusty, star-forming galaxies (DSFGs). Present 0.5" resolution 870um ALMA imaging of a sample of 47 DSFGs spanning z=1.9-5.7, and construct GL models of these sources. The visibility-based lens modeling incorporates several sources of residual interferometric calibration uncertainty, allowing us to properly account for noise in the observations. At least 70% of the sources are strongly lensed by FG galaxies (mu_870um>2), with a median magnification mu_870um=6.3, extending to mu_870um>30. Compare the intrinsic size distribution of the SL sources to a similar number of unlensed DSFGs and find no significant differences in spite of a bias between the magnification and intrinsic source size. This may indicate that the true size distribution of DSFGs is relatively narrow. Use the source sizes to constrain the wavelength at which the dust optical depth is unity and find this wavelength to be correlated with the dust temperature. This correlation leads to discrepancies in dust mass estimates of a factor of 2 compared to estimates using a single value for this wavelength. Investigate the relationship between the [CII] line and the FIR luminosity and find the the same correlation between the [CII]L_FIR ratio and Sigma_FIR found for low-z SF galaxies applies to high-z galaxies and extend at least 2 orders of magnitude higher in Sigma_FIR. This lends further credence to the claim that the compactness of the IR-emitting region is the controlling parameter in establishing the "[CII] deficit."
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