The Extinction Law in High-Redshift Galaxies

We estimate the dust extinction laws in two intermediate-redshift galaxies. The dust in the lens galaxy of LBQS 1009-0252, which has an estimated lens redshift of zl ≃ 0.88, appears to be similar to that of the SMC, with no significant feature at 2175 Å. Only if the lens galaxy is at a redshift of zl ≃ 0.3, which is completely inconsistent with the galaxy colors, luminosity, and location on the fundamental plane, can the data be fitted with a normal Galactic extinction curve. The dust in the zl = 0.68 lens galaxy for B028+357, whose reddened image lies behind a molecular cloud, requires a very flat ultraviolet extinction curve with (formally) RV = 12 ± 2. Both lens systems seem to have unusual extinction curves by Galactic standards.