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The strongest spectroscopic dust extinction feature in the Milky Way, thebroad absorption bump at 2175 \AA, is generally believed to be caused byaromatic carbonaceous materials -- very likely a mixture of Polycyclic AromaticHydrocarbon (PAH) molecules, the most abundant and widespread organic moleculesin the Milky Way galaxy. In this paper we report identifications of thisabsorption feature in three galaxies at $1.4 \lesssim z \lesssim 1.5$ whichproduce intervening MgII absorption toward quasars discovered by the SloanDigital Sky Survey (SDSS). The observed spectra can be fit using Galactic-typeextinction laws, characterized by parameters [R_V, E(B-V)] ~ [0.7, 0.14], [1.9,0.13], and [5.5, 0.23], respectively, where R_V=A_V/E(B-V) is thetotal-to-selective extinction ratio, E(B-V) = A_B-A_V is the color-excess.These discoveries imply that the dust in these distant quasar absorptionsystems is similar in composition to that of Milky Way, but with a range ofdifferent grain size distributions. The presence of complex aromatichydrocarbon molecules in such distant galaxies is important for bothastrophysical and astrobiological investigations.Comment: 20 pages, 4 figures, accepted for publication in ApJ July 10 issu

Detections of the 2175 A Dust Feature at 1.4 ≲ z ≲ 1.5 from the Sloan Digital Sky Survey