New quasars Ca II absorbers with SDSS spectra

Our CA II rest-frame equivalent width distribution supports the weak and strong subpopulations, split at W_0_^{lambda}3934^ = 0.7{AA}. Comparison of both populations' dust depletion shows clear consistency for weak absorber association with halo-type gas in the Milky Way (MW), while strong absorbers have environments consistent with halo and disc- type gas.

We probed our high-redshift Ca II absorbers for 2175{AA} dust bumps, discovering 122175 {AA} dust absorbers (2DAs). This clearly shows that some Ca II absorbers follow the Large Magellanic Cloud (LMC) extinction law rather than the Small Magellanic Cloud extinction law. About 33 per cent of our strong Ca II absorbers exhibit the 2175 {AA} dust bump, while only 6 per cent of weak Ca II absorbers show this bump. 2DA detection further supports the theory that strong Ca II absorbers are associated with disc components and are dustier than the weak population.