We propose to use Gemini/GMOS-N in queue mode to spectroscopically observe 10 projected quasar pairs at 0.3<z<2.5 with separations < 3′ ′ selected from literature and our previous surveys. In such systems, the absorbers of the foreground quasars will project absorption lines onto the background quasars’ spectra. This technique has been proven to be very powerful and unique in studying the column density, temperature, and metallicity of quasar environments, which are important parameters to quantify the growth of SMBHs and their feedback to their host galaxies. We will focus on the Mg II λλ 2796, 2803 doublet since it is the strongest absorption line observable in optical wavebands at 0.3<z<2.5. All of our candidates already have redshift measurements based on previous observations, thus are at least secure as projected quasar pairs, the proposed observation will significantly improve the S/N and resolution for Mg II detection. In this proposal, we constrained to the closest separation below 3′ ′, which corresponds to 20 kpc. This will first make it possible to study the AGN feedback at the very vicinity region of a statistical set of bright type-1 quasars.
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