%0 Generic %1 lau2017quasars %A Lau, Marie Wingyee %A Prochaska, J. Xavier %A Hennawi, Joseph F. %D 2017 %K absorption kinematics metal quasar %T Quasars Probing Quasars IX. The Kinematics of the Circumgalactic Medium Surrounding z ~ 2 Quasars %U http://arxiv.org/abs/1705.03476 %X We examine the kinematics of the gas in the environments of galaxies hosting quasars at z ~ 2. We employ 112 projected quasar pairs to study the circumgalactic gas of the foreground quasars in absorption. The sample selects foreground quasars with precise redshift measurements, using emission-lines with precision <= 300 km/s and average offsets from the systemic redshift <= |100 km/s|. We stack the background quasar spectra at the foreground quasar's systemic redshift to study the mean absorption in C II, C IV, and Mg II. We find that the mean absorptions exhibit large velocity widths sigma_v > 300 km/s. The observed widths are consistent with gas in gravitational motion and Hubble flow, and galactic-scale outflows are not be required to explain the large widths. Furthermore, we find that the mean absorptions are asymmetric about the systemic redshift. The mean absorption centroids exhibit small redshift relative to the systemic delta v = +200 km/s, with large intrinsic scatter in the centroid velocities of the individual absorption systems. We show that the observed offsets may be produced if (i) the ionizing radiation from the foreground quasars is anisotropic or intermittent; (ii) the gas is not flowing into the galaxy.

@misc{lau2017quasars, abstract = {We examine the kinematics of the gas in the environments of galaxies hosting quasars at z ~ 2. We employ 112 projected quasar pairs to study the circumgalactic gas of the foreground quasars in absorption. The sample selects foreground quasars with precise redshift measurements, using emission-lines with precision <= 300 km/s and average offsets from the systemic redshift <= |100 km/s|. We stack the background quasar spectra at the foreground quasar's systemic redshift to study the mean absorption in C II, C IV, and Mg II. We find that the mean absorptions exhibit large velocity widths sigma_v > 300 km/s. The observed widths are consistent with gas in gravitational motion and Hubble flow, and galactic-scale outflows are not be required to explain the large widths. Furthermore, we find that the mean absorptions are asymmetric about the systemic redshift. The mean absorption centroids exhibit small redshift relative to the systemic delta v = +200 km/s, with large intrinsic scatter in the centroid velocities of the individual absorption systems. We show that the observed offsets may be produced if (i) the ionizing radiation from the foreground quasars is anisotropic or intermittent; (ii) the gas is not flowing into the galaxy.}, added-at = {2017-05-11T10:14:43.000+0200}, author = {Lau, Marie Wingyee and Prochaska, J. Xavier and Hennawi, Joseph F.}, biburl = {https://www.bibsonomy.org/bibtex/25db93da20118b5e58a3c4dc4dc2959e0/miki}, description = {[1705.03476] Quasars Probing Quasars IX. The Kinematics of the Circumgalactic Medium Surrounding z ~ 2 Quasars}, interhash = {47f928a8944a0856ecc8d233936120ea}, intrahash = {5db93da20118b5e58a3c4dc4dc2959e0}, keywords = {absorption kinematics metal quasar}, note = {cite arxiv:1705.03476}, timestamp = {2017-05-11T10:14:43.000+0200}, title = {Quasars Probing Quasars IX. The Kinematics of the Circumgalactic Medium Surrounding z ~ 2 Quasars}, url = {http://arxiv.org/abs/1705.03476}, year = 2017 }