%0 Generic %1 johnson2015origin %A Johnson, Sean D. %A Chen, Hsiao-Wen %A Mulchaey, John S. %D 2015 %K cool gas quasar %T On the origin of excess cool gas in quasar host halos %U http://arxiv.org/abs/1505.07838 %X Hydrodynamic simulations of galaxies that include stellar feedback are now able to comfortably reproduce observations of the cool halo gas around star-forming galaxies. Without implementing quasar feedback, however, these simulations under-predict the cool gas content of quasar host halos by more than a factor of two. To better understand the source of this tension, we have compiled an exhaustive sample of 195 quasars at z=1 with constraints on chemically enriched, cool gas traced by MgII absorption in background quasar spectra from the Sloan Digital Sky Survey. We find a strong correlation between quasar luminosity and cool gas covering fraction. In particular, low-luminosity quasars exhibit a mean gas covering fraction comparable to inactive galaxies of similar masses, but more luminous quasars exhibit excess cool gas approaching what is reported previously at z=2.2. Moreover, 40% of the MgII absorption occurs at radial velocities of |v|>300 km/s from the quasar systemic redshift, inconsistent with gas gravitationally bound to the quasar host halo. We discuss possible scenarios to explain the large velocity offsets and observed luminosity dependence of the cool gas near quasars including gas arising in: (1) neighboring halos correlated through large-scale structure at Mpc scales, (2) feedback from luminous quasars, and (3) debris from the mergers thought to trigger luminous quasars. The first of these scenarios can be ruled out by the lack of correlation between quasar luminosity and clustering while the latter two each make distinct predictions that can be tested with additional observations.

@misc{johnson2015origin, abstract = {Hydrodynamic simulations of galaxies that include stellar feedback are now able to comfortably reproduce observations of the cool halo gas around star-forming galaxies. Without implementing quasar feedback, however, these simulations under-predict the cool gas content of quasar host halos by more than a factor of two. To better understand the source of this tension, we have compiled an exhaustive sample of 195 quasars at z=1 with constraints on chemically enriched, cool gas traced by MgII absorption in background quasar spectra from the Sloan Digital Sky Survey. We find a strong correlation between quasar luminosity and cool gas covering fraction. In particular, low-luminosity quasars exhibit a mean gas covering fraction comparable to inactive galaxies of similar masses, but more luminous quasars exhibit excess cool gas approaching what is reported previously at z=2.2. Moreover, 40% of the MgII absorption occurs at radial velocities of |v|>300 km/s from the quasar systemic redshift, inconsistent with gas gravitationally bound to the quasar host halo. We discuss possible scenarios to explain the large velocity offsets and observed luminosity dependence of the cool gas near quasars including gas arising in: (1) neighboring halos correlated through large-scale structure at Mpc scales, (2) feedback from luminous quasars, and (3) debris from the mergers thought to trigger luminous quasars. The first of these scenarios can be ruled out by the lack of correlation between quasar luminosity and clustering while the latter two each make distinct predictions that can be tested with additional observations.}, added-at = {2015-06-01T10:23:59.000+0200}, author = {Johnson, Sean D. and Chen, Hsiao-Wen and Mulchaey, John S.}, biburl = {https://www.bibsonomy.org/bibtex/2e66f5bdfb4d7d47daa839a5b2d7d8568/miki}, description = {[1505.07838] On the origin of excess cool gas in quasar host halos}, interhash = {3fc1b76081fc2627389aa8b920daad3c}, intrahash = {e66f5bdfb4d7d47daa839a5b2d7d8568}, keywords = {cool gas quasar}, note = {cite arxiv:1505.07838Comment: 14 pages with 6 figures. Submitted to MNRAS}, timestamp = {2015-06-01T10:23:59.000+0200}, title = {On the origin of excess cool gas in quasar host halos}, url = {http://arxiv.org/abs/1505.07838}, year = 2015 }