%0 Generic %1 armillotta2016survival %A Armillotta, L. %A Werk, J. K. %A Prochaska, J. X. %A Fraternali, F. %A Marinacci, F. %D 2016 %K cgm clouds high-resolution simulations %T The survival of gas clouds in the Circumgalactic Medium of Milky-Way-like galaxies %U http://arxiv.org/abs/1608.05416 %X Observational evidence shows that low-redshift galaxies are surrounded by extended haloes of multiphase gas, the so-called 'circumgalactic medium' (CGM). To study the survival of relatively cool gas (T < 10^5 K) in the CGM, we performed a set of hydrodynamical simulations of cool (T = 10^4 K) neutral gas clouds travelling through a hot (T = 2x10^6 K) and low-density (n = 10^-4 cm^-3) coronal medium, typical of Milky Way-like galaxies at large galactocentric distances (~ 50-150 kpc). We explored the effects of different values of relative velocity and radius of the clouds. Our simulations include radiative cooling, photoionization heating and thermal conduction. The main result is that large clouds (radii larger than 250 pc) may survive for very long time (at least 250 Myr): their mass decreases during their trajectory but at very low rates. We found that thermal conduction plays a significant role: its effect is to prevent formation of Kelvin-Helmholtz instabilities at the cloud-corona interface, keeping the cloud compact and therefore more difficult to destroy. The distribution of column densities in our simulations are compatible with those observed for low-temperature ions (e.g. SiII and SiIII) and for high-ions (OVI) once we take into account that OVI covers much more extended regions than the cool gas and, therefore, it is more likely to be detected along a generic line of sight.

@misc{armillotta2016survival, abstract = {Observational evidence shows that low-redshift galaxies are surrounded by extended haloes of multiphase gas, the so-called 'circumgalactic medium' (CGM). To study the survival of relatively cool gas (T < 10^5 K) in the CGM, we performed a set of hydrodynamical simulations of cool (T = 10^4 K) neutral gas clouds travelling through a hot (T = 2x10^6 K) and low-density (n = 10^-4 cm^-3) coronal medium, typical of Milky Way-like galaxies at large galactocentric distances (~ 50-150 kpc). We explored the effects of different values of relative velocity and radius of the clouds. Our simulations include radiative cooling, photoionization heating and thermal conduction. The main result is that large clouds (radii larger than 250 pc) may survive for very long time (at least 250 Myr): their mass decreases during their trajectory but at very low rates. We found that thermal conduction plays a significant role: its effect is to prevent formation of Kelvin-Helmholtz instabilities at the cloud-corona interface, keeping the cloud compact and therefore more difficult to destroy. The distribution of column densities in our simulations are compatible with those observed for low-temperature ions (e.g. SiII and SiIII) and for high-ions (OVI) once we take into account that OVI covers much more extended regions than the cool gas and, therefore, it is more likely to be detected along a generic line of sight.}, added-at = {2016-08-22T10:48:44.000+0200}, author = {Armillotta, L. and Werk, J. K. and Prochaska, J. X. and Fraternali, F. and Marinacci, F.}, biburl = {https://www.bibsonomy.org/bibtex/230bed365a792898e80166f2403b72b19/miki}, description = {[1608.05416] The survival of gas clouds in the Circumgalactic Medium of Milky-Way-like galaxies}, interhash = {6ccb06ca1dfbc10ffa68c1348c6b3731}, intrahash = {30bed365a792898e80166f2403b72b19}, keywords = {cgm clouds high-resolution simulations}, note = {cite arxiv:1608.05416Comment: 10 pages, 6 figures. Submitted to MNRAS. Comments welcome}, timestamp = {2016-08-22T10:48:44.000+0200}, title = {The survival of gas clouds in the Circumgalactic Medium of Milky-Way-like galaxies}, url = {http://arxiv.org/abs/1608.05416}, year = 2016 }