%0 Generic %1 chisholm2017feeding %A Chisholm, J. %A Bordoloi, R. %A Rigby, J. R. %A Bayliss, M. %D 2017 %K OVI galactic outflow %T Feeding the fire: Tracing the mass-loading of 10^7 K galactic outflows with O VI absorption %U http://arxiv.org/abs/1710.06857 %X Galactic outflows regulate the amount of gas galaxies convert into stars. However, it is difficult to measure the mass outflows remove because they span a large range of temperatures and phases. Here, we study the rest-frame ultraviolet spectrum of a lensed galaxy at z~2.9 with prominent interstellar absorption lines from O I, tracing neutral gas, up to O VI, tracing transitional phase gas. The O VI profile mimics weak low-ionization profiles at low velocities, and strong saturated profiles at high velocities. These trends indicate that O VI gas is co-spatial with the low-ionization gas. Further, at velocities blueward of -200 km/s the column density of the low-ionization outflow rapidly drops while the O VI column density rises, suggesting that O VI is created as the low-ionization gas is destroyed. Photoionization models do not reproduce the observed O VI, but adequately match the low-ionization gas, indicating that the phases have different formation mechanisms. Photoionized outflows are more massive than O VI outflows for most of the observed velocities, although the O VI mass outflow rate exceeds the photoionized outflow at velocities above the galaxy's escape velocity. Therefore, most gas capable of escaping the galaxy is in a hot outflow phase. We suggest that the O VI absorption is a temporary by-product of conduction transferring mass from the photoionized phase to an unobserved hot wind, and discuss how this mass-loading impacts the observed circum-galactic medium.

@misc{chisholm2017feeding, abstract = {Galactic outflows regulate the amount of gas galaxies convert into stars. However, it is difficult to measure the mass outflows remove because they span a large range of temperatures and phases. Here, we study the rest-frame ultraviolet spectrum of a lensed galaxy at z~2.9 with prominent interstellar absorption lines from O I, tracing neutral gas, up to O VI, tracing transitional phase gas. The O VI profile mimics weak low-ionization profiles at low velocities, and strong saturated profiles at high velocities. These trends indicate that O VI gas is co-spatial with the low-ionization gas. Further, at velocities blueward of -200 km/s the column density of the low-ionization outflow rapidly drops while the O VI column density rises, suggesting that O VI is created as the low-ionization gas is destroyed. Photoionization models do not reproduce the observed O VI, but adequately match the low-ionization gas, indicating that the phases have different formation mechanisms. Photoionized outflows are more massive than O VI outflows for most of the observed velocities, although the O VI mass outflow rate exceeds the photoionized outflow at velocities above the galaxy's escape velocity. Therefore, most gas capable of escaping the galaxy is in a hot outflow phase. We suggest that the O VI absorption is a temporary by-product of conduction transferring mass from the photoionized phase to an unobserved hot wind, and discuss how this mass-loading impacts the observed circum-galactic medium.}, added-at = {2017-10-20T10:18:15.000+0200}, author = {Chisholm, J. and Bordoloi, R. and Rigby, J. R. and Bayliss, M.}, biburl = {https://www.bibsonomy.org/bibtex/2a8235a897da2d64ceda8934a687de318/miki}, description = {[1710.06857] Feeding the fire: Tracing the mass-loading of 10^7 K galactic outflows with O VI absorption}, interhash = {c172795177fa30d38cb5e6f413749349}, intrahash = {a8235a897da2d64ceda8934a687de318}, keywords = {OVI galactic outflow}, note = {cite arxiv:1710.06857Comment: 17 pages, 12 figures, resubmitted to MNRAS after initial referee comments}, timestamp = {2017-10-20T10:18:15.000+0200}, title = {Feeding the fire: Tracing the mass-loading of 10^7 K galactic outflows with O VI absorption}, url = {http://arxiv.org/abs/1710.06857}, year = 2017 }