Survey of O VI absorption in the Large Magellanic Cloud

TL;DR

This survey analyzes interstellar O VI absorption in the Large Magellanic Cloud using FUSE data, revealing its patchy distribution, lack of correlation with some emissions, and differences compared to the Milky Way and SMC.

Contribution

It provides the first detection of O VI absorption in five LMC superbubbles and compares O VI properties across different regions and environments within the LMC.

Findings

O VI is abundant in both active and inactive regions of the LMC.

O VI absorption is patchy and similar to that in the Milky Way.

O VI abundance is lower in the SMC despite its lower metallicity.

Abstract

We present a survey of interstellar O VI absorption in the Large Magellanic Cloud (LMC) towards 70 lines of sight based on Far Ultraviolet Spectroscopic Explorer (FUSE) observations. The survey covers O VI absorption in a large number of objects in different environmental conditions of the LMC. Overall, a high abundance of O VI is present in active and inactive regions of the LMC with mean log[N(O VI)] = 14.23 atoms cm$^{-2}$. There is no correlation observed between O VI absorption and emissions from the hot gas (X-ray surface brightness) or the warm gas (H$_{\alpha}$ surface brightness). O VI absorption in the LMC is patchy and the properties are similar to that of the Milky Way (MW). In comparison to the Small Magellanic Cloud (SMC), O VI is lower in abundance even though SMC has a lower metallicity compared to the LMC and the MW. We present observations in 10 superbubbles of the LMC of which we detect O VI absorption in 5 superbubbles for the first time and the superbubbles show an excess O VI absorption of about 40% compared to non-superbubble lines of sight. We have also studied the properties of O VI absorption in the 30 Doradus region. Even though O VI does not show any correlation with X-ray emission for the LMC, a good correlation between log[N(O VI)] and X-ray surface brightness for 30 Doradus region is present. We also find that O VI abundance decreases with increasing distance from the star cluster R136.