Survey of O vi absorption in the Large Magellanic Cloud

• Published in: Monthly notices of the Royal Astronomical Society 2011-04, Vol.412 (2), p.1105-1122
• Main Authors: Pathak, A., Pradhan, A. C., Sujatha, N. V., Murthy, J.
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; galaxies: individual: Large Magellanic Cloud; galaxies: ISM; ISM: atoms; ISM: structure; ultraviolet: ISM
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2010.17964.x

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 (Hα 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 five superbubbles for the first time and the superbubbles show an excess O vi absorption of about 40 per cent 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.