2006/03/30 by Charles W. Danforth, Charles Danforth, William P. Blair · 1 citation
Chemistry · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Chemistry #Galaxy #Gamma-ray bursts and supernovae #Halo #Interstellar medium #Large Magellanic Cloud #Line (geometry) #Line-of-sight #Physics #Spectral line #Stars #Stellar, planetary, and galactic studies #Superbubble #astro-ph
paper · pdf · doi:10.1086/504706
published as Astrophys.J. 646 (2006) 205-212 · 9 pages in emulateapj style. Accepted to ApJ
arxiv created 2006/03/30 · openalex publication_date 2006/07/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present Far Ultraviolet Spectroscopic Explorer ( FUSE ) observations toward four stars in the Large Magellanic Cloud (LMC) superbubble N70 and compare these spectra to those of four comparison targets located in nearby field and diffuse regions. The N70 sight lines show O VI λ1032 absorption that is consistently stronger than the comparison sight lines by ~60%. We attribute the excess column density ( N = 10 14.03 cm -2 ) to hot gas within N70, potentially the first detection of O VI associated with a superbubble. In a survey of 12 LMC sight lines, Howk and collaborators concluded that there was no correlation between ISM morphology and N . We present a reanalysis of their measurements combined with our own and find a clear difference between the superbubble and field samples. The five superbubbles probed to date with FUSE show a consistently higher mean N than the 12 nonsuperbubble sight lines, although both samples show equivalent scatter from halo variability. Possible ionization mechanisms for N70 are discussed, and we conclude that the observed O VI could be the product of thermal conduction at the interface between the hot, X-ray-emitting gas inside the superbubble and the cooler, photoionized material making up the shell seen prominently in Hα. We calculate the total hydrogen density n H implied by our O VI measurements and find a value consistent with expectations. Finally, we discuss emission-line observations of O VI from N70.