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P. Ghavamian, R. Sankrit, W. P. Blair ()
We present the first ultraviolet spectra of the four known Balmer-dominated supernova remnants (SNRs) in the LMC. The remnants 0505-67.9 (DEM L 71), 0509-67.5, 0519-69.9 and 0548-70.4 are all in the adiabatic stages of evolution and exhibit expansion speeds ranging from 500 km/s to > 3000 km/s. Chandra observations have shown that the X-ray emission from these SNRs is dominated by reverse-shocked ejecta and that they were produced by Type Ia explosions. The blast waves of these remnants are currently encountering partially neutral gas, giving rise to Balmer-dominated emission in the optical and Lyman lines in the far ultraviolet.
Each target was observed for a total of 30 ks through the low resolution (30'' square) aperture of FUSE, with 10 ks of the data acquired during orbital night. The aperture was aimed at the center of each SNR, and in the cases of 0509-67.5 and 0519-69.9 was large enough to encompass the entire blast wave shell. We have detected strong, broad emission lines of Ly beta, Ly gamma and O VI in 0505-67.9 (velocity widths ~ 1000 km/s) and 0519-69.9 (velocity widths ~ 3000 km/s). In the remaining SNRs we can only place an upper limit on the detection of emission lines. In the case of 0505-67.9 we may have detected Fe XVIII 974 emission from the shocked iron-rich ejecta synthesized during the supernova explosion. Recent Chandra observations of this remnant have revealed the presence of 0.8 solar masses or more of iron, so if a detailed analysis confirms a detection of Fe XVIII it would provide valuable information on the ionization state and velocity on the ejecta.
This work is based on data obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated by the Johns Hopkins University. Financial support to U.S. participants has been provided by NASA contract NAS5-32985.
The author(s) of this abstract have provided an email address for comments about the abstract: parviz@pha.jhu.edu
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.