Far-Ultraviolet Absorption Lines in the Remnant of SN 1006

摘要

We have obtained a far-ultraviolet spectrum (1150～1600 A) of a hot subdwarf star behind the remnant of supernova 1006 with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope. The high-quality spectrum is used to test previous identifications of the strong absorption features discovered with the International Ultraviolet Explorer. These features have FWHM = 4000 (±300) km s~-1 and are not at the rest wavelengths of known interstellar lines, as opposed to the broader (～8000 km s~-1 FWHM) Fe II lines from the remnant centered at 0 km s~-1 in near-UV FOS spectra. We confirm that the broad absorption features are principally due to redshifted Si II, Si III, and Si IV lines, which are centered at a radial velocity of 5100 (±200) km s~-1.