Open AccessHST /STIS observations of the high‐velocity interstellar cloud HVC 291.2−41.2+80: a warm, mainly ionized high‐velocity cloud
Author(s) -
Lehner N.,
Keenan F. P.,
Sembach K. R.
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04276.x
Subject(s) - physics , astrophysics , spectral line , ionization , interstellar cloud , absorption (acoustics) , absorption spectroscopy , interstellar medium , spectral resolution , astronomy , galaxy , optics , ion , quantum mechanics
We present intermediate‐resolution HST /STIS spectra of a high‐velocity interstellar cloud (v LSR =+80 km s −1 ) towards DI 1388, a young star in the Magellanic Bridge located between the Small and Large Magellanic Clouds. The STIS data have a signal‐to‐noise ratio (S/N) of 20–45 and a spectral resolution of about 6.5 km s −1 (FWHM). The high‐velocity cloud absorption is observed in the lines of C ii , O i , Si ii , Si iii , Si iv and S iii . Limits can be placed on the amount of S ii and Fe ii absorption that is present. An analysis of the relative abundances derived from the observed species, particularly C ii and O i , suggests that this high‐velocity gas is warm (T k ∼10 3 –10 4 K) and predominantly ionized. This hypothesis is supported by the presence of absorption produced by highly ionized species, such as Si iv . This sightline also intercepts two other high‐velocity clouds that produce weak absorption features at v LSR =+113 and +130 km s −1 in the STIS spectra.