| |< | | < | | ^ | | > | | >| |
Q 0454-220
V = 15.5; z = 0.534; exp = 5400 s; coverage = 3765.8-6198.9 A
Spectra of this QSO were previously studied by Tytler et al. (1987) and by Robertson et al.(1988), and references to the Mg II system discoveries are given in those works.
z=0.474410 |DATA & VOIGT PROFILES| |EWs & AOD COLUMNS| |VP PARAMETERS|
Tytler et al. (1987) studied this system in some detail. A detection of Ca II has been reported by Robertson et al. (1988), and is confirmed with this work. Their tentative report of Mn II 2584 absorption is not confirmed, however, a small apparent feature is present at about v = 10 km/s. This not taken to be a positive detection of the Mn II transition since the detection threshold of the other Mn II transitions are roughly the same and these transitions show no absorption to the limits given in Table 3.20. A total of 16 VP components were fit to this broad saturated profile. It is most interesting to note the relatively narrow and highly structured Mg I profile and the fact that it is roughly centered on the Mg II profile. The observed Ca II profile is clearly aligned in velocity with the Mg I profile and likely arises in the same spatial region of the absorbing gas. The VP decomposition of this system suffered from a singular curvature matrix during the computation of the uncertainties. Thus, inferences regarding this system based upon the VP parameters should be viewed with suspicion. In fact, this system has been omitted from the statistical studies of VP parameters. The Fe II 2344, 2374, and 2383 transitions were not covered by the HIRES format and the Ca II 3934 transition was only partially observed.
z=0.483340 |DATA & VOIGT PROFILES| |EWs & AOD COLUMNS| |VP PARAMETERS|Tytler et al.(1987) also studied this system in some detail. A null detection of Ca II has been reported by Robertson et al. (1988). However, Ca II absorption is detected in the HIRES spectrum, albeit below the detection threshold of the Robertson et al. spectrum. The profile was fit with a total of seven VP components, which were all well constrained in that they have small fractional errors. The Fe II is aligned in velocity with the maximum Mg II absorption, as is the Ca II absorption. However, the Mg I shows a hint of structure that may span the full velocity spread seen in the Mg II profiles. The Mn II triplet showed no absorption to the EW(rest) limits given in Table 3.21.
Post Thesis WorkFOS/HST data have been investigated.
See Churchill et al. (2000a)
See Churchill et al. (2000b)
|PREVIOUS QSO| |NEXT QSO| | QSO LISTING | |TABLE OF CONTENTS| |CWC HOME|