Miguel A. de Avillez
Universidade de Évora
(
Título/Title: Testing Current Day Models of the ISM with the Local Bubble
Resumo/Abstract:
|
A
crucial test to present day models of the interstellar medium (ISM) is the
reproduction of the measured amount of the Li-like ions C iv, N v and O vi in
the Local Bubble (LB). Following previous work, we carried out 3D HD and MHD
simulations, with and without heat conduction, of the Local and Loop I
bubbles in a turbulent medium driven by supernovae at the observed Galactic SN
rate. The Local Bubble (LB) is powered by the explosion of massive stars from
the Upper Centaurus Lupus and Lower Centaurus Crux clusters during their passage within the
LB cavity. The ions C iv, N v and O vi , and the distribution of their column density ratios
(N(C iv) /N(O vi) and N(N v) /N(Ovi) )
in the simulations are monitored through lines of sight (with lengths as
large as 150 pc) emanating from the Solar position. We _nd
that these measurements are consistent with the results obtained by the
Copernicus and FUSE satellites, i.e., (i) the Ovi clumpy distribution, (ii) the constancy of the N(O vi) dispersion with distance, (iii)
the N(O vi) being < 8 x 10^12
cm^-2, and (iv) log[N(C iv) /N(O
vi) ] and log[N(N V) /N(O vi) ] being smaller than -1. In
addition, the models show that the presence of heat conduction does not alter
the results because of the dominant rôle of
turbulent mixing in the redistribution of energy inside the bubble. |
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