Zusammenfassung
We explore the multiphase structure of the circumgalactic medium (CGM) probed
by synthetic spectra through a cosmological zoom-in galaxy formation
simulation. We employ a Bayesian method for modeling a combination of
absorption lines to derive physical properties of absorbers regardless of the
signal-to-noise or whether a particular line is actually detected. This allows
us to treat detections (including saturated systems) and non-detections in a
uniform manner. We find that in the lines of sight passing through localized
density structures, absorption lines of low, intermediate and high ions are
present in the spectrum and overlap in velocity space. To our surprise, all of
the ions can be combined to derive the line of sight (LOS) mass-weighted
properties, although the ions are not co-spatial. In lines of sight that go
through the hot halo, only HI and high ions are present. In such lines of
sight, the absorption lines are typically broad due to the complex velocity
fields across the entire halo. We show that the derived gas density,
temperature, and metallicity match closely the corresponding HI mass-weighted
averages along the LOS. We also show that constraints on HI and OVI together
with upper limits on NV and/or NeVIII, can in principle provide constraints on
the properties of the hot halo itself.
Nutzer