  Known as the "Missing Baryon Problem", about one-third of baryons in the
local universe remain unaccounted for. The missing baryons are thought to
reside in the warm-hot intergalactic medium (WHIM) of the cosmic web filaments,
which are challenging to detect. Recent Chandra X-ray observations used a novel
stacking analysis and detected an OVII absorption line toward the sightline of
a luminous quasar, hinting that the missing baryons may reside in the WHIM. To
explore how the properties of the OVII absorption line depend on feedback
physics, we compare the observational results with predictions obtained from
the Cosmology and Astrophysics with MachinE Learning (CAMEL) Simulation suite.
CAMELS consists of cosmological simulations with state-of-the-art supernova
(SN) and active galactic nuclei (AGN) feedback models from the IllustrisTNG and
SIMBA simulations, with varying strengths. We find that the simulated OVII
column densities are higher in the outskirts of galaxies than in the
large-scale WHIM, but they are consistently lower than those obtained in the
Chandra observations, for all feedback runs. We establish that the OVII
distribution is primarily sensitive to changes in the SN feedback prescription,
whereas changes in the AGN feedback prescription have minimal impact. We also
find significant differences in the OVII column densities between the
IllustrisTNG and SIMBA runs. We conclude that the tension between the observed
and simulated OVII column densities cannot be explained by the wide range of
feedback models implemented in CAMELS.
