Abstract
We report a bimodality in the azimuthal angle ($\Phi$) distribution of gas
around galaxies traced by OVI absorption. We present the mean $\Phi$
probability distribution function of 29 HST-imaged OVI absorbing (EW>0.1A) and
24~non-absorbing (EW<0.1A) isolated galaxies (0.08<z<0.67) within 200kpc of
background quasars. We show that EW is anti-correlated with impact parameter
and OVI covering fraction decreases from 80% within 50kpc to 33% at 200kpc. The
presence of OVI absorption is azimuthally dependent and occurs between
$\pm10-20^\circ$ of the galaxy projected major axis and within
$\pm30^\circ$ of the projected minor axis. We find higher EWs along the
projected minor axis with weaker EWs along the project major axis. Highly
inclined galaxies have the lowest covering fractions due to minimized
outflow/inflow cross-section geometry. Absorbing galaxies also have bluer
colors while non-absorbers have redder colors, suggesting that star-formation
is a key driver in the OVI detection rate. OVI surrounding blue galaxies exists
primarily along the projected minor axis with wide opening angles while OVI
surrounding red galaxies exists primarily along the projected major axis with
smaller opening angles, which may explain why absorption around red galaxies is
less frequently detected. Our results are consistent with CGM originating from
major axis-fed inflows/recycled gas and from minor axis-driven outflows.
Non-detected OVI occurs between $\Phi=20-60^\circ$, suggesting that OVI is
not mixed throughout the CGM and remains confined within the outflows and the
disk-plane. We find low OVI covering fractions within $\pm10^\circ$ of the
projected major axis, suggesting that cool dense gas resides in a narrow planer
geometry surrounded by diffuse OVI gas.
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