Zusammenfassung
We explore the abundance, spatial distribution, and physical properties of
the OVI, OVII, and OVIII ions of oxygen in circumgalactic and intergalactic
media (the CGM, IGM, and WHIM). We use the TNG100 and TNG300 large volume
cosmological magneto-hydrodynamical simulations. Modeling the ionization states
of simulated oxygen, we find good agreement with observations of the
low-redshift OVI column density distribution function (CDDF), and present its
evolution for all three ions from z=0 to z=4. Producing mock quasar absorption
line spectral surveys, we show that the IllustrisTNG simulations are fully
consistent with constraints on the OVI content of the CGM from COS-Halos and
other low redshift observations, producing columns as high as observed. We
measure the total amount of mass and average column densities of each ion using
hundreds of thousands of simulated galaxies spanning 10^11 < Mhalo/Msun < 10^15
corresponding to 10^9 < M*/Msun < 10^12 in stellar mass. The stacked radial
profiles of OVI around halos of different masses are computed in 3D number
density as well as 2D projected column, decomposing into the 1-halo and 2-halo
terms, the latter of which begins to dominate for Milky Way mass halos in the
WHIM just beyond the virial radius. Relating halo OVI to properties of the
central galaxy, we find a correlation between the (g-r) color of a galaxy and
the total amount of OVI in its CGM. In comparison to the COS-Halos finding,
this leads to a dichotomy of columns around star-forming versus passive
galaxies at fixed stellar (or halo) mass. We demonstrate that this correlation
is a direct result of blackhole feedback associated with quenching, which also
produces additional trends with other galaxy properties, and represents a
causal consequence of galactic-scale baryonic feedback impacting the physical
state of the circumgalactic medium.
Beschreibung
[1712.00016] The abundance, distribution, and physical nature of highly ionized oxygen OVI, OVII, and OVIII in IllustrisTNG
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