SIMBA: the average properties of the circumgalactic medium of 2 ≤ z ≤ 3 quasars are determined primarily by stellar feedback
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Date
2020-10-05
Journal Title
Journal ISSN
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Publisher
Oxford University Press
Abstract
We use the SIMBA cosmological hydrodynamic simulation suite to explore the impact of feedback on the circumgalactic medium
(CGM) and intergalactic medium (IGM) around 2 ≤ z ≤ 3 quasars. We identify quasars in SIMBA as the most rapidly accreting
black holes, and show that they are well matched in bolometric luminosity and correlation strength to real quasars. We extract
Lyα absorption in spectra passing at different transverse distances (10 kpc b 10 Mpc) around those quasars, and compare
to observations of the mean Lyα absorption profile. The observations are well reproduced, except within 100 kpc from the
foreground quasar, where SIMBA overproduces absorption; this could potentially be mitigated by including ionization from the
quasar itself. By comparing runs with different feedback modules activated, we find that (mechanical) AGN feedback has little
impact on the surrounding CGM even around these most highly luminous black holes, while stellar feedback has a significant
impact. By further investigating thermodynamic and kinematic properties of CGM gas, we find that stellar feedback, and not
AGN feedback, is the primary physical driver in determining the average properties of the CGM around z ∼ 2–3 quasars. We
also compare our results with previous works, and find that SIMBA predicts much more absorption within 100 kpc than the NYX
and ILLUSTRIS simulations, showing that the Lyα absorption profile can be a powerful constraint on simulations. Instruments
such as VLT-MUSE and upcoming surveys (e.g. WEAVE and DESI) promise to further improve such constraints.
Description
Keywords
Numerical – galaxies, Formation – galaxies, Haloes – intergalactic medium – quasars, Absorption lines
Citation
Dave´, R; Sorini, D; Angles-Alc ´ azar, D. 2020.SIMBA: the average properties of the circumgalactic medium of 2 ≤ z ≤ 3 quasars are determined primarily by stellar feedback. Monthly Notices of the Royal Astronomical Society. 499(2):2760-2784