Redshift evolution of galaxy group X-ray properties in the SIMBA simulations
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Date
2023
Authors
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Journal ISSN
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Publisher
Oxford University Press
Abstract
We examine the evolution of intragroup gas rest-frame X-ray scaling relations for group-sized haloes (M500 = 1012.3–1015 M)
in the SIMBA galaxy formation simulation. X-ray luminosity LX versus M500 shows increasing deviation from self-similarity from
z = 3 → 0, with M500 < 1013.5 M haloes exhibiting a large reduction in LX and slight increase in X-ray luminosity-weighted
temperature TX. These shifts are driven by a strong drop in fgas with time for these haloes, and coincides with the onset of
SIMBA’s black hole (BH) jet feedback, occurring when MBH > 107.5 M and Eddington ratio <0.2, in group haloes at z ∼ 1.5.
The connection with BH feedback is corroborated by fBH ≡ MBH/M500 in M500 < 1013.5 M haloes being strongly anticorrelated
with LX and fgas at z 1.5. This is further reflected in the scatter of LX − TX: haloes with small fBH lie near self-similarity, while
those with the highest fBH lie furthest below. Turning off jet feedback results in mostly self-similar behaviour down to z = 0.
For the X-ray weighted metallicity ZX, stellar feedback impacts the enrichment of halo gas. Finally, halo profiles show that jet
feedback flattens the electron density and entropy profiles, and introduces a core in X-ray surface brightness, particularly at M500
< 1013.5 M. This argues that in SIMBA, intragroup X-ray evolution is largely driven by jet feedback removing hot gas from the
cores of massive groups, and expelling gas altogether in less massive groups.
Description
Keywords
Astronomy, Physics, Galaxies formation, Galaxy evolution
Citation
Robson, D., & Dave, R. (2023). Redshift evolution of galaxy group X-ray properties in the SIMBA simulations. Monthly Notices of the Royal Astronomical Society, 518(4), 5826–5842. https://doi.org/10.1093/mnras/stac2982