Redshift evolution of galaxy group X-ray properties in the Simba simulations

We examine the evolution of intragroup gas rest-frame X-ray scaling relations for group-sized haloes (M-500 = 10(12.3)-10(15) M-?) in the Simba galaxy formation simulation. X-ray luminosity L-X versus M-500 shows increasing deviation from self-similarity from z = 3 -> 0, with M-500 < 10(13.5) M-? haloes exhibiting a large reduction in L-X and slight increase in X-ray luminosity-weighted temperature T-X. These shifts are driven by a strong drop in f(gas) with time for these haloes, and coincides with the onset of Simba's black hole (BH) jet feedback, occurring when M-BH > 10(7.5) M-? and Eddington ratio < 0.2, in group haloes at z similar to 1.5. The connection with BH feedback is corroborated by f(BH) equivalent to M-BH/M-500 in M-500 < 10(13.5) M-? haloes being strongly anticorrelated with L-X and f(gas) at z ? 1.5. This is further reflected in the scatter of L-X - T-X: haloes with small f(BH) lie near self-similarity, while those with the highest f(BH) lie furthest below. Turning off jet feedback results in mostly self-similar behaviour down to z = 0. For the X-ray weighted metallicity Z(X), 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 M-500 < 10(13.5) 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.