Redshift Evolution of Galaxy Group X-ray Properties in Simba

Abstract

We examine the evolution of intragroup gas X-ray scaling relations for group-sized halos (M 500 = 10 12.3−15 M ) in the Simba galaxy formation simulation. X-ray luminosity L X vs M 500 shows increasing deviation from self-similarity from z = 3 → 0, with M 500 < 10 13.5 M halos exhibiting a large reduction in L X and slight increase in X-ray luminosityweighted temperature T X . These shifts are driven by a strong drop in f gas with time for these halos, and coincides with the onset of black hole jet feedback in these systems at z ∼ 1.5 in Simba. The connection with black hole feedback is corroborated by f BH ≡ M BH /M 500 in M 500 < 10 13.5 M halos being strongly anti-correlated with L X and f gas at z < ∼ 1.5. This is further reflected in the scatter of L X − T X : halos 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 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.

Cosmological Simulation of Galaxy Groups and Clusters. II. Studying Different Modes of Feedback through X-Ray Observations

“…However, it is higher in the radiative mode, and as reported by Davé et al (2019), it seems to be more prominent in lower-mass halos. Similar results have been reported by Robson & Davé (2021), where they have looked at the redshift evolution of the profiles in different halo mass bins using SIMBA data. This result is in agreement with Kar Chowdhury et al (2020), who use the D08 simulation; the model for AGN feedback in D08 is equivalent to that of the "radiative wind" mode.…”

Galaxy mergers can initiate quenching by unlocking an AGN-driven transformation of the baryon cycle

“…In these simulations, correlations exist (at fixed halo mass) between the central BH mass, halo gas content and galaxy star formation rate (Davies et al 2019(Davies et al , 2020Davé et al 2019;Terrazas et al 2020;Appleby et al 2021;Cui et al 2021;Robson & Davé 2021), and the cooling time of the CGM (Davies et al 2020;Zinger et al 2020), such that quenched galaxies typically host overmassive BHs and have gaspoor and inefficiently-cooling circumgalactic reservoirs. Together, these correlations suggest that for quiescence to be achieved and maintained in Milky Way-like galaxies, AGN feedback must eject a large fraction of the CGM over the galaxy's lifetime, preventing the CGM from efficiently cooling and replenishing the galaxy's gas supply for star formation.…”

\textsc{The Three Hundred} project: The \textsc{Gizmo-Simba} run

“…The differences in the gas fractions (and associated slight differences in the stellar fractions) emerging at 𝑧 ∼ 2−3 can be understood from an interplay between halo growth and star formation quenching. As shown in ; Robson & Davé (2021), it is at this redshift when G -S 's jet mode AGN feedback turns on in these massive halos, which is what drives galaxy quenching (Davé et al 2019). With star formation curtailed and the halo having a stable virial shock (Kereš et al 2005;Dekel & Birnboim 2006), accreted gas can be held up and accumulated in the halo, causing the gas fractions to increase and the stellar fractions to drop.…”

“…which is when Simba's jet mode AGN feedback which becomes important prominent in this mass range (Robson & Davé 2021). The gas fraction continues to drop more rapidly in G -S that in G -X down to 𝑧 = 0 in 𝑀 500 < ∼ 10 14.5 𝑀 halos.…”