Environments of luminous low-frequency radio galaxies since cosmic noon: jet-mode feedback dominates in groups

TL;DR

This study shows that luminous low-frequency radio galaxies mainly reside in galaxy groups and that their jet-mode feedback significantly influences the thermal state of group and cluster gas over cosmic time.

Contribution

It provides new observational constraints on the environments of radio galaxies since cosmic noon and demonstrates jet-mode feedback's dominance in group-scale halos.

Findings

Radio galaxies occupy halos of 10^{13}-10^{14} M_sun

Jet feedback dominates over quasar winds in massive halos

Duty cycle of radio galaxies has increased since z~2

Abstract

Coupling between relativistic jets launched by accreting supermassive black holes and the surrounding gaseous media is a vital ingredient in galaxy evolution models. To constrain the environments in which this feedback takes place over cosmic time, we study the host halo properties of luminous low-frequency radio galaxies ($L_{150 \ \mathrm{MHz}} \gtrsim$ 25.25 W/Hz) selected with the International LOFAR Telescope out to $z \sim 2$ through tomographic clustering and cosmic microwave background lensing measurements. We find that these systems occupy halos characteristic of galaxy groups ($M_h = 10^{13} - 10^{14} h^{-1} M_{\odot}$), evolving at a rate consistent with the mean growth rate of halos over the past $\sim$10 Gyr. The coevolution of the clustering and the luminosity function reveals that the duty cycle of these systems is of order $\sim 10\%$ but has been mildly increasing since $z\sim 2$, while the duty cycle of quasars has been declining. We estimate the characteristic kinetic heating power injected by powerful jets per halo as a function of mass, and compare to the same quantity injected by quasar winds. We find that powerful jet heating dominates over quasar winds in halos $M_h \gtrsim 10^{13} h^{-1} M_{\odot}$ at $z < 2$. These results conform to the paradigm of galaxy evolution in which mechanical jet power feedback is the dominant heating mechanism of the gas content of groups and clusters.