2005) have also helped to identify AGN analogues of low/hard state sources, in which the radiative efﬁciency of the accretion ﬂow is low (Pellegrini 2005a; Chiaberge, Capetti & Macchetto 2005; Hardcastle, Evans & Croston 2007) and the radio emitting jet carries a substantial fraction of the overall power in kinetic form (K¨ording, Fender & Migliari 2006). Nonetheless, despite such a widespread consensus on the importance of kinetic energy feedback from AGN for galaxy formation, the kinetic luminosity of an AGN remains very difﬁcult to estimate reliably. Recent incarnations of structure formation models (either numerical or semi-analytic) hinge on the unknown efﬁciency with which growing black holes convert accreted rest mass into jet power. Constraints on this quantity, such as those recently presented in Heinz, Merloni & Schwab (2007) are clearly vital for the robustness of the models. Observationally, progress has been possible recently, thanks to deep X-ray exposures of nearby elliptical galaxies and clusters which have allowed the ﬁrst direct estimates of Lkin by studying the cavities, bubbles and weak shocks generated by the radio emitting jets in the intra-cluster medium (ICM) (Bˆırzan et al.
Studies conducted in 2005 have contributed to identifying AGN analogs of low/hard state sources, where the radiative efficiency of the accretion flow is low (Pellegrini 2005a; Chiaberge, Capetti & Macchetto 2005; Hardcastle, Evans & Croston 2007) and a significant portion of the total power is carried by the radio-emitting jet in the form of kinetic energy (Körding, Fender & Migliari 2006). However, despite broad agreement on the role of AGN kinetic energy feedback in galaxy formation, accurately estimating the kinetic luminosity of an AGN remains challenging. Current structure formation models, whether numerical or semi-analytic, rely on the uncertain efficiency with which growing black holes convert accreted mass into jet power. Constraints on this efficiency, such as those provided by Heinz, Merloni & Schwab (2007), are crucial for the reliability of these models. Recent observational advancements, enabled by deep X-ray observations of nearby elliptical galaxies and clusters, have allowed for the first direct estimates of kinetic luminosity by analyzing cavities, bubbles, and weak shocks produced by radio jets in the intra-cluster medium (ICM) (Bîrzan et al.).
Research has contributed to identifying active galactic nuclei (AGN) analogues of low/hard state sources, where the accretion flow exhibits low radiative efficiency and the radio jets carry a significant portion of overall kinetic power. While there is broad agreement on the role of kinetic energy feedback from AGN in galaxy formation, estimating the kinetic luminosity of an AGN remains challenging. Current structure formation models, both numerical and semi-analytical, depend on the uncertain efficiency of how growing black holes convert accreted mass into jet power. Understanding this efficiency is essential for the validity of these models. Recent observational advancements, particularly from deep X-ray studies of nearby elliptical galaxies and clusters, have facilitated initial estimates of kinetic luminosity by analyzing the cavities, bubbles, and weak shocks produced by radio jets in the intra-cluster medium.
Studies have helped to find AGN analogues of low/hard state sources, in which the accretion flow is low in radiative efficiency and the radio jets carry a large fraction of the total kinetic power. Although the contribution of AGN kinetic energy feedback to galaxy formation is generally accepted, the kinetic luminosity of an AGN is still difficult to estimate. Numerical and semi-analytical structure formation models rely on the ambiguous efficiency of the conversion of accreted mass into jet power by growing black holes. This efficiency is crucial for the reliability of these models. Recent observational developments, especially deep X-ray observations of nearby elliptical galaxies and clusters, have allowed for preliminary determinations of kinetic luminosity by studying the cavities, bubbles and weak shocks generated by radio jets in the intra-cluster medium.
Studies have helped to pinpoint AGN analogues of low/hard state sources, where the accretion flow is characterized by low radiative efficiency and the radio jets are responsible for a large fraction of the total kinetic power. Although there is general consensus on the importance of kinetic energy feedback from AGN in galaxy formation, the kinetic luminosity of an AGN is difficult to measure. The present numerical and semi-analytical structure formation models are based on the unresolved efficiency of the conversion of accreted mass into jet power by growing black holes. This efficiency is important for the validity of these models. Recent progress in observations, especially from deep X-ray observations of nearby elliptical galaxies and clusters, has enabled first estimates of kinetic luminosity by studying the cavities, bubbles and weak shocks formed by radio jets in the intra-cluster medium.