Using the SWIFT simulation code we study different forms of active galactic nuclei (AGN) feedback in idealized galaxy groups and clusters. We first present a physically motivated model of black hole (BH) spin evolution and a numerical implementation of thermal isotropic feedback (representing the effects of energy-driven winds) and collimated kinetic jets that they launch at different accretion rates. We find that kinetic jet feedback is more efficient at quenching star formation in the brightest cluster galaxies (BCGs) than thermal isotropic feedback, while simultaneously yielding cooler cores in the intracluster medium (ICM). A hybrid model with both types of AGN feedback yields moderate star formation rates, while having the coolest cores. We then consider a simplified implementation of AGN feedback by fixing the feedback efficiencies and the jet direction, finding that the same general conclusions hold. We vary the feedback energetics (the kick velocity and the heating temperature), the fixed efficiencies and the type of energy (kinetic versus thermal) in both the isotropic and the jet case. The isotropic case is largely insensitive to these variations. In particular, we highlight that kinetic isotropic feedback (used e.g. in IllustrisTNG) is similar in its effects to its thermal counterpart (used e.g. in EAGLE). On the other hand, jet feedback must be kinetic in order to be efficient at quenching. We also find that it is much more sensitive to the choice of energy per feedback event (the jet velocity), as well as the efficiency. The former indicates that jet velocities need to be carefully chosen in cosmological simulations, while the latter motivates the use of BH spin evolution models.
The degree of porosity in interstellar dust-grain material is poorly defined, although recent work has suggested that the grains could be highly porous. Aside from influencing the optical properties of the dust, porosity has the potential to affect the chemistry occurring on dust-grain surfaces, via increased surface area, enhanced local binding energies, and the possibility of trapping of molecules within the pores as ice mantles build up on the grains. Through computational kinetics simulations, we investigate how interstellar grain-surface chemistry and ice composition are affected by the p…
Jet feedback from active galactic nuclei (AGN) is one of the most promising mechanisms for suppressing cooling flows in cool-core clusters. However, the composition of AGN jets and bubbles remains uncertain; they could be thermally dominated, or dominated by cosmic-ray proton (CRp), cosmic-ray electron (CRe), or magnetic energy. In this work, we investigate the evolution and feedback effects of CRp and CRe dominated jets by conducting 3D magnetohydrodynamic simulations of AGN jet-inflated bubbles in the intracluster medium using the FLASH code. We present the evolution of their energies, dynam…
Simulating megaparsec-scale jets of radio galaxies: Magneto-hydrodynamics of jets reaching 5 Mpc
Istituto Nazionale di Astrofisica (INAF) – Istituto di Radioastronomia (IRA)（意大利国家天体物理研究所（INAF）- 射电天文研究所（IRA））；Istituto Nazionale di Astrofisica (INAF) - Istituto di Astrofisica e Planetologia Spaziali (IAPS)（意大利国家天体物理研究所（INAF）- 天体物理学与行星科学研究所（IAPS））；Dipartimento di Fisica, Università degli Studi di Torino（都灵大学）；Department of Physics, Indian Institute of Science（印度科学学院物理系 -> 印度科学学院\nen":"Department of Physics, Indian Institute of Science","zh":"印度科学学院"},{）
We present an investigation of the low-frequency radio and ultraviolet properties of a sample of $\simeq$10,500 quasars from the Sloan Digital Sky Survey Data Release 14, observed as part of the first data release of the Low-Frequency-Array Two-metre Sky Survey. The quasars have redshifts $1.5 < z < 3.5$ and luminosities $44.6 < \log(L_{\text{bol}}/\text{erg s}^{-1}) < 47.2$. We employ ultraviolet spectral reconstructions based on an independent component analysis to parametrize the CIV$λ$1549-emission line that is used to infer the strength of accretion disc winds, and the HeII$λ$1640 line, a…
Solving the cooling flow problem with combined jet-wind AGN feedback
Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；University of Chinese Academy of Sciences（中国科学院大学）；Fudan University（复旦大学）；ShanghaiTech University（上海科技大学）；University of Massachusetts（马萨诸塞大学）；Shanghai Jiao Tong University（上海交通大学）；University of Alabama in Huntsville（阿拉巴马大学亨茨维尔分校）
Galactic-scale evolution of classical and complex radio galaxies. Impact of ambient morphology and jet geometry
Istituto Nazionale di Astrofisica (INAF) – Istituto di Radioastronomia (IRA)（意大利国家天体物理研究所（INAF）- 射电天文研究所）；Indian Institute of Astrophysics（印度天体物理研究所）；Núcleo de Astrofísica, Universidade Cidade de São Paulo（圣保罗城市大学天体物理中心）；INAF/Osservatorio Astrofisico di Torino（意大利国家天体物理研究所/都灵天文台）；Department of Physics, University of Bath（巴斯大学物理系）；Department of Physics, University of Pretoria（比勒陀利亚大学物理系）；Centre for Radio Astronomy Techniques and Technologies, Department of Physics and Electronics, Rhodes University（罗德斯大学物理与电子学院射电天文技术与方法中心）；Istituto Nazionale di Astrofisica (INAF) - Istituto di Astrofisica e Planetologia Spaziali (IAPS)（意大利国家天体物理研究所（INAF）- 天体物理学与行星科学研究所）
We examine the physical conditions, environments, and statistical properties of intergalactic Ovi, Ovii and Oviii absorbers in the Simba cosmological hydrodynamic simulation suite. The goal is to understand the nature of these high ionisation absorbers, and test Simba's surprising prediction that $\sim 70\%$ of cosmic baryons at $z=0$ are in the Warm-Hot Intergalactic Medium (WHIM) driven by jet feedback from active galactic nuclei (AGN). By comparing a full-physics Simba run versus one with jets turned off, we find that jet feedback causes widespread heating that impacts the absorption morpho…
The University of Tokyo（东京大学）；Kavli IPMU (WPI), UTIAS（Kavli宇宙起源研究核心理论中心（WPI），UTIAS）；The University of Osaka（大阪大学）；University of Nevada, Las Vegas（内华达大学拉斯维加斯分校）；Nevada Center for Astrophysics（内华达天体物理中心）；Institute for Advanced Study in Physics, Hangzhou（杭州高等研究院）
