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Main Authors: Ye, Xu-Hong, Baldi, Ranieri D., Chen, Yong-Yun, Bastieri, Denis, Fan, Jun-Hui
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2503.23607
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author Ye, Xu-Hong
Baldi, Ranieri D.
Chen, Yong-Yun
Bastieri, Denis
Fan, Jun-Hui
author_facet Ye, Xu-Hong
Baldi, Ranieri D.
Chen, Yong-Yun
Bastieri, Denis
Fan, Jun-Hui
contents Radio galaxies (RGs) are a subclass of active galactic nuclei, which are suggested to be the parent populations of blazars. According to the accretion-ejection paragram, RGs can be classified into low-excitation or high-excitation radio galaxies (LERGs or HERGs). In this paper, we compiled a distance-limited ($z<0.15$) sample of 431 LERGs (Fanaroff-Riley, or FR, type 0, I, and II RGs) to discuss their jet formation mechanism with the ADAF (advection-dominated accretion flow) scenario, and compare their accretion properties with Fermi BL Lacertae objects. We explored different jet mechanisms (Blandford-Znajek [BZ] model and a mixture of the BZ and Blandford-Payne, hybrid, model) within the framework of ADAF-type disc around a Kerr black hole for both LERGs and Fermi BL Lacs. Based on standard assumptions on the accretion-ejection coupling in RGs, the maximum kinetic jet and accretion power for FR 0s, FR Is, FR IIs can be, explained by an ADAF with the pure BZ mechanism or hybrid jet mechanism. In addition, for one third of the FR IIs, to account for their higher kinetic jet power than what is simply expected by the hybrid jet mechanism, the magnetic field could play an important role as in the form of magnetization-driven outflows or stronger magnetic structures, as observed in some BL Lacs with high jet powers. Similarities between BL Lacs and LERGs (e.g., accretion-ejection and clustering properties) suggest that high synchrotron peaked BL Lacs could be the beamed counterparts of FR 0s, and a potential general unification between LERGs and BL Lacs populations is discussed. However, a complete sample of BL Lacs is needed to robustly compare the jet and accretion properties with those of LERGs in the future.
format Preprint
id arxiv_https___arxiv_org_abs_2503_23607
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Accretion Properties and Jet Mechanisms for the Low-Excitation Radio Galaxies
Ye, Xu-Hong
Baldi, Ranieri D.
Chen, Yong-Yun
Bastieri, Denis
Fan, Jun-Hui
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
Radio galaxies (RGs) are a subclass of active galactic nuclei, which are suggested to be the parent populations of blazars. According to the accretion-ejection paragram, RGs can be classified into low-excitation or high-excitation radio galaxies (LERGs or HERGs). In this paper, we compiled a distance-limited ($z<0.15$) sample of 431 LERGs (Fanaroff-Riley, or FR, type 0, I, and II RGs) to discuss their jet formation mechanism with the ADAF (advection-dominated accretion flow) scenario, and compare their accretion properties with Fermi BL Lacertae objects. We explored different jet mechanisms (Blandford-Znajek [BZ] model and a mixture of the BZ and Blandford-Payne, hybrid, model) within the framework of ADAF-type disc around a Kerr black hole for both LERGs and Fermi BL Lacs. Based on standard assumptions on the accretion-ejection coupling in RGs, the maximum kinetic jet and accretion power for FR 0s, FR Is, FR IIs can be, explained by an ADAF with the pure BZ mechanism or hybrid jet mechanism. In addition, for one third of the FR IIs, to account for their higher kinetic jet power than what is simply expected by the hybrid jet mechanism, the magnetic field could play an important role as in the form of magnetization-driven outflows or stronger magnetic structures, as observed in some BL Lacs with high jet powers. Similarities between BL Lacs and LERGs (e.g., accretion-ejection and clustering properties) suggest that high synchrotron peaked BL Lacs could be the beamed counterparts of FR 0s, and a potential general unification between LERGs and BL Lacs populations is discussed. However, a complete sample of BL Lacs is needed to robustly compare the jet and accretion properties with those of LERGs in the future.
title The Accretion Properties and Jet Mechanisms for the Low-Excitation Radio Galaxies
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
url https://arxiv.org/abs/2503.23607