Jet-accretion system in the nearby mJy Radio Galaxies

Abstract

It is generally thought that FRII Radio Galaxies host thin optically thick disks, while FRIs are powered by Advected Dominated Accretion Flows. The sources with an efficient engine are optically classified as High Excitation Radio Galaxies (HERGs) and those with an inefficient motor as Low Excitation Radio Galaxies (LERGs). Recently, the study of Radio Galaxies down to mJy fluxes has cast serious doubts on the LERG-FRI and HERG-FRII correspondence, revealing that many LERGs show FRII radio morphologies. The FR catalogs recently compiled by Capetti et al. (2017a,b) and Baldi et al. (2018) have allowed us to explore this issue in the local ($z\le 0.15$) mJy Universe. Our statistical study shows that the majority of nearby mJy objects are in a late stage of their life. FRII-LERGs appear more similar to the old FRI-LERGs than to the young FRII-HERGs. FRII-LERGs may be aged HERGs that, exhausted the cold fuel, have changed their accretion regime or a separate LERG class particularly efficient in launching jets. Exploiting the empirical relations which convert L${}_{[\mathrm{OIII}]}$ and L${}_{1.4\mathrm{GHz}}$ into accretion power and jet kinetic power, respectively, we observed that LERGs with similar masses and accretion rates seem to expel jets of different power. We speculate that intrinsic differences related to the black hole properties (spin and magnetic field at its horizon) can determine the observed spread in jet luminosity. In this view, FRII-LERGs should have the fastest spinning black holes and/or the most intense magnetic fluxes. On the contrary, compact LERGs (i.e. FR0s) should host extremely slow black holes and/or weak magnetic fields.

16 pages, 5 figures. Accepted for publication in ApJ

References in corpus (18)

• The Host Galaxies and Classification of Active Galactic Nuclei
• Heating Hot Atmospheres with Active Galactic Nuclei
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• The power of relativistic jets is larger than the luminosity of their accretion disks
• Measuring the kinetic power of AGN in the radio mode
• Revisiting the Fanaroff-Riley dichotomy and radio-galaxy morphology with the LOFAR Two-Metre Sky Survey (LoTSS)
• Ultra-fast outflows in radio-loud active galactic nuclei
• An XMM-Newton study of the environments, particle content and impact of low-power radio galaxies
• FR0CAT: a FIRST catalog of FR0 radio galaxies
• FRICAT: A FIRST catalog of FRI radio galaxies
• A representative survey of the dynamics and energetics of FRII radio galaxies
• Jet collimation in NGC 315 and other nearby AGN
• The Optical-Radio Mapping: the kinetic efficiency of Radio-Loud AGNs
• Relation between winds and jets in radio-loud AGN
• Radio morphology-accretion mode link in FRII low-excitation radio galaxies
• Triggering mixing and deceleration in FRI jets: a solution
• The large-scale environment of FR 0 radio galaxies
• A Chandra study of Abell 795 -- a sloshing cluster with a FR0 radio galaxy at its center

Cited by in corpus (8)

• Accretion mode versus radio morphology in the LOFAR Deep Fields
• LeMMINGs. III. The e-MERLIN Legacy Survey of the Palomar sample. Exploring the origin of nuclear radio emission in active and inactive galaxies through the [O III] -- radio connection
• Do Radio Active Galactic Nuclei Reflect X-ray Binary Spectral States?
• Radio Emission of Nearby Early-type Galaxies at Low and Very-Low Radio Luminosity Range
• VLA Snapshot Continuum Survey of FRI Quasar Candidates Selected from the LOFAR Two-Metre Sky Survey (LoTSS)
• The Accretion Properties and Jet Mechanisms for the Low-Excitation Radio Galaxies
• Linking {\it Fermi} blazars and radio galaxies through accretion and jet radiation mechanisms
• Hosts and environments: a (large-scale) radio history of AGN and star-forming galaxies