Decoding the giant extragalactic radio sources

Dabhade, Pratik; Saikia, D. J.; Mahato, Mousumi

doi:10.1007/s12036-022-09898-5

Cited by 7 publications

(9 citation statements)

References 195 publications

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“…A steep SI of a core of an extended RG usually implies recurrent activity. Dabhade et al (2023) found that only about 5% of GRGs appear to show evidence of recurrent jet activity. One of the most studied GRGs with a CSS-type core is 3C 236, which shows a double-double morphology with a onesided jet on the very long baseline interferometry (VLBI) scale (Schilizzi et al 2001).…”

Section: Radio Morphologymentioning

confidence: 99%

“…The estimated values of the magnetic field and age of the SGRG are comparable to those of other GRGs analyzed so far. A summary of the literature containing all major spectral aging studies from the past four decades has recently been provided by Dabhade et al (2023). It can be seen (in their Table 3) that most of the GRGs analyzed have spectral ages <70 Myr.…”

Section: Magnetic Field and Spectral Agementioning

confidence: 99%

“…RGs can attain very large sizes, with those larger than 0.7 Mpc being referred to as giant RGs (GRGs; for references see, e.g., Kuźmicz et al 2018;Dabhade et al 2020aDabhade et al , 2020bDabhade et al , 2023. The morphology of most known GRGs falls into the FR II category, while only a small percentage (from 4.9% to 7.5%) falls into the FR I category (Ishwara-Chandra & Saikia 1999;Kuźmicz et al 2018;Dabhade et al 2020aDabhade et al , 2020b.…”

Section: Introductionmentioning

confidence: 99%

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Discovery of a 100 kpc Narrow Curved Twin Jet in the S-shaped Giant Radio Galaxy J0644+1043

Sethi,

Kuźmicz,

Jamrozy

et al. 2024

ApJ

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We report the discovery of an S-shaped morphology of the radio galaxy J0644+1043 imaged with a 30 μJy beam−1 sensitive 525 MHz broadband (bands 3 + 4) uGMRT map. Dedicated spectroscopic observations of the host galaxy carried out with the 2 m Rozhen telescope yielded a redshift of 0.0488, giving a projected linear size of the peculiar radio structure of over 0.7 Mpc. This giant radio galaxy is powered by a black hole of mass 4.1 − 2.87 + 9.39 × 10 8 M ⊙, from the vicinity of which emanate well-collimated and knotty jets, each ∼100 kpc long. The entire radio structure, presumably due to the effective jet precession, is less than 50 Myr old, has a power of ∼6 × 1024 W Hz−1 at 1.4 GHz, and has observed morphological characteristics that do not strictly conform to the traditional Fanaroff–Riley (FR) FR I or FR II categories.

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Section: Radio Morphologymentioning

confidence: 99%

Section: Magnetic Field and Spectral Agementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Discovery of a 100 kpc Narrow Curved Twin Jet in the S-shaped Giant Radio Galaxy J0644+1043

Sethi,

Kuźmicz,

Jamrozy

et al. 2024

ApJ

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“…Giant radio galaxies are a subclass of radio sources powered by supermassive black holes (SMBHs). Their large sizes are inferred to result from extensive jets reaching Mpc scales (for a review, see Dabhade et al 2023), though these jets are not of-ten detected in radio images, especially in the most common type of GRGs, the FRIIs (Fanaroff & Riley 1974). Until recently, the prevalence of GRGs was perceived to be substantially lower compared to typical radio galaxies (normal-sized), and the explanations for their immense size were largely conjectural.…”

Section: Introductionmentioning

confidence: 99%

Search and analysis of giant radio galaxies with associated nuclei (SAGAN)

Sankhyayan,

Dabhade

2024

A&A

Self Cite

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We investigated the prevalence of giant radio galaxies (GRGs), some of the largest structures powered by supermassive black holes, within supercluster environments, and the influence of such environments on their properties. Utilising two large catalogues of superclusters (401) and GRGs (1446), we established the existence of 77 GRGs (5.3%) residing in 64 superclusters (16%) within 0.05 ≤ z ≤ 0.42. Among the 77 GRGs found in superclusters, we identified ∼70% as residing within galaxy clusters. Within the subset of GRGs not located in superclusters, which constitutes 94.7% of the sample, a mere 21% are associated with galaxy clusters, while the remaining majority are situated in sparser environments. We examined the influence of differing environments, such as cluster versus non-cluster and supercluster versus non-supercluster regions, on the size of GRGs, while also exploring the driving factors behind their overall growth. Our findings show that the largest GRGs (≳3 Mpc) grow in underdense environments beyond the confines of dense environments. Moreover, we show that ∼24% of 1446 GRGs reside in galaxy clusters. We conclude that GRGs preferentially grow in sparser regions of the cosmic web and have a significantly larger median size. Finally, we demonstrate the potential of GRGs as astrophysical probes with specific cases where GRGs, exhibiting polarised emissions and located behind superclusters (acting as natural Faraday screens), were used to estimate magnetic field strengths of the supercluster environment at sub-microgauss levels.

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“…High excitation FRII systems, for example, are found to be limited to 10 million years (Turner and Shabala, 2015). Most recently, Dabhade et al (2023) have compared radio galaxies with the giant radio galaxy population, including the lifetimes of jets in FRII sources, among others. This constitutes the most exhaustive quantitative analysis of FRII lifetimes and, if these results hold up to future scrutiny, a powerful constraint on the nature of jet formation and evolution in jetted active galactic nuclei (AGN).…”

Section: Introductionmentioning

confidence: 99%

Counter-rotating black holes from FRII lifetimes

Garofalo

2023

Front. Astron. Space Sci.

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Estimates suggest that while FRII jets appear to have lifetimes constrained to hundreds of millions of years, radio galaxies with FRI jets appear to be longer lived. We illustrate the nature of this time constraint from model perspectives, showing how compatibility between theory and data match in a way suggesting a key difference between active galaxies whose engines are characterized by accretion onto co-rotating versus counter-rotating black holes. We calculate a range of timescales for counter-rotating black holes for a range of accretion rates compatible with theory which we then compare to data. The validity of these timescales constitutes the most powerful recent piece of evidence for considering counter-rotation between black holes and accretion disks in high energy astrophysics.

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Decoding the giant extragalactic radio sources

Cited by 7 publications

References 195 publications

Discovery of a 100 kpc Narrow Curved Twin Jet in the S-shaped Giant Radio Galaxy J0644+1043

Discovery of a 100 kpc Narrow Curved Twin Jet in the S-shaped Giant Radio Galaxy J0644+1043

Search and analysis of giant radio galaxies with associated nuclei (SAGAN)

Counter-rotating black holes from FRII lifetimes

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