On disks and jet(s) in the defunct quasar M 87

Camenzind, M.

doi:10.1007/bfb0106437

Cited by 135 publications

(210 citation statements)

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“…We next investigate the interpretation of a hydrodynamic or magnetized jet instability for a helical structure (Camenzind 1986; Hardee 1987). We used the simple analytic model described in Steffen et al (1995) to fit to the helical jet trajectory in 3C 48.…”

Section: Kinematics Of the Radio Jetmentioning

confidence: 99%

Kinematics of the parsec-scale radio jet in 3C 48

An¹,

Hong²,

Hardcastle³

et al. 2009

Monthly Notices of the Royal Astronomical Society

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???The definitive version is available at www3.interscience.wiley.com '. Copyright Royal Astronomical SocietyWe present results on the compact steep-spectrum quasar 3C 48 from observations with the Very Long Baseline Array (VLBA), the Multi-Element Radio Linked Interferometer Network (MERLIN) and the European Very long baseline interferometry (VLBI) Network (EVN) at multiple radio frequencies. In the 1.5-GHz VLBI images, the radio jet is characterized by a series of bright knots. The active nucleus is embedded in the southernmost VLBI component A, which is further resolved into two sub-components A1 and A2 at 4.8 and 8.3 GHz, respectively. A1 shows a flat spectrum and A2 shows a steep spectrum. The most strongly polarized VLBI components are located at component C ??? 0.25 arcsec north of the core, where the jet starts to bend to the north-east. The polarization angles at C show gradual changes across the jet width at all observed frequencies, indicative of a gradient in the emission-weighted intrinsic polarization angle across the jet and possibly a systematic gradient in the rotation measure; moreover, the percentage of polarization increases near the curvature at C, likely consistent with the presence of a local jet???interstellar-medium interaction and/or changing magnetic-field directions. The hot spot B shows a higher rotation measure, and has no detected proper motion. These facts provide some evidence for a stationary shock in the vicinity of B. Comparison of the present VLBI observations with those made 8.43 yr ago suggests a significant northward motion for A2 with an apparent transverse velocity ??app= 3.7 ?? 0.4c . The apparent superluminal motion suggests that the relativistic jet plasma moves at a velocity of ???0.96c if the jet is viewed at an inclination angle less than 20?? . A simple precessing jet model and a hydrodynamical isothermal jet model with helical-mode Kelvin???Helmholtz instabilities are used to fit the oscillatory jet trajectory of 3C 48 defined by the bright knot

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Section: Kinematics Of the Radio Jetmentioning

confidence: 99%

Kinematics of the parsec-scale radio jet in 3C 48

An¹,

Hong²,

Hardcastle³

et al. 2009

Monthly Notices of the Royal Astronomical Society

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“…The total nuclear (disk and jet) bolometric luminosity of M 87 has been estimated to be of order L bol ∼ 10 42 erg/s or less (Reynolds et al 1996;Owen et al 2000), indicating that M 87 is a highly underluminous source with l e ≤ 3 × 10 −6 , where l e = L bol /L Edd and L Edd is the Eddington luminosity. This has led to the proposal that M 87 is a prototype galaxy, where accretion occurs in a two-temperature, advective-dominated (ADAF) mode characterized by an intrinsically low radiative efficiency (Reynolds et al 1996;Camenzind 1999;Di Matteo et al 2003). Magnetic flux dragged inwards may then build up a rigidly rotating, dipolar magnetosphere, along which disk plasma can be centrifugally accelerated to (bulk) outflow Lorentz factors of Γ b (5−10).…”

Section: Phenomenological Backgroundmentioning

confidence: 99%

“…Magnetic flux dragged inwards may then build up a rigidly rotating, dipolar magnetosphere, along which disk plasma can be centrifugally accelerated to (bulk) outflow Lorentz factors of Γ b (5−10). The generated light cylinder scale is likely to be of order r L ∼ 5 r s (Camenzind & Krockenberger 1992;Fendt 1997;Camenzind 1999;cf. also Fendt & Memola 2001, for higher r L if differential rotation is important).…”

Section: Phenomenological Backgroundmentioning

confidence: 99%

“…Here we explore the possibility that centrifugal acceleration of electrons, occurring in the vicinity of a sub-Eddington accreting black hole system, could via inverse Compton processes lead to variable VHE gamma-ray emission. Centrifugal acceleration of plasma flows by rotating magnetospheres has been widely discussed, both in the context of pulsar emission models (e.g., Gold 1969; Machabeli & Rogava 1994;Chedia et al 1996;Gangadhara 1996;Bogovalov 1997;Contopolous et al 1999;Machabeli et al 2005;Thomas & Gangadhara 2007) and in the context of relativistic jet formation (e.g., Blandford & Payne 1982;Fendt 1997;Camenzind 1999;Meier et al 2001). Detailed MHD simulations, for example, indicate that centrifugally-driven outflows from AGNs could reach bulk Lorentz factors Γ b ∼ 10.…”

Section: Introductionmentioning

confidence: 99%

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Variable VHE gamma-ray emission from non-blazar AGNs

Rieger¹,

Aharonian

2007

A&A

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Context. The observation of rapidly variable very high energy (VHE) gamma-rays from non-aligned active galactic nuclei (AGNs), as reported from M 87, proves challenging for conventional theoretical acceleration and emission models. Aims. Motivated by recent work on pulsar-type particle acceleration in M 87 (Neronov & Aharonian 2007, ApJ, 671, 85), we reexamine the centrifugal acceleration of particles by rotating jet magnetospheres in the vicinity of accreting supermassive black hole systems and analyze the energy constraints imposed for highly underluminous systems. Methods. The maximum Lorentz factor for centrifugally accelerated electrons in the presence of inverse Compton losses, and the associated characteristic variability time scale, are determined. Applications are presented for conditions expected to be present in the radio galaxy M 87, assuming accretion onto the central black hole to occur in an advection-dominated (ADAF) mode. Conclusions. Centrifugal acceleration could provide a natural explanation for the challenging VHE emission features in M 87. Our results suggest that some advection-dominated accreting (non-blazar) AGNs could well be observable VHE emitting sources.

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“…M87 has thus often been considered to be a prototype galaxy for the presence of a radiatively inefficient accretion flow (RIAF), e.g. [17,18].…”

Section: The Central Engine In M87mentioning

confidence: 99%

TeV emission and jet formation in M87

Rieger¹,

Levinson²

2011

Proceedings of 25th Texas Symposium on Relativistic Astrophysics — PoS(Texas 2010)

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The detection of rapidly variable TeV emission on timescales of ∼ 1 day in M87 implies a source size of a few Schwarzschild radii r s , and suggests that the TeV emission may originate from unscreened electric fields in the black hole magnetospheres. The presence of the VLBA jet, on the other hand, indicates that a force-free (ideal) MHD flow is established on scales < 50 r s . We show that inverse Compton scattering of ambient photons by electrons accelerated in the gap can initiate a pair cascade above the gap, that results in a sufficiently large multiplicity to ensure a force-free flow. Photons having energies below a few TeV can escape freely. The VHE power radiated by the gap can easily account for the luminosity of the TeV source detected by, e.g., H.E.S.S. Intermittencies of the cascade process will give rise to the observed variability of the TeV emission, and the resultant force-free outflow, as indicated by the morphological changes of the VLBA jet.

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On disks and jet(s) in the defunct quasar M 87

Cited by 135 publications

References 30 publications

Kinematics of the parsec-scale radio jet in 3C 48

Kinematics of the parsec-scale radio jet in 3C 48

Variable VHE gamma-ray emission from non-blazar AGNs

TeV emission and jet formation in M87

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