Discovery of a Subparsec Jet 4000 Radii Away from the Central Schwarzschild Engine of NGC 4258

Herrnstein, J. R.; Moran, J. M.; Greenhill, L. J.; Diamond, P. J.; Miyoshi, Makoto; Nakai, Naomasa; Inoue, Makoto

doi:10.1086/310461

Cited by 90 publications

(87 citation statements)

References 22 publications

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“…The good news is that the results have held up robustly, so that most people now feel free to concentrate on models for the warped disk, though admittedly not always the same model (Maloney et al 1996;Okazaki et al 1996) and for the pumping of the maser emission (Cao & Jiang 1997). The bad news, or perhaps just bad luck, is that an alternative, non-black hole model for the gas velocities (Burbidge & Burbidge 1997) was preceded into print by a mapping-out of the jets (Herrnstein et al 1997) that leaves little or no phase space for the alternative model. The sources's core has been seen in the infrared H and K bands, and the total luminosity at all wavelengths, which is not much more than a few # 10 7 L , , makes sense as advection-dominated accretion (Chary & Becklin 1997).…”

Section: Galaxies With Central Black Holesmentioning

confidence: 99%

Astrophysics in 1997

Trimble¹,

McFadden²

1998

PUBL ASTRON SOC PAC

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ABSTRACT. Martian marvels, a gamma-ray burster with a redshift, Galileo converses with Ganymede, a record galactic redshift of 4.92, and much else. Fiscal 1997 was definitely an exciting year for astronomers. We have tried hard to hit all the obvious highlights, but also to report more gradual progress on traditional problems of understanding planets, stars, galaxies, and the universe. Though the year was saddened by the loss of many valued colleagues, we nevertheless indulge in occasional soupçons of frivolity.

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Section: Galaxies With Central Black Holesmentioning

confidence: 99%

Astrophysics in 1997

Trimble¹,

McFadden²

1998

PUBL ASTRON SOC PAC

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“…It is clearly interacting with the dense interstellar medium (ISM ) gas in the galactic plane, evidenced by similar structures seen in H and X-ray emission (e.g., Wilson et al 2001) and a peculiar distribution of the CO line emission in the disk ( Krause et al 1990( Krause et al , 2007. Numerous investigations have been carried out on the nature of the jet in NGC 4258 (e.g., Cecil et al 1995Cecil et al , 2000Cox & Downes 1996;Herrnstein et al 1997;Vogler & Pietsch 1999;Wilson et al 2001). Wilson et al (2001) argue that the interaction could be indirect via halo gas heated by the jet and falling back onto the disk, so that the jet itself may be extraplanar.…”

Section: Introductionmentioning

confidence: 97%

Radio Continuum Jet in NGC 7479

Laine

Beck

2008

ApJ

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The barred galaxy NGC 7479 hosts a remarkable jetlike radio continuum feature: bright, 12 kpc long in projection, and hosting an aligned magnetic field. The degree of polarization is 6% Y8% along the jet and remarkably constant, which is consistent with helical field models. The radio brightness of the jet suggests strong interaction with the ISM and hence a location near the disk plane. We observed NGC 7479 at four wavelengths with the VLA and Effelsberg radio telescopes. The equipartition strength is 35Y40 G for the total and !10 G for the ordered magnetic field in the jet. The jet acts as a bright, polarized background. Faraday rotation between 3.5 and 6 cm and depolarization between 6 and 22 cm can be explained by magnetoionic gas in front of the jet, with thermal electron densities of '0.06 cm À3 in the bar and '0.03 cm À3 outside the bar. The regular magnetic field along the bar points toward the nucleus on both sides. The regular field in the disk reveals multiple reversals, probably consisting of field loops stretched by a shearing gas flow in the bar. The projection of the jet bending in the sky plane is in the sense opposite to that of the underlying stellar and gaseous spiral structure. The bending in 3D is most easily explained as a precessing jet, with an age less than 10 6 yr. Our observations are consistent with very recent triggering, possibly by a minor merger. NGC 7479 provides a unique opportunity to study interaction-triggered 15 kpc scale radio jets within a spiral galaxy.

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“…The accretion disk has an almost edge-on orientation with the radiation axis and its inclination angle is i = 83 • ± 4 • (Pringle et al 1999). A pc-scale jet closely aligns in projection on the sky with the rotation axis (Herrnstein et al 1997). Modjaz et al (2005) present an analysis of polarimetric observations at 22 GHz of the water vapor masers in NGC 4258 obtained with the VLA and the GBT.…”

Section: Magnetic Field Strength Of Ngc 4258mentioning

confidence: 95%

Magnetic fields of AGNs and standard accretion disk model: testing by optical polarimetry

Силантьев

Piotrovich

Gnedin

et al. 2009

A&A

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We have developed the method that allows us to estimate the magnetic field strength at the horizon of a supermassive black hole (SMBH) through the observed polarization of optical emission of the accreting disk surrounding SMBH. The known asymptotic formulae for the Stokes parameters of outgoing radiation are azimuthal averaged, which corresponds to an observation of the disk as a whole. We consider two models of the embedding 3D-magnetic field, the regular field, and the regular field with an additional chaotic (turbulent) component. It is shown that the second model is preferable for estimating the magnetic field in NGC 4258. For estimations we used the standard accretion disk model assuming that the same power-law dependence of the magnetic field follows from the range of the optical emission down to the horizon. The observed optical polarization from NGC 4258 allowed us to find the values 10 3 −10 4 Gauss at the horizon, depending on the particular choice of the model parameters. We also discuss the wavelength dependencies of the light polarization, and possibly applying them for a more realistic choice of accretion disk parameters.

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Discovery of a Subparsec Jet 4000 Radii Away from the Central Schwarzschild Engine of NGC 4258

Cited by 90 publications

References 22 publications

Astrophysics in 1997

Astrophysics in 1997

Radio Continuum Jet in NGC 7479

Magnetic fields of AGNs and standard accretion disk model: testing by optical polarimetry

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