Ion

Fendt, Gene

doi:10.5840/intstudphil199729491

Cited by 37 publications

(51 citation statements)

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“…A jet viewing angle of 60 • (Cheng et al 2000;Komissarov & Lyutikov 2011) is assumed in these calculations. The expansion derived is consistent with the one expected for the jet boundary in a magnetically confined flow (Fendt 1997;Fendt & Memola 2001) with a weakly evolving poloidal magnetic field component. One can assume that the jet boundary is defined by the outermost flux surface (cf., Fendt & Memola 2001) and that the collimation of the flow begins near the light cylinder, R lc , with an initial radius of the flow of ≈10 R lc .…”

Section: Origin Of the Radio Knotssupporting

confidence: 71%

VLBI imaging of a flare in the Crab nebula: more than just a spot

Lobanov

Horns

Muxlow

2011

A&A

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We report on very long baseline interferometry (VLBI) observations of the radio emission from the inner region of the Crab nebula, made at 1.6 GHz and 5 GHz after a recent high-energy flare in this object. The 5 GHz data have provided only upper limits of 0.4 milli-Jansky (mJy) on the flux density of the pulsar and 0.4 mJy/beam on the brightness of the putative flaring region. The 1.6 GHz data have enabled imaging the inner regions of the nebula on scales of up to ≈40 . The emission from the inner "wisps" is detected for the first time with VLBI observations. A likely radio counterpart (designated "C1") of the putative flaring region observed with Chandra and HST is detected in the radio image, with an estimated flux density of 0.5 ± 0.3 mJy and a size of 0 . 2-0 . 6. Another compact feature ("C2") is also detected in the VLBI image closer to the pulsar, with an estimated flux density of 0.4 ± 0.2 mJy and a size smaller than 0 . 2. Combined with the broad-band SED of the flare, the radio properties of C1 yield a lower limit of ≈0.5 mG for the magnetic field and a total minimum energy of 1.2 × 10 41 erg vested in the flare (corresponding to using about 0.2% of the pulsar spin-down power). The 1.6 GHz observations provide upper limits for the brightness (0.2 mJy/beam) and total flux density (0.4 mJy) of the optical Knot 1 located at 0 . 6 from the pulsar. The absolute position of the Crab pulsar is determined, and an estimate of the pulsar proper motion (μ α = −13.0 ± 0.2 mas/yr, μ δ = +2.9 ± 0.1 mas/yr) is obtained.

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Section: Origin Of the Radio Knotssupporting

confidence: 71%

VLBI imaging of a flare in the Crab nebula: more than just a spot

Lobanov

Horns

Muxlow

2011

A&A

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“…• (Fendt 1997). Such a narrow beaming is supported by the results of the ROTSE (Robotical Optical Transient Search Experiment) telescope (see http://www.umich.edu/rotse/ for more details).…”

Section: The Precessing Jetmentioning

confidence: 82%

Explaining the light curves of gamma-ray bursts with a precessing jet

Zwart

Lee

1999

Astron. Astrophys. Suppl. Ser.

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“…It seems therefore quite interesting whether in the case of AGN centrifugal acceleration by rotating jet magnetosphere may potentially fill this gap by providing pre-accelerated seed particles. For an analytical treatment, we consider the following simplified model: motivated by MHD-scenarios for the origin of jets via rotating jet magnetospheres [2,3,5] (see Fig. 1) a projected two-dimensional model topology is applied where the magnetic field is supposed to rotate rigidly with a fraction of the rotational velocity of the black hole [5].…”

Section: Introductionmentioning

confidence: 99%

Test particle acceleration by rotating jet magnetospheres

Rieger¹,

Mannheim²

2001

AIP Conference Proceedings

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Abstract. Centrifugal acceleration of charged test particles at the base of a rotating jet magnetosphere is considered. Based on an analysis of forces we derive the equation for the radial accelerated motion and present an analytical solution. It is shown that for particles moving outwards along rotating magnetic field lines, the energy gain is in particular limited by the breakdown of the bead-on-the-wire approximation which occurs in the vicinity of the light cylinder r L . The corresponding upper limit for the maximum Lorentz factor γ max for electrons scales ∝ B 2/3 r 2/3 L , with B the magnetic field strength at r L , and is at most of the order of a 10 2 − 10 3 for the conditions regarded to be typical for BL Lac objects. Such values suggest that this mechanism may provide pre-accelerated seed particles which are required for efficient Fermi-type particle acceleration at larger scales in radio jets.

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Ion

Cited by 37 publications

References 0 publications

VLBI imaging of a flare in the Crab nebula: more than just a spot

VLBI imaging of a flare in the Crab nebula: more than just a spot

Explaining the light curves of gamma-ray bursts with a precessing jet

Test particle acceleration by rotating jet magnetospheres

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