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Abstract We point out the dominant importance of plasma injection effects of relativistic winds from pulsars and black holes. We demonstrate that outside the light cylinder, the magnetically dominated outflows sliding along the helical magnetic field move nearly radially with very large Lorentz factors,γ0≫ 1, imprinted into the flow during pair production within the gaps. Only at larger distances,r≥γ0(c/Ω), does MHD acceleration Γ ∝rtake over. As a result, Blandford–Znajek (BZ)-driven outflows produce spine-brightened images. The best-resolved case of the jet in M87 shows both edge-brightened features, as well as weaker spine-brightened features. Only the spine-brightened component can be BZ driven/originate from the black hole's magnetosphere.
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Spindown of Pulsars Interacting with Companion Winds: The Impact of Magnetospheric Compression
Abstract Pulsars in binary systems with strong companion winds can have the magnetopause separating their magnetosphere from the wind located well within their light cylinder. This bow-like enclosure effectively creates a waveguide that confines the pulsar’s electromagnetic fields and can significantly alter its spindown. In this paper, we study the spindown of compressed pulsar magnetospheres in such systems. We parameterize the confinement as the ratio between the equatorial position of the magnetopause (or standoff distance)Rmand the pulsar’s light cylinderRLC. Using particle-in-cell simulations, we quantify the pulsar spindown for a range of compressions,Rm/RLC= 1/3–1, and inclination angles,χ= 0°…90°, between magnetic and rotation axes. Our strongly confined models (Rm/RLC= 1/3) show two distinct limits. Forχ= 0°, the spindown of a compressed pulsar magnetosphere is enhanced by approximately a factor of three compared to an isolated pulsar due to the increased number of open magnetic field lines. Conversely, forχ= 90°, the compressed pulsar spins down at less than 40% of the rate of an isolated reference pulsar due to the mismatch between the pulsar wind stripe wavelength and the waveguide size. We apply our analysis to the 2.77 s oblique rotator (χ= 60°) in the double-pulsar system PSR J0737-3039. With the numerically derived spindown estimate, we constrain its surface magnetic field toB*≈ (7.3 ± 0.2) × 1011G. We discuss the time modulation of its period derivative, the effects of compression on its braking index, and implications for the radio eclipse in PSR J0737-3039.
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- Award ID(s):
- 2206607
- PAR ID:
- 10544680
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 973
- Issue:
- 2
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 147
- Size(s):
- Article No. 147
- Sponsoring Org:
- National Science Foundation
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