• Title/Summary/Keyword: galaxies: jets

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The Development of the Black Hole Magnetosphere Model in the Last Thirty Years (블랙홀 자기권 모델 30년)

  • PARK SEOK JAE
    • Publications of The Korean Astronomical Society
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    • v.15 no.1
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    • pp.1-13
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    • 2000
  • Since Goldreich and Julian's pioneering work in 1969, the pulsar magnetosphere theory has been dramatically developed for theorists to possess an elegant axisymmetric, stationary model. Based on this development the black hole magnetosphere theory has also been established in the last 30 years. Such theoretical developments will be reviewd equation by equation in this paper.

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PLASMA VELOCITIES IN THE NONSTATIONARY BLACK HOLE MAGNETOSPHERE (시간에 따라 변하는 블랙홀 자기권의 플라즈마 속도)

  • PARK SEOK JAE
    • Publications of The Korean Astronomical Society
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    • v.17 no.1
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    • pp.7-10
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    • 2002
  • In the earlier papers we analyzed the axisymmetric, nonstationary electrodynamics of the central black hole and a surrounding thin accretion disk in an active galactic nucleus. Based on those papers we analyze the axisymmetric, nonstationary force-free black hole magnetosphere and the motion of the plasma. We concentrate on deriving the relations between the velocity components of the plasma and those of the accreting magnetic field lines. We conclude that the former are given by the sum of the latter and the magnetic field terms.

STATIONARY, AXISYMMETRIC BLACK HOLE MAGNETO SPHERES IN OBLATE SPHEROIDAL COORDINATES (축대칭을 만족하고 시간에 따라 변하지 않는 블랙홀 자기권의 편원 좌표계적 기술)

  • PARK SEOK JAE;FLETCHER ANDRE B.
    • Publications of The Korean Astronomical Society
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    • v.16 no.1
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    • pp.11-14
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    • 2001
  • In this paper, we simplify the equations of the Macdonald-Thome black hole magnetosphere. Our major assumption is that the 3-D electric and magnetic flux isosurfaces respectively form families of confocal oblate spheroids and hyperboloids. As a result, the magnetospheric equations are greatly simplified, and may provide a useful framework for instances when rigorous, theoretical approaches are not necessary.

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NEW EQUATIONS FOR THE ENTROPY INCREASE AND THE ANGULAR MOMENTUM-ENERGY EQUATION OF A BLACK HOLE (새로운 블랙흘 엔트로피 증가, 각운동량-에너지 추출 방정식)

  • Park, Seok-Jae
    • Publications of The Korean Astronomical Society
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    • v.18 no.1
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    • pp.11-14
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    • 2003
  • In the earlier papers we analyzed the axisymmetric, nonstationary electrodynamics of the central black hole and a surrounding thin accretion disk in an active galactic nucleus. Based on those papers we analyze the axisymmetric, nonstationary force-free black hole magnetosphere and the motion of the plasma. We concentrate on deriving the totally new equations for the entropy incrrease and the angular momentum, energy extraction of the black hole.

THE NONSTATIONARY 'GRAD-SHAFRANOV EQUATIONS' IN THE BLACK HOLE MAGNETOSPHERES (시간에 따라 변하는 블랙흘 자기권의 'GRAD-SHAFRANOV 방정식')

  • Park, Seok-Jae;Lee, Tae-Hyeong
    • Publications of The Korean Astronomical Society
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    • v.18 no.1
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    • pp.15-20
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    • 2003
  • In the earlier papers we analyzed the axisymmetric, nonstationary electrodynamics of the central black hole and a surrounding thin accretion disk in an active galactic nucleus. Based on those papers we analyze the axisymmetric, nonstationary black hole magnetosphere in this paper. We concentrate on deriving the ‘Grad-Shafranov equations’; both in the force-free and non-force-free cases. In the time-independent limit our equations naturally coincide with stationary equations as they should.

SIMULATING NONTHERMAL RADIATION FROM CLUSTER RADIO GALAXIES

  • TREGILLIS I. L.;JONES T. W.;RYU DONGSU
    • Journal of The Korean Astronomical Society
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    • v.37 no.5
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    • pp.509-515
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    • 2004
  • We present results from an extensive synthetic observation analysis of numerically-simulated radio galaxy (RG) jets. This analysis is based on the first three-dimensional simulations to treat cosmic ray acceleration and transport self-consistently within a magnetohydrodynamical calculation. We use standard observational techniques to calculate both minimum-energy and inverse-Compton field values for our simulated objects. The latter technique provides meaningful information about the field. Minimum-energy calculations retrieve reasonable field estimates in regions physically close to the minimum-energy partitioning, though the technique is highly susceptible to deviations from the underlying assumptions. We also study the reliability of published rotation measure analysis techniques. We find that gradient alignment statistics accurately reflect the physical situation, and can uncover otherwise hidden information about the source. Furthermore, correlations between rotation measure (RM) and position angle (PA) can be significant even when the RM is completely dominated by an external cluster medium.

SEDs and Beaming Effect for Fermi Blazars

  • Fan, Jun-Hui;Yang, Jiang-He;Liu, Yi;Yuan, Yu-Hai;Lin, Cao;Xiao, Hu-Bing
    • Journal of Astronomy and Space Sciences
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    • v.33 no.2
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    • pp.105-108
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    • 2016
  • In this work, based on our previous calculations of spectral energy distributions for a sample of Fermi blazars (Fan et al. 2015a), we calculated the radio loudness and performed correlation analyses. Our analysis results show that radio loudness is closely anti-correlated with synchrotron peak frequency and positively correlated with gamma-ray luminosity, suggesting that the gamma-ray emissions are strongly beamed.

LOW-LEVEL RADIO EMISSION FROM RADIO GALAXIES AND IMPLICATIONS FOR THE LARGE SCALE STRUCTURE

  • KRISHNA GOPAL;WIITA PAUL J.;BARAI PARAMITA
    • Journal of The Korean Astronomical Society
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    • v.37 no.5
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    • pp.517-525
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    • 2004
  • We present an update on our proposal that during the 'quasar era' (1.5 $\le$ z $\le$ 3), powerful radio galaxies could have played a major role in the enhanced global star-formation, and in the widespread magnetization and metal pollution of the universe. A key ingredient of this proposal is our estimate that the true cosmological evolution of the radio galaxy population is likely to be even steeper than what has been inferred from flux-limited samples of radio sources with redshift data, when an allowance is made for the inverse Compton losses on the cosmic microwave background which were much greater at higher redshifts. We thus estimate that a large fraction of the clumps of proto-galactic material within the cosmic web of filaments was probably impacted by the expanding lobes of radio galaxies during the quasar era. Some recently published observational evidence and simulations which provide support for this picture are pointed out. We also show that the inverse Compton x-ray emission from the population of radio galaxies during the quasar era, which we inferred to be largely missing from the derived radio luminosity function, is still only a small fraction of the observed soft x-ray background (XRB) and hence the limit imposed on this scenario by the XRB is not violated.