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Morphology of the nuclear disk in M 87

  • Z. I. Tsvetanov
  • M. G. Allen
  • H. C. Ford
  • R. J. Harms
Conference paper
Part of the Lecture Notes in Physics book series (LNP, volume 530)

Abstract

A deep, fully sampled diffraction limited (FWHM ∼ 70 mas) narrowband image of the central region in M 87 was obtained with the Wide Filed and Planetary Camera 2 of the Hubble Space Telescope using the dithering technique. The Hα+[N ii] continuum subtracted image reveals a wealth of details in the gaseous disk structure described earlier by Ford et al. (1994). The disk morphology is dominated by a well defined three-arm spiral pattern. In addition, the major spiral arms contain a large number of small “arclets” covering a range of sizes (0″.1–0″.3=10–30 pc). The overall surface brightness profile inside a radius ∼ 1″.5 (100 pc) is well represented by a power-law I(μ) ∼ μ−1.75, but when the central ∼ 40 pc are excluded it can be equally well fit by an exponential disk. The major axis position angle remains constant at about PAdisk ∼ 6° for the innermost ∼ 1″, implying the disk is oriented nearly perpendicular to the synchrotron jet (PAjet ∼ 291°). At larger radial distances the isophotes twist, reflecting the gas distribution in the filaments connecting to the disk outskirts. The ellipticity within the same radial range is e=0.2 − 0.4, which implies an inclination angle of i ∼ 35°. The sense of rotation combined with the dust obscuration pattern indicate that the spiral arms are trailing.

Keywords

Hubble Space Telescope Central Black Hole Gaseous Disk Disk Morphology Large Radial Distance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 1999

Authors and Affiliations

  • Z. I. Tsvetanov
    • 1
  • M. G. Allen
    • 1
    • 2
  • H. C. Ford
    • 1
    • 3
  • R. J. Harms
    • 4
  1. 1.Johns Hopkins UniversityBaltimoreUSA
  2. 2.Mount Stromlo and Siding Spring ObservatoriesAustralia
  3. 3.Space Telescope Science InstituteBaltimoreUSA
  4. 4.RJH ScientificAlexandriaUSA

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