What is the accretion rate in NGC 4258?

Charles F. Gammie, Ramesh Narayan, Roger Blandford

Research output: Contribution to journalArticle

Abstract

We estimate the accretion rate Ṁ onto the black hole in the nucleus of NGC 4258. The result is model dependent. We find that a thin disk that is flat out to ≳2 × 103GM/c2 (M ≡ black hole mass) and that has inclination equal to that of the masing disk must have Ṁ ≃ 0.01 M yr-1 for consistency with near-infrared data. A thin disk that is warped at ∼103GM/c2 requires Ṁ ≳ 1.5 × 10-4 M yr-1 for consistency with near-infrared data. Reasonable warp models and the near-infrared data are not consistent with Ṁ as low as the 7 × 10-5α M yr-1 proposed by Neufeld & Maloney. An advection-dominated flow model combined with the X-ray data implies Ṁ ≃ 0.01 M yr-1. Consistency with a tight 22 GHz upper limit on the flux from the central source requires a transition radius of ∼(10-100)GM/c2, although the 22 GHz upper limit may be relaxed by appeal to free-free absorption. Physical conditions in the observed VLBI jet features can also be related to conditions in the inner accretion flow. We conclude with a list of observations that might further constrain Ṁ.

Original languageEnglish (US)
Pages (from-to)177-186
Number of pages10
JournalAstrophysical Journal
Volume516
Issue number1 PART 1
StatePublished - May 1 1999
Externally publishedYes

Keywords

  • Accretion, accretion disks - galaxies
  • Galaxies
  • Individual (NGC 4258) - galaxies
  • Nuclei - masers - X-rays

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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  • Cite this

    Gammie, C. F., Narayan, R., & Blandford, R. (1999). What is the accretion rate in NGC 4258? Astrophysical Journal, 516(1 PART 1), 177-186.