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What Is the Accretion Rate in NGC 4258?

Gammie, Charles F. and Narayan, Ramesh and Blandford, Roger (1999) What Is the Accretion Rate in NGC 4258? Astrophysical Journal, 516 (1). pp. 177-186. ISSN 0004-637X. doi:10.1086/307089.

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We estimate the accretion rate M 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 × 10^3GM/c^2 (M ≡ black hole mass) and that has inclination equal to that of the masing disk must have M ≃ 0.01 M☉ yr^(-1) for consistency with near-infrared data. A thin disk that is warped at ~103GM/c2 requires M ≳ 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 M as low as the 7 × 10^(-5) α M☉ yr^(-1) proposed by Neufeld & Maloney. An advection-dominated flow model combined with the X-ray data implies M ≃ 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 M.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Narayan, Ramesh0000-0002-1919-2730
Blandford, Roger0000-0002-1854-5506
Additional Information:© 1999 The American Astronomical Society. Received 1998 June 26; accepted 1998 December 8. This work was supported in part by NSF grants AST 94-23209 and AST 95-29170 and NASA grants NAG 5-2837 and NAG5-7007. We thank A. Esin for assistance with the ASCA data, and R. Chary, L. Greenhill, J. Herrnstein, J.-P. Lasota, and the referee for helpful comments.
Funding AgencyGrant Number
NSFAST 94-23209
NSFAST 95-29170
NASANAG 5-2837
Subject Keywords:accretion, accretion disks - galaxies : individual (NGC 4258) - galaxies : nuclei - masers - X-rays: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20190603-095044083
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Official Citation:Charles F. Gammie et al 1999 ApJ 516 177
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96031
Deposited By: Tony Diaz
Deposited On:03 Jun 2019 18:41
Last Modified:16 Nov 2021 17:17

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