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. https://resolver.caltech.edu/CaltechAUTHORS:20190603-095044083
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Abstract
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.
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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. | ||||||||||
Group: | TAPIR | ||||||||||
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Subject Keywords: | accretion, accretion disks - galaxies : individual (NGC 4258) - galaxies : nuclei - masers - X-rays: galaxies | ||||||||||
Issue or Number: | 1 | ||||||||||
DOI: | 10.1086/307089 | ||||||||||
Record Number: | CaltechAUTHORS:20190603-095044083 | ||||||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20190603-095044083 | ||||||||||
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 | ||||||||||
Collection: | CaltechAUTHORS | ||||||||||
Deposited By: | Tony Diaz | ||||||||||
Deposited On: | 03 Jun 2019 18:41 | ||||||||||
Last Modified: | 16 Nov 2021 17:17 |
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