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Record 1 of 104085
NGC 4051 and the Nature of Narrow-Line Seyfert I Galaxies
Author and Affiliation:
Peterson, B. M.(Ohio State Univ., OH, United States)
McHardy, I. M.(Southampton Univ., United Kingdom)
Wilkes, B. J.(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States)
Abstract: We report on the results of a three-year program of coordinated X-ray and optical monitoring of the narrow-line Seyfert 1 galaxy NGC 4051. The principal results of this program are: (1) The H-beta emission line time lag and Doppler width yield a virial mass estimate of about 1.1 mission solar masses, at the extreme low end of AGN masses. A plausible adjustment for inclination effects increases this mass slightly to about 1.4 mission solar masses. (2) During the third year of this campaign, both the X-ray continuum and the He II 4686 line went into extremely low states, although the optical continuum and the H-beta broad line were both still present and variable. We suggest that the inner part of the accretion disk may have gone into an advection-dominated state, yielding little radiation from the hotter inner disk. (3) The He II 4686 line is almost five times as broad as H-beta, and it is strongly blueward asymmetric, as are the high-ionization UV lines recorded in archive spectra of NGC 4051. The data are consistent with the Balmer lines arising in a low-inclination disk-like configuration, and the high-ionization lines arising in an outflowing wind, of which we observe preferentially the near side.
Publication Date: Jan 01, 2004
Document ID:
20040055401
(Acquired May 04, 2004)
Subject Category: ASTRONOMY
Document Type: Technical Report
Contract/Grant/Task Num: NAG5-8397
Financial Sponsor: NASA Goddard Space Flight Center; Greenbelt, MD, United States
National Science Foundation; United States
Organization Source: Ohio State Univ.; OH, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: SEYFERT GALAXIES; X RAY ASTRONOMY; LIGHT (VISIBLE RADIATION); LINE SPECTRA; BALMER SERIES; H BETA LINE; ACTIVE GALACTIC NUCLEI; ASYMMETRY; STELLAR MASS; ACCRETION DISKS
Availability Source: Other Sources
Availability Notes: Abstract Only
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