Issue |
A&A
Volume 398, Number 2, February I 2003
|
|
---|---|---|
Page(s) | 517 - 524 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20021672 | |
Published online | 21 January 2003 |
Non-Keplerian rotation in the nucleus of NGC 1068: Evidence for a massive accretion disk?
1
Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
2
Università degli Studi di Milano, Dipartimento di Fisica, via Celoria 16, 20133 Milano, Italy
Corresponding author: G. Lodato, lodato@sns.it
Received:
9
September
2002
Accepted:
4
November
2002
The nucleus of the Seyfert galaxy NGC 1068 is believed to
host a supermassive black hole. Evidence for the presence of a
massive central object is provided by water maser emission, which
displays a linear pattern in the sky, suggestive of a rotating
disk. The rotating disk hypothesis is further strengthened by the
declining shape of the derived rotation curve. Similar maser emission
from NGC 4258 has led to a reliable estimate of the mass of the
central black hole, because in this case the rotation curve is
Keplerian. In the case of NGC 1068 the rotation curve traced by the
water maser is non-Keplerian. In this paper we provide an
interpretation of the non-Keplerian rotation in NGC 1068 by means of a
self-gravitating accretion disk model. We obtain a good fit to the
available data and derive a black hole mass . The resulting disk mass is comparable to
the black hole mass. As an interesting by-product of our fitting
procedure, we are able to estimate the viscosity parameter, which
turns out to be
, in line with some theoretical
expectations.
Key words: accretion, accretion disks / galaxies: active / galaxies: individual: NGC 1068 / galaxies: kinematics and dynamics
© ESO, 2003
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