Issue |
A&A
Volume 430, Number 1, January IV 2005
|
|
---|---|---|
Page(s) | 67 - 81 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:200400087 | |
Published online | 12 January 2005 |
The orientation parameters and rotation curves of 15 spiral galaxies *,**
1
Institute of Astronomy of the Russian Academy of Science, 48, Pyatnitskaya St., Moscow 109017, Russia
2
Sternberg Astronomical Institute, Moscow State University, University prospect 13, Moscow 119992, Russia
3
Special Astrophysical Observatory, Nizhnij Arkhyz, Karachaevo-Cherkesia 357147, Russia
4
Troitsk Institute for Innovation and Thermonuclear Researches, Troitsk, Moscow reg. 142092, Russia
5
Guest investigator of the UK Astronomy Data Centre
6
Isaac Newton Institute of Chile, Moscow Branch, Russia
Received:
13
December
2002
Accepted:
1
September
2004
We analyzed ionized gas motion and disk orientation
parameters for 15 spiral galaxies. Their velocity fields were
measured with the Hα emission line by using the Fabry-Perot
interferometer at the 6 m telescope of SAO RAS. Special attention
is paid to the problem of estimating the position angle of the
major axis and the inclination (i) of a disk, which
strongly affect the derived circular rotation velocity. We
discuss and compare different methods of obtaining these
parameters from kinematic and photometric observations, taking
into account the presence of regular velocity (brightness)
perturbations caused by spiral density waves. It is shown that
the commonly used method of tilted rings may lead to systematic
errors in the estimation of orientation parameters (and hence of
circular velocity) being applied to galaxies with an ordered
spiral structure. Instead we recommend using an assumption of
constancy of i and PA0 along a radius, to estimate these
parameters. For each galaxy of our sample we present
monochromatic Hα- and continuum maps, velocity fields of
ionized gas, and the mean rotation curves in the frame of a model
of pure circular gas motion. Significant deviations from circular
motion with amplitudes of several tens of
(or higher) are
found in almost all galaxies. The character and possible nature of
the non-circular motion are briefly discussed.
Key words: galaxies: kinematics and dynamics / galaxies: spiral
© ESO, 2005
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.