Open AccessGas motions in the plane of the spiral galaxy NGC 3631
Author(s) -
Fridman A. M.,
Khoruzhii O. V.,
Polyachenko E. V.,
Zasov A. V.,
Sil'Chenko O. K.,
Moiseev A. V.,
Burlak A. N.,
Afanasiev V. L.,
Dodonov S. N.,
Knapen J. H.
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04218.x
Subject(s) - physics , grand design spiral galaxy , astrophysics , barred spiral galaxy , spiral galaxy , unbarred spiral galaxy , irregular galaxy , galaxy , spiral (railway) , vector field , interacting galaxy , lenticular galaxy , astronomy , elliptical galaxy , mathematical analysis , mathematics , mechanics
The velocity field of the nearly face‐on galaxy NGC 3631, derived from observations in the H α line and H i radio line, is analysed to study perturbations related to the spiral structure of the galaxy. We confirm our previous conclusion that the line‐of‐sight velocity field gives evidence of the wave nature of the observed two‐armed spiral structure. Fourier analysis of the observed velocity field is used to determine the location of corotation of the spiral structure of this galaxy, and the radius of corotation R c is found to be about 42 arcsec, or 3.2 kpc. The vector velocity field of the gas in the plane of the disc is restored, and, taking into account that we previously investigated vertical motions, we now have a full three‐dimensional gaseous velocity field of the galaxy. We show clear evidence of the existence of two anticyclonic and four cyclonic vortices near corotation in a frame of reference rotating with the spiral pattern. The centres of the anticyclones lie between the observed spiral arms. The cyclones lie close to the observed spirals, but their centres are shifted from the maxima in brightness.