NGC 7468 a galaxy with an inner polar disk(5)

We present our spectroscopic observations of the galaxy NGC 7468 performed at the 6-m Special Astrophysical Observatory telescope using the UAGS long-slit spectrograph, the multipupil fiber spectrograph MPFS, and the scanning Fabry-Perot interferometer (IF

Shalyapina et al.:NGC 7468:a galaxy with an inner polar disk

5

Fig.3.Radial metallicity

distributions.

Fig.4.IFP data:(a)images in the continuum near H α;(b)an image in H α.MPFS data:the brightness distribution (c)in the continuum (λ5400−−5500˚A )and (d)in the [OIII]λ5007line.The gray scale corresponds to intensities in arbitrary units for panels (a)and (b)and to intensities in erg s −1cm 2arcsec −2˚A −1for panels (c)and (d).The pluses mark the position of the brightness maximum in the red continuum.

is V sys =2070km s −1or,after being corrected for the ro-

tation of our Galaxy,V gal =2220km s −1.The observed

velocity field is best described by the model of circular

rotation at an inclination of the galactic disk i disk ≈45◦

(which is equal to the estimate obtained from the galaxy’s

axial ratio)and that of the inner disk/ring,i ring ≈60′′.

Here,two values of the angle between the galactic disk

and the plane of the inner disk are possible:∆i ≈50◦and

∆i ≈86◦.In the first case,the orbits of the gas are unsta-

ble,and,therefore,noncircular motions must be observed in the velocity field.However,such motions have not been found,so the second value (86◦)of the angle between the galactic disk and the plane of the inner disk should be taken.The observed rotation curve of the galaxy constructed from our data (crosses)and from the HI data of Taylor et al.(1994)(triangles)is shown in Fig.6a.At R ≤3kpc,the triangle lies well below the crosses.This is most likely because the 21-cm observations have a low spatial reso-

lution (∼3kpc ).At R ≥3kpc,the discrepancy between