A chemically decoupled nucleus and structure of the nuclear region in the S0 galaxy NGC 4036

We present the results of a comprehensive spectrophotometric study of the c entral region in the regular lenticular galaxy NGC 4036 with two spectrogra phs of the 6-m telescope. The unresolved nucleus of NGC 4036 is shown to be chemically decoupled: [Mg/Fe] = +0.3 at the very center, whereas in the im mediate vicinity of its nucleus, this ratio abruptly drops to +0.1 and does not change further along the radius. A study of isophotal morphology in co mbination with a kinematic analysis has proven that the rotation of stars a t the NGC 4036 center is axisymmetric. However, the major-axis turn within R < 5<double prime> should be considered real. We interpret this turn as ev idence for the existence of a tilted circumnucelar stellar disk with a radi us of similar to 250 pc in NGC 4036. The NGC 4036 bulge may be triaxial, an d the ionized gas at the galactic center is then concentrated toward the pr incipal plane of the ellipsoidal potential. (C) 2001 MAIK "Nauka/Interperio dica".