Two-dimensional spectroscopy in the circumnuclear region of the Seyfert 1 ring galaxy NGC 985

We present two-dimensional optical spectroscopy of the central region (9 ". 4 x 12 ".2) of the Seyfert 1 ring galaxy NGC 985 obtained with an optical f iber system (two-dimensional Fiber ISIS System). The 95 spectra presented h ere include the H beta-[O III] lambda lambda 4959, 5007 emission lines and the Mg I b absorption lines, which permit the study of the distribution and kinematics of the ionized gas and the stars in two dimensions. In agreemen t with the results of other authors, the continuum maps show the presence o f two maxima: the bright Seyfert 1 nucleus and a second nucleus located abo ut 3 ".7 to the northwest. These observations confirm that this second nucl eus is an extragalactic object at the same redshift as that of NGC 985. The se observations indicate an anisotropic distribution of the ionized gas aro und the Seyfert nucleus. Despite this, the velocity held of the ionized gas shows a rather regular pattern, its general kinematic properties being sim ilar to those found in other unperturbed spiral Seyfert galaxies. Many of t he spectra in the region between the Seyfert and the secondary nucleus have asymmetric and relatively broad CO mi emission-line profiles. The kinemati c center of the stellar velocity field is located in the neighborhood of th e Seyfert nucleus, suggesting that this nucleus is related to the main stel lar component. Therefore, these observations support the hypothesis that NG C 985 is the result of a two-galaxy collision in which the intruder (ellipt ical or spheroidal) galaxy would be what is now the secondary nucleus, whil e the Seyfert activity is associated with the nucleus of the primary disk g alaxy. In spite of the strong disruption that defines the large-scale morph ology of NGC 985, the stellar and ionized gas kinematics do not appear sign ificantly perturbed in the circumnuclear region.