NEAR-IR PHOTOMETRY OF DISK GALAXIES - SEARCH FOR NUCLEAR ISOPHOTAL TWIST AND DOUBLE BARS

We present a near-IR, mainly H band, photometry of 72 nearby (d < 40 M pc) disk galaxies. The main goal of the survey was to search for isoph otal twist inside their nuclear regions. As the twist can be due in so me cases to projection effects, rather than resulting from a dynamical phenomenon, we deproject - under the simplifying assumption of a 2D g eometry - all galaxies whose disk position angle and inclination are k nown, the latter not exceeding 75 degrees. We show the ellipticity, po sition angle and surface brightness radial profiles, and discuss how a projection of 2D and 3D bars can distort the isophotes, give an illus ion of a non-existing double bar or mask a real one. We report 15 new double-barred galaxies and confirm 2 detected previously. We identify 14 additional twists not known before and we also find nuclear triaxia l structures in three SA galaxies. The frequency of Seyferts among gal axies with nuclear bars or twists is high. Since these observations ar e part of a larger survey, the interpretation of the results will be g iven in a future paper, as soon as the number of objects grows enough to permit meaningful statistics. As a secondary product, we publish st ructural parameters (length and axis ratio) of large-scale bars in ord er to extend still scarce data on bars in the near-IR.