We present a near-IR, mainly H band, photometry of 72 nearby disk galaxies. The main goal of the survey was to search for isophotal twist inside their nuclear regions. As the twist can be due in some cases to projection effects, rather than resulting from a dynamical phenomenon, we deproject - under the simplifying assumption of a 2D geometry - all galaxies whose disk position angle and inclination are known, the latter not exceeding 75 degrees. We show the ellipticity, position angle and surface brightness radial profiles, and discuss how a projection of 2D and 3D bars can distort the isophotes, give an illusion 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 triaxial structures in three SA galaxies. The frequency of Seyferts among galaxies with nuclear bars or twists is high. As a secondary product, we publish structural parameters (length and axis ratio) of large-scale bars in order to extend still scarce data on bars in the near-IR. (Refer to PDF file for exact formulas).

Publication Date



Also archived in: arXiv:astro-ph/9705175 v1 21 May 1997 The authors acknowledge the participation of M. Shaw on the selection of the observed sample of galaxies. B.J. wishes to express many thanks to P. Lena, J.-P. Zahn and J. Palouˇs for their efforts in co-organizing the PhD “cotutelle” between University Paris VII and Charles University in Prague, and, especially, to F. Combes for having accepted to co-direct his PhD thesis. He also acknowledges useful discussions on data reduction techniques with J.M. Deltorn as well as the help of H. Flores with software problems. The stay of B.J. at the Paris Observatory was supported by a scholarship of the French Government.ISSN:1286-4846 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type


Department, Program, or Center

School of Physics and Astronomy (COS)


RIT – Main Campus