Structural Parameters of Stellar Disks in Edge-on Galaxies from 2MASS Images

Abstract

We analyze the J, H, and Ks 2MASS images of 140 late-type edge-on galaxies selected from the RFGC catalog (which contains flat galaxies with major-to-minor axis ratio a/b > 7). The NIR scalelengths (h) and scaleheights (z0) of the stellar disks are determined for all selected galaxies. The mean relative ratios of the scaleheights of their stellar disks are 1.00:0.91:0.86 in J:H:Ks bands, respectively. We infer that the scaleheight determined from the Ks-band images is, on average, 13% larger than the extinction-free scaleheight. This difference is much larger if the scaleheights were found from the optical-band images. The relative thickness (z0/h) of the stellar disks correlates well with their deprojected central surface brightness obtained from the 2MASS images. This project was partially supported by grant RFBR 04-02-16518.