Measurements of Equivalent Thicknesses of 3-dimensional PGC-54-like Spiral Galactic Disks

With the improved Pengʹs method, we have made the image processing and spiral arm fitting of the newly released spiral galactic images of Sloan Digital Sky Survey (SDSS), and obtained the equivalent thicknesses of galactic disks, as well as the tangential angles of spiral arms of 73 spiral galaxies. These physical quantities are very important for future studies on the properties of spiral galaxies.