A New Relation between the Absolute Magnitudes of bulges and Spiral Arm Pitch Angles (p)

摘要

In this study, we have found a new relation between the absolute magnitudes of bulges and "pitch angles" (P) (Mbulge-P). Pitch angles (P) were estimated for 40 images of galaxies from "Spitzer/IRAC" at 3.6-μm, by applying a "2D Fast Fourier Transform decomposition" method "(2DFFT)". A sample of nearly face-on spiral galaxies were selected and applied IRAF ellipse to estimate the ellipticity and major-axis position angle, and applying a 2DFFT method, the pitch angles were determined. The measurement of the absolute magnitudes of bulges is depend on a "2D (bulge - bar - disk) decomposition" program. The absolute magnitudes of bulges were estimated using the 2D multi component decomposition method.