射电天文研究组知识库

The objective of this work is to obtain the disk thickness and spiral arm structure of M31. The method to estimate the thickness of galactic disk is based on using Poisson's equation for the logarithmical matter density in three-dimensional disk galaxies. We use new infrared image of M31 at 24 mu m taken with the Multiband Imaging Photometer for Spitzer (MIPS). Far infrared images would be free of blurring by the bright bulge, so that the spiral arms can be traced inwards to smaller radii (the forbidden radii). We investigate the fitting of a two-armed (a- and b-arm) spiral structure of M31 by logarithmical spirals. From a-arm structure, we acquire the disk inclination gamma(a) = 74.5 +/- 1.5 degrees, and from b-arm structure, gamma(b) = 70.3 +/- 2.0 degrees. The mean values for the forbidden radius (r) over bar (0), the winding parameter (Lambda) over bar, and the disk thickness (H) over bar are 2.82 +/- 0.23 kpc, 12.49 +/- 1.50, and 0.45 +/- 0.09 kpc, respectively. (C) 2013 Elsevier B.V. All rights reserved.