Dynamical Status of M51

摘要: M51 enjoys a special place in the history of observational astronomy. It was first galaxy observed to have spiral structure, by Lord Rosse 1845 using 72-inch reflector at Burr Castle. Over century later, became outside Local Group be mapped extensively radio wavelengths Mathewson, van der Kruit, and Brouw [1]. Thereafter, it one galaxies CO [2], far-infrared [3], x-ray [4] wavelengths. Among important recent findings are fact that vast majority gas is molecular [5] demonstration blue light, CO, H-α, continuum, far-infrared, emission all follow nearly same exponential surface-brightness profile.