Star-forming complexes in a sample of spiral and irregular galaxies.
ELMEGREEN D.M. and SALZER J.J.
Abstract (from CDS):
Over 300 star-forming complexes in 11 intermediate- and late-type spiral and irregular galaxies have been observed in the B, I, and Hα bands to determine their luminosity functions, ages, sizes, and masses. The total Hα luminosity from complexes compared with the total galaxy Hα luminosity ranges from 20% to 70%, but the percentage is nearly constant at 7% in the B band for most galaxies. A comparison of the colors and luminosities of the complexes with published cluster evolutionary models suggests that the complexes range in age from a few times 106 yr to nearly 109 yr; the majority have ages of less than 1 to 2x107 yr. The complex masses range from 104 to 107M☉. The luminosity functions for the complexes follow a power law with an exponent of approximately -2; late-type galaxies have slightly shallower slopes than intermediate-type galaxies. The sizes of the largest complexes in each galaxy scale approximately with the square root of the galaxy luminosity, confirming previous studies. The complexes may have a fractal size distribution that is consistent with values predicted by theoretical turbulence models of the interstellar medium.
Galaxies: Irregular - Galaxies: Spiral - ISM: H II Regions