Formation of OB Associations in Galaxies
arXiv:0705.0634 · doi:10.1086/519375
Abstract
We consider the formation of OB associations from two perspectives: (a) the fractional gas consumption in star formation,epsilon, per dynamical time scale t_dyn in a galaxy, and (b) the origin of the so-called Kennicutt-Schmidt law that the rate of star formation per unit area is proportional to a power, alpha, of the surface density in HI and H_2 gas when certain thresholds are crossed. The empirical findings that epsilon is approximately 0.01 and alpha is approximately 1.4 or 1.5 have simple explanations if the rate of star formation is magnetically regulated. An empirical test of the ideas resides in an analysis of why giant OB associations are ``strung out like pearls along the arms" of spiral galaxies.
The Astrophysical Journal Letters, in press
References in corpus (14)
- Interstellar Turbulence I: Observations and Processes
- A General Theory of Turbulence-Regulated Star Formation, From Spirals to ULIRGs
- Dissipation in Compressible MHD Turbulence
- Kinetic Energy Decay Rates of Supersonic and Super-Alfvenic Turbulence in Star-Forming Clouds
- Star Formation Thresholds in Galactic Disks
- The mass function of dense molecular cores and the origin of the IMF
- A Super-Alfvenic Model of Dark Clouds
- Formation and Fragmentation of Gaseous Spurs in Spiral Galaxies
- Formation of Spiral-Arm Spurs and Bound Clouds in Vertically Stratified Galactic Gas Disks
- Global Modeling of Spur Formation in Spiral Galaxies
- Spurs and feathering in spiral galaxies
- Correlation Between Gas and Dust in Molecular Clouds: L977
- Branch, Spur, and Feather Formation in Spiral Galaxies
- Nonlinear Criterion for the Stability of Molecular Clouds
Cited by in corpus (8)
- The Star Formation Law in Atomic and Molecular Gas
- The Big Problems in Star Formation: the Star Formation Rate, Stellar Clustering, and the Initial Mass Function
- Clump morphology and evolution in MHD simulations of molecular cloud formation
- Why are most molecular clouds not gravitationally bound?
- Molecular Cloud Evolution IV: Magnetic Fields, Ambipolar Diffusion, and the Star Formation Efficiency
- An Evolutionary Model For Submillimeter Galaxies
- Interstellar MHD Turbulence and Star Formation
- The Star Formation Law in a Multifractal ISM