| We investigate the collapse of a gas core to a single star, the genesis of star clusters, galactic star formation rates (SFRs) and the evolution of cosmic star and galaxy formation.; First, we consider the collapse of polytropic gas cores, focusing on massive star birth. In the high-pressure environments typical of Galactic massive star-forming regions, a ∼100 M⊙ star is forged quickly in ∼105yr, at high accretion-rates of up to ∼10-3 M⊙ yr-1. Modeling protostellar evolution, we predict bolometric and ionizing luminosities, and outflow intensities. Accretion of primordial stars is often limited by the thermal pressure of an H II region. Maximum stellar masses depend on core mass, angular momentum and surface pressure. In dusty gas, ionization feedback is quenched, creating "hyper-compact" H II regions. Radiation pressure limits masses to ∼50 to 150 M⊙ , depending on core angular momentum, dust opacity and radiation field anisotropy.; The pressure-dependent collapse solution is applied to many cores to model star cluster formation. The total SFR is set from observations of Galactic protocluster outflows. Each decade of the initial mass function contributes approximately equally to the total outflow momentum. Thus, the most luminous star typically has a minor role in powering the flow. Multiple driving sources explain the poor collimation of observed flows. We identify an evolutionary sequence from the accretion-luminosity-dominated protocluster birthline to the main-sequence-luminosity-dominated cluster birthline. Feedback is considered to explore differences between Galactic and super star cluster formation.; Invoking star formation triggered by cloud collisions, we construct a model for the SFRs of galaxies and circumnuclear starbursts. The collision rate is set by disk differential rotation, with typical initial impact parameters of a few cloud tidal radii. We find Schmidt law-like relations, with deviations expected when the rotation curve is not flat. The total SFR is consistent with Galactic and starburst observations. We predict a B-band Tully-Fisher relation LB ∝ v7/3circ and smaller star formation efficiencies in higher mass clouds.; We model cosmic star and galaxy formation, specifically treating infrared observations. Normalizing at z = 0, disk evolution is set empirically, while starburst evolution is scaled to galaxy interactions and gas content. We reproduce observations of galaxy number counts and the extragalactic background, predicting high SFRs at z ∼ 3 to 4 and demonstrating the significant role of the starburst population. These merger-driven events create spheroidal systems, many of which may act as the seeds for disk formation as gas infalls. |
