13-17 Feb 2012

  • (abs, pdf) Hopkins, Why Do Stars Form In Clusters? An Analytic Model for Stellar Correlation Functions
  • (abs, pdf) Christian et al., Citizen Science: Contributions to Astronomy Research
  • (abs, pdf) Baek et al., Joint Ly{\alpha} emitters – quasars reionization constraints
  • (abs, pdf) François et al., Detailed abundances in stars belonging to ultra-faint dwarf spheroidal galaxies
  • (abs, pdf) Petri et al., Supermassive black hole ancestors
  • (abs, pdf) Qian & Wasserburg, Supernova-driven outflows and chemical evolution of dwarf spheroidal galaxies
  • (abs, pdf) Sur et al., Magnetic field amplification during gravitational collapse – Influence of initial conditions on dynamo evolution and saturation
  • (abs, pdf) Kobayashi, Elemental and isotopic abundances and chemical evolution of galaxies
  • (abs, pdf) Li et al., Cosmological Evolution of Supermassive Black Holes. II. Evidence for Downsizing of Spin Evolution

“The Birth of a Galaxy” Published

High-z dwarf galaxy
High-redshift disk dwarf galaxy

In late November, our paper, “The Birth of a Galaxy: Primordial Metal Enrichment and Stellar Populations”, was accepted for publication in The Astrophysical Journal. It was recently published in the January 20th issue.

In this paper, we followed the formation of over 300 Population III (metal-free) stars and accurately modeled the radiative feedback from their main sequence and studied the chemical enrichment from their supernovae. Our methods allowed us to follow a natural transition from Population III to Population II star formation, leading to the formation of 38 high-redshift dwarf galaxies with the most massive having M = 109 solar masses. We found that they produce a metallicity floor of 10-3 of solar metallicity in the vicinity (5-10 kpc) of their host halos. At redshift 7, about 14% of the cosmic mass is enriched above 10-6 of solar metallicity. This gives some clues on the origin of an observed metallicity floor of 10-3 in damped Lyman alpha absorbers.