Theory Group : Galactic Evolution : ISM and Star Formation
The minimum stellar metallicity observable in the Galaxy astro-ph
Mixing of Primordial Gas in Lyman Break Galaxies astro-ph
Does Radiative Feedback by the First Stars Promote or Prevent Second Generation Star Formation? astro-ph
Volker Bromm, Chalence Safranek-Shrader, John Scalo, Paul Shapiro
Formation of the first stars and quasars; high-redshift supernovae and metal enrichment; supermassive black hole formation; gamma-ray bursts; reionization of the intergalactic medium; present-day star formation; computational astrophysics.
First Stars & Galaxies, Structure Formation, Theoretical & Computational Astrophysics
Star formation; interstellar medium; turbulence; galaxy evolution; complex systems; astrobiology.
Astrobiology, Milky Way Evolution, Planet Formation, Atmospheres & Life, Star Formation & Protoplanetary Disks
Theoretical astrophysics: cosmology, galaxy formation, the interstellar medium, the intergalactic medium, interstellar dust grains, astrophysical hydrodynamics.
Structure Formation, Milky Way Evolution, Early Universe, First Stars & Galaxies, Cosmic Reionization, Clusters of Galaxies
Star Formation in the First Galaxies; Chemical and Radiative Feedback
from the First Stars and Galaxies; Near-field Cosmology
First Stars & Galaxies, Theoretical & Computational Astrophysics
Observed vs. "accreted" Fe (panel A) and Mg (panel
B) abundances for the sample of metal-poor stars (red circles).
The case where all stars pass through a dense cloud once is also
presented (green open circles). The three most Fe-poor stars are
indicated (crossed circles, diamond). For HE 1327−2326, both
the 1D non-LTE and 3D LTE Fe values are shown. All stars have
accreted fewer metals than what is observed, thus demonstrating
the validity of the basic assumption underlying stellar archaeology.
The minimum Fe and Mg abundance ranges, calculated
under the assumption of a top-heavy Pop III IMF, are given (yellow
region). The approximate Mg abundance arising from a PISN
event in an atomic cooling halo is indicated (dashed line, panel
B), as well as the Fe and Mg levels of enrichment from a 25M⊙
mixing and fallback SN (dotted lines, blue regions). We highlight
those stars (gray regions) that can be used to place constraints on
the Pop III IMF, where accretion does not affect whether they lie
above or below the theoretical "bedrock abundances", predicted
for a top-heavy IMF. Since all observed Mg abundances within
the IMF-sensitive (gray) region to date fall above this bedrock
range, we conclude that a top-heavy IMF is favored for the first
The minimum stellar metallicity observable in the Galaxy