Detection of Pristine Gas Two Billion Years After the Big Bang

  title={Detection of Pristine Gas Two Billion Years After the Big Bang},
  author={Michele Fumagalli and John M. O’Meara and Jason Xavier Prochaska},
  pages={1245 - 1249}
Two cosmic clouds have been observed with a composition close to that of the universe before the first stars were formed. In the current cosmological model, only the three lightest elements were created in the first few minutes after the Big Bang; all other elements were produced later in stars. To date, however, heavy elements have been observed in all astrophysical environments. We report the detection of two gas clouds with no discernible elements heavier than hydrogen. These systems exhibit… 
The Pristine Universe
Two gaseous regions that consist of virtually pristine gas at an epoch where none of the elements heavier than helium are expected to exist are reported, demonstrating the nonuniform dispersion of elements throughout the universe.
Extremely metal-poor gas at a redshift of 7
Observations of hydrogen and heavy-element absorption in a spectrum of a quasar at z =  7.04 imply that the Universe was neither ionized by starlight nor chemically enriched in this neighbourhood at z, and the inferred abundance is too low to promote efficient cooling.
Measurement of the primordial helium abundance from the intergalactic medium
Almost every helium atom in the Universe was created just a few minutes after the Big Bang through a process commonly referred to as Big Bang nucleosynthesis1,2. The amount of helium that was made
The Dawn of Chemistry
Within the precise cosmological framework provided by the Λ-cold dark matter model and standard Big Bang nucleosynthesis, the chemical evolution of the pregalactic gas can now be followed with
Evolution of dispersion in the cosmic deuterium abundance
Deuterium is created during big bang nucleosynthesis, and, in contrast to the other light stable nuclei, can only be destroyed thereafter by fusion in stellar interiors. In this Letter, we study the
Near-Field Cosmology with Extremely Metal-Poor Stars
The oldest, most metal-poor stars in the Galactic halo and satellite dwarf galaxies present an opportunity to explore the chemical and physical conditions of the earliest star-forming environments in
The first stars are the key to the formation of primitive galaxies, early cosmological reionization and chemical enrichment, and the origin of supermassive black holes. Unfortunately, in spite of
Formation of the first stars.
  • V. Bromm
  • Physics
    Reports on progress in physics. Physical Society
  • 2013
Predictions for the upcoming James Webb space telescope (JWST), to be launched ~2018, and for 'stellar archaeology', which probes the abundance pattern in the oldest, most-metal poor stars in the authors' cosmic neighborhood, thereby constraining the nucleosynthesis inside the first supernovae are discussed.
Carbon-enhanced Metal-poor Stars: Relics from the Dark Ages
We use detailed nucleosynthesis calculations and a realistic prescription for the environment of the first stars to explore the first episodes of chemical enrichment that occurred during the dark
On the Formation of the First Quasars
Abstract Observations of the most luminous quasars at redshift z > 6 reveal the existence of numerous supermasssive black holes (>199 M⊙) already in place about 12 billion years ago. In addition, the


An extremely primitive star in the Galactic halo
It is shown that low-mass stars can be formed at very low metallicity, that is, below the critical value of Z, which implies that the stellar material must have experienced temperatures above two million kelvin in its history, given that this is necessary to destroy lithium.
The Era of Massive Population III Stars: Cosmological Implications and Self-Termination
The birth and death of the first generation of stars have important implications for the thermal state and chemical properties of the intergalactic medium (IGM) in the early universe. Sometime after
Three Epochs of Star Formation in the High-Redshift Universe
We investigate the impact of an early population of massive stars on their surroundings. Dissociation of molecular hydrogen by strong UV emission from such stars is expected to produce a global
The Birth of a Galaxy: Primordial Metal Enrichment and Stellar Populations
By definition, Population III stars are metal-free, and their protostellar collapse is driven by molecular hydrogen cooling in the gas phase, leading to large characteristic masses. Population II
Resolving the Formation of Protogalaxies. III. Feedback from the First Stars
The first stars form in dark matter halos of masses ~106 -->M? as suggested by an increasing number of numerical simulations. Radiation feedback from these stars expels most of the gas from the
Cold streams in early massive hot haloes as the main mode of galaxy formation
‘stream-fed galaxies’ are reported, formed from steady, narrow, cold gas streams that penetrate the shock-heated media of massive dark matter haloes and keep the rotating disk configuration intact, although turbulent and broken into giant star-forming clumps that merge into a central spheroid.
Mixing metals in the early Universe
ABSTRA C T We investigate the evolution of the metallicity of the intergalactic medium (IGM) with particular emphasis on its spatial distribution. We propose that metal enrichment occurs as a
The Detectability of Pair-Production Supernovae at z 6
Nonrotating, zero-metallicity stars with initial masses 140 M 260 M☉ are expected to end their lives as pair-production supernovae (PPSNe), in which an electron-positron pair-production instability
First Stars, Very Massive Black Holes, and Metals
Recent studies suggest that the initial mass function (IMF) of the first stars (Population III) is likely to have been extremely top-heavy, unlike what is observed at present. We propose a scenario
The C/O ratio at low metallicity: constraints on early chemical evolution from observations of Galactic halo stars
Aims. We present new measurements of the abundances of carbon and oxygen derived from high-excitation C i and O i absorption lines in metal-poor halo stars, with the aim of clarifying the main