The most metal-poor damped Ly alpha system at z<3: constraints on early nucleosynthesis

Abstract

To constrain the conditions for very early nucleosynthesis in the Universe we compare the chemical enrichment pattern of an extremely metal-poor damped Lyman alpha (DLA) absorber with predictions from recent explosive nucleosynthesis model calculations. For this, we have analyzed chemical abundances in the DLA system at z_abs=2.6183 toward the quasar Q0913+072 (z_em=2.785) using public UVES/VLT high spectral resolution data. The total neutral hydrogen column density in this absorber is logN(HI)=20.36. Accurate column densities are derived for CII, NI, OI, AlII, SiII, and FeII. Upper limits are given for FeIII and NiII. With [C/H]=-2.83, [N/H]=-3.84, and [O/H]=-2.47, this system represents one of the most metal-poor DLA systems investigated so far. It offers the unique opportunity to measure accurate CNO abundances in a protogalactic structure at high redshift. Given the very low overall abundance level and the observed abundance pattern, the data suggest that the chemical evolution of this DLA system is dominated by one or at most a few stellar generations. With reference to numerical model calculations, the chemical abundances in the DLA system are consistent with an enrichment from a single starburst of a zero-metallicity population of massive stars (10-50 M_sun) exploding as core-collapse Supernovae (SNe), i.e., the classical Type II Supernovae (SNeII), and possibly as hyper-energetic (E>10^51erg) core-collapse Supernovae, so-called Hypernovae (HNe), as well. In contrast, models using non-zero metallicity progenitors or other explosion mechanisms, such as pair-instability Supernovae (PISNe) or Type Ia Supernovae (SNeIa), do not match the observed abundance pattern.

9 pages, 4 figures, accepted for publication in Astronomy and Astrophysics

References in corpus (2)

• Nucleosynthetic signatures of the first stars
• First stars VI - Abundances of C, N, O, Li, and mixing in extremely metal-poor giants. Galactic evolution of the light elements

Cited by in corpus (19)

• Deuterium Abundance in the Most Metal-Poor Damped Lyman alpha System: Converging on Omega_baryons
• C, N, O Abundances in the Most Metal-Poor Damped Lyman alpha Systems
• Ultrafaint Dwarf Galaxies - the lowest mass relics from before reionization
• A Homogeneous Sample of Sub-DLAs IV: Global Metallicity Evolution
• The Nitrogen and Oxygen abundances in the neutral gas at high redshift
• The non-LTE line formation of neutral carbon in late-type stars
• Spectral shape of the UV ionizing background and HeII absorption at redshifts 1.8 < z < 2.9
• An integral field spectroscopic survey for high redshift damped Lyman-alpha galaxies
• Boosting Lya and HeII 1640A Line Fluxes from Pop III Galaxies: Stochastic IMF Sampling and Departures from Case-B
• Where are the Cosmic Metals at z~3?
• The nature of NV absorbers at high redshift
• PopIII signatures in the spectra of PopII/I GRBs
• Oxygen-enhanced extremely metal-poor DLAs: A signpost of the first stars?
• The stochastic enrichment of Population II stars
• A Metal-Free Galaxy at $z=3.19$? Evidence of Late Population III Star Formation at Cosmic Noon
• Towards ultra metal-poor DLAs: linking the chemistry of the most metal-poor DLA to the first stars
• VLT/UVES observations of peculiar alpha abundances in a sub-DLA at z ~ 1.8 towards the quasar B1101-26
• A survey of extremely metal-poor gas at cosmic noon: evidence of elevated [O/Fe]
• KBSS-InCLOSE I: Design and First Results from the Inner CGM of QSO Line Of Sight Emitting Galaxies at z~2-3