The explosion energy of early stellar populations: the Fe-peak element ratios in low-metallicity damped Lyα systems
نویسندگان
چکیده
The relative abundances of the Fe-peak elements (Ti–Zn) at the lowest metallicities are intimately linked to the physics of core-collapse supernova explosions. With a sample of 25 very metal poor damped Lyα systems (DLAs), we investigate the trends of the Fe-peak element ratios with metallicity. For nine of the 25 DLAs, a direct measurement (or useful upper limit) of one or more of the Ti, Cr, Co, Ni, Zn/Fe abundance ratios could be determined from detected absorption lines. For the remaining systems (without detections), we devised a new form of spectral stacking to estimate the typical Fe-peak element ratios of the DLA population in this metallicity regime. We compare these data to analogous measurements in metal-poor stars of the Galactic halo and to detailed calculations of explosive nucleosynthesis in metal-free stars. We conclude that most of the DLAs in our sample were enriched by stars that released an energy of 1.2 × 1051 erg when they exploded as core-collapse supernovae. Finally, we discuss the exciting prospect of measuring Fe-peak element ratios in DLAs with Fe/H < 1/1000 of solar when 30-m class telescopes become available. Only then will we be able to pin down the energy that was released by the supernovae of the first stars.
منابع مشابه
THE UCSD HIRES/KECKI DAMPED Lyα ABUNDANCE DATABASE II. THE IMPLICATIONS
We present a comprehensive analysis of the damped Lyα abundance database presented in the first paper of this series. This database provides a homogeneous set of abundance measurements for many elements including Si, Cr, Ni, Zn, Fe, Al, S, Co, O, and Ar from 38 damped Lyα systems with zabs > 1.5. With little exception, these damped Lyα systems exhibit very similar relative abundances. There is ...
متن کاملStellar Populations in the Central Galaxies of Fossil Groups
It is inferred from the symmetrical and luminous X-ray emission of fossil groups that they are mature, relaxed galaxy systems. Cosmological simulations and observations focusing on their dark halo and inter-galactic medium properties confirm their early formation. Recent photometric observations suggest that, unlike the majority of non-fossil brightest group galaxies (BGGs), the central early-t...
متن کاملPROBING HIGH-REDSHIFT DISKS WITH DAMPED Lyα SYSTEMS
Evidence is presented that the damped Lyα absorption systems are the high-redshift (z > 3) progenitors of galaxy disks. I discuss kinematic evidence that the damped Lyα systems are rotating disks. I also discuss implications of the lack of metal-poor damped Lyα systems with line width ∆v > 100 km s. I then present new evidence stemming from correlations between element-abundance ratios and [Fe/...
متن کاملON THE EVOLUTION OF DAMPED Lyα SYSTEMS TO GALACTIC DISKS
The mean metallicity of the thick disk of the Galaxy is 0.5 dex higher than that of the damped Lyα systems. This has been interpreted to argue that stars in the former do not arise out of gas in the latter. Using new metallicity and H I column-density data we show the metal-rich damped systems do contain sufficient baryons at the thick-disk metallicity to account for the stellar masses of thick...
متن کاملCHEMICAL ABUNDANCES OF THE DAMPED Ly α SYSTEMS AT
We present chemical abundance measurements for 19 damped Lyα systems observed with HIRES on the 10m W.M. Keck Telescope. We perform a detailed analysis of every system, deriving ionic column densities for all unblended metal-line transitions. Our principal goal is to investigate the abundance patterns of the damped systems and thereby determine the underlying physical processes which dominate t...
متن کامل