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Titolo:
Zinc as a tracer of metallicity evolution of damped Ly alpha systems
Autore:
Vladilo, G; Bonifacio, P; Centurion, M; Molaro, P;
Indirizzi:
Osservatorio Astron Trieste, I-34131 Trieste, Italy Osservatorio Astron Trieste Trieste Italy I-34131 I-34131 Trieste, Italy
Titolo Testata:
ASTROPHYSICAL JOURNAL
fascicolo: 1, volume: 543, anno: 2000,
parte:, 1
pagine: 24 - 27
SICI:
0004-637X(20001101)543:1<24:ZAATOM>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
METAL ABUNDANCES; ELEMENTAL ABUNDANCES; CHEMICAL ENRICHMENT; CR-II; ZN-II; GALAXIES; DUST; KINEMATICS; ABSORBERS; STARS;
Keywords:
cosmology : observations; galaxies : abundances; galaxies : evolution; quasars : absorption lines;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
30
Recensione:
Indirizzi per estratti:
Indirizzo: Vladilo, G Osservatorio Astron Trieste, Via GB Tiepolo 11, I-34131 Trieste, Italy Osservatorio Astron Trieste Via GB Tiepolo 11 Trieste Italy I-34131
Citazione:
G. Vladilo et al., "Zinc as a tracer of metallicity evolution of damped Ly alpha systems", ASTROPHYS J, 543(1), 2000, pp. 24-27

Abstract

Zinc is a good indicator of metallicity in damped Ly alpha (DLA) systems because it is almost unaffected by dust depletion. However, the use of zinc as a tracer of metallicity evolution has been hampered by the difficulty ofdetecting the Zn II resonance lines at high redshift. The measurement of zinc abundance in a DLA system at z(abs) > 3 obtained by means of the UVES spectrograph at the VLT prompted us to reanalyze the full sample of zinc abundances present in the literature to search for a metallicity-redshift relation in DLA systems. A study of the metallicities of individual systems shows evidence for an anticorrelation between [Zn/H] and redshift, supported by different types of statistical tools. The zinc metallicity decreases by -0.3 +/- 0.1 dex per unit redshift interval in the range 0.5 less than or similar to z(abs) less than or similar to 3.5. This rate is in good agreementwith that found by Savaglio, Panagia, & Stiavelli in their recent study ofDLA abundances corrected for dust depletion. The present result does not require a knowledge of the dust depletion pattern(s) in DLA systems. On the other hand, analysis of the column-density-weighted metallicity of the sample, [Z], does not show a clear evidence for redshift evolution, consistent with previous studies of zinc abundances. We propose that the apparent lackof evolution of [Z] is due to the combination of selection bias effects together with the extreme sensitivity of [Z] to low-number statistics.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 14:04:50