| タイトル | Unveiling the Secrets of Metallicity and Massive Star Formation Using DLAs Along Gamma-Ray Bursts |
| 本文（外部サイト） | http://hdl.handle.net/2060/20150004147 |
| 著者（英） | Cooke, R. J.; Prochaska, J. X.; Cucchiara, A.; Rafelski, M.; Becker, G. D.; Kocevski, D.; Fumagalli, M. |
| 著者所属（英） | NASA Goddard Space Flight Center |
| 発行日 | 2015-04-30 |
| 言語 | eng |
| 内容記述 | We present the largest, publicly available, sample of Damped Lyman-alpha systems (DLAs) along Swift discovered Gamma-ray Bursts (GRB) line of sights in order to investigate the environmental properties of long GRB hosts in the z = 1.8 6 redshift range. Compared with the most recent quasar DLAs sample (QSO-DLA), our analysis shows that GRB-DLAs probe a more metal enriched environment at z approximately greater than 3, up to [X/H] approximately 0.5. In the z = 2 3 redshift range, despite the large number of lower limits, there are hints that the two populations may be more similar (only at 90% significance level) than at higher redshifts. Also, at high-z, the GRB-DLA average metallicity seems to decline at a shallower rate than the QSO-DLAs: GRB-DLA hosts may be polluted with metals at least as far as approximately 2 kpc from the GRB explosion site, probably due to previous star-formation episodes and/or supernovae explosions. This shallow metallicity trend, extended now up to z approximately 5, confirms previous results that GRB hosts are star-forming and have, on average, higher metallicity than the general QSO-DLA population. Finally, our host metallicity measurements are broadly consistent with the predictions derived from the hypothesis of two channels of GRB progenitors, one of which is mildly affected by a metallicity bias, although more data are needed to constrain the models at z approximately greater than 4. |
| NASA分類 | Astrophysics |
| レポートNO | GSFC-E-DAA-TN21332 |
| 権利 | Copyright, Distribution under U.S. Government purpose rights |
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