| Autor: |
Christensen, L., Jakobsen, P., Willott, C., Arribas, S., Bunker, A., Charlot, S., Maiolino, R., Marshall, M., Perna, M., Übler, H. |
| Rok vydání: |
2023 |
| Předmět: |
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| Zdroj: |
A&A 680, A82 (2023) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1051/0004-6361/202347943 |
| Popis: |
We present JWST/NIRSpec R~2700 spectra of four high-redshift quasars: VDES J0020-3653 (z = 6.860), DELS J0411-0907 (z = 6.825), UHS J0439+1634 (z = 6.519) and ULAS J1342+0928 (z = 7.535). The exquisite data quality, signal-to-noise ratio of 50-200, and large $0.86\!~\mu{\rm m}\le \lambda \le 5.5\!~\mu{\rm m}$ spectral coverage allows us to identify between 13 and 17 intervening and proximate metal absorption line systems in each quasar spectrum, with a total number of 61 absorption-line systems detected at 2.426 and find: i) A continued increase of the low-ionization OI, CII, and SiII incidence, ii) Decreasing high-ionization CIV and SiIV incidence with a transition from predominantly high- to low-ionization at $z\approx6.0$, and iii) a constant MgII incidence across all redshifts. The observations support a change in the ionization state of the intergalactic medium in the EoR rather than a change in metallicity. The abundance ratio of [Si/O] in five z>6 absorption systems show enrichment signatures produced by low-mass Pop III pair instability supernovae, and possibly Pop III hypernovae. In the Gunn-Peterson troughs we detect transmission spikes where Ly$\alpha$ photons can escape. From 22 absorption systems at z>5.7, only a single low-ionization system out of 13 lies within 2000 km/s from a spike, while four high-ionization systems out of nine lie within ~2000 km/s from a spike. This confirms that galaxies responsible for the heavy elements that are transported into the circumgalactic medium lie in predominantly in high-density, neutral environments, while lower density environments are ionized without being polluted by metals at $z\approx$ 6-7. [abridged]
Comment: 48 pages including 28 pages of appendices. Accepted for publication in A&A |
| Databáze: |
arXiv |
| Externí odkaz: |
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