Evidence of Pop III stars’ chemical signature in neutral gas at z ∼ 6 - A study based on the E-XQR-30 spectroscopic sample

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Table 2.

Weighted average of the chemical abundances of the VMP-DLAs at 2 ≤ z ≤ 4.5 and DLA-analogs at 4.5 < z ≤ 6.5.

z	N	Mean	σ_sample	σ_mean
[C/Si]

2 ≤ z ≤ 4.5	11	−0.21	0.08	0.02
4.5 < z ≤ 6.5	40	−0.19	0.12	0.02

[C/O]

2 ≤ z ≤ 4.5	11	−0.38	0.12	0.04
4.5 < z ≤ 6.5	34	−0.11	0.24	0.04

[C/Fe]

2 ≤ z ≤ 4.5	9	0.14	0.08	0.03
4.5 < z ≤ 6.5	37	0.22	0.14	0.02

[O/Fe]

2 ≤ z ≤ 4.5	20	0.42	0.05	0.01
4.5 < z ≤ 6.5	36	0.32	0.21	0.04

[Si/Fe]

2 ≤ z ≤ 4.5	20	0.32	0.04	0.01
4.5 < z ≤ 6.5	36	0.46	0.13	0.02

[Si/O]

2 ≤ z ≤ 4.5	22	−0.11	0.08	0.02
4.5 < z ≤ 6.5	39	0.11	0.25	0.04

Notes.

The columns report: the redshift interval, the number of systems, the weighted average, the standard deviation of the sample and the standard deviation of the mean.

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