We present precise abundance determinations of two near-pristine damped Lyα systems (DLAs) to assess the nature of the [O/Fe] ratio at [Fe/H] < -3.0 (i.e., <1/1000 of the solar metallicity). Prior observations indicate that the [O/Fe] ratio is consistent with a constant value, [O/Fe] ≃ +0.4, when -3 < [Fe/H] < -2, but this ratio may increase when [Fe/H] ≲ -3. In this paper, we test this picture by reporting new, high-precision [O/Fe] abundances in two of the most metal-poor DLAs currently known. We derive values of [O/Fe] = +0.50 ± 0.10 and [O/Fe] = +0.62 ± 0.05 for these two z ≃ 3 near-pristine gas clouds. These results strengthen the idea that the [O/Fe] abundances of the most metal-poor DLAs are elevated compared to DLAs with [Fe/H] ≳ -3. We compare the observed abundance pattern of the latter system to the nucleosynthetic yields of Population III supernovae (SNe), and find that the enrichment can be described by a (19-25) M⊙ Population III SN that underwent a (0.9-2.4) × 1051 erg explosion. These high-precision measurements showcase the behavior of [O/Fe] in the most metal-poor environments. Future high-precision measurements in new systems will contribute to a firm detection of the relationship between [O/Fe] and [Fe/H]. These data will reveal whether we are witnessing a chemical signature of enrichment from Population III stars and allow us to rule out contamination from Population II stars.

Welsh, L., Cooke, R., Fumagalli, M., Pettini, M. (2022). Oxygen-enhanced Extremely Metal-poor Damped Ly-alpha Systems: A Signpost of the First Stars?. THE ASTROPHYSICAL JOURNAL, 929(2) [10.3847/1538-4357/ac4503].

Oxygen-enhanced Extremely Metal-poor Damped Ly-alpha Systems: A Signpost of the First Stars?

Louise Welsh
;
Michele Fumagalli;
2022

Abstract

We present precise abundance determinations of two near-pristine damped Lyα systems (DLAs) to assess the nature of the [O/Fe] ratio at [Fe/H] < -3.0 (i.e., <1/1000 of the solar metallicity). Prior observations indicate that the [O/Fe] ratio is consistent with a constant value, [O/Fe] ≃ +0.4, when -3 < [Fe/H] < -2, but this ratio may increase when [Fe/H] ≲ -3. In this paper, we test this picture by reporting new, high-precision [O/Fe] abundances in two of the most metal-poor DLAs currently known. We derive values of [O/Fe] = +0.50 ± 0.10 and [O/Fe] = +0.62 ± 0.05 for these two z ≃ 3 near-pristine gas clouds. These results strengthen the idea that the [O/Fe] abundances of the most metal-poor DLAs are elevated compared to DLAs with [Fe/H] ≳ -3. We compare the observed abundance pattern of the latter system to the nucleosynthetic yields of Population III supernovae (SNe), and find that the enrichment can be described by a (19-25) M⊙ Population III SN that underwent a (0.9-2.4) × 1051 erg explosion. These high-precision measurements showcase the behavior of [O/Fe] in the most metal-poor environments. Future high-precision measurements in new systems will contribute to a firm detection of the relationship between [O/Fe] and [Fe/H]. These data will reveal whether we are witnessing a chemical signature of enrichment from Population III stars and allow us to rule out contamination from Population II stars.
Articolo in rivista - Articolo scientifico
Damped Lyman-alpha systems; Intergalactic medium; Population III stars; Population II stars; Chemical abundances;
English
2022
929
2
158
open
Welsh, L., Cooke, R., Fumagalli, M., Pettini, M. (2022). Oxygen-enhanced Extremely Metal-poor Damped Ly-alpha Systems: A Signpost of the First Stars?. THE ASTROPHYSICAL JOURNAL, 929(2) [10.3847/1538-4357/ac4503].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/397312
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