Table 2.
Adopted and derived parameters of the major merger model and observational constraints.
| Adopted and derived parameters of the model at z = 1 | ||
|---|---|---|
| Parameter | Main | Secondary |
| (12+log(O/H))R = 0 [dex] | 9.0 | 8.75 |
| ∇(12+log(O/H)) [dex/kpc] | −0.1 | −0.1 |
| ⟨12+log(O/H)⟩Stellar, < 1Re [dex] | 8.73 | 8.48 |
| ⟨12+log(O/H)⟩Gas, < 1Re [dex] | 8.70 | 8.45 |
| Derived parameters of the model at z = 0 | ||
| Parameter | Old stars | Young stars |
| ⟨12+log(O/H)⟩ [dex] | 8.47 | 8.67 |
| σ (12+log(O/H)) [dex] | 0.35 | 0.36 |
| (12+log(O/H))R = 0 [dex] | 8.52 | 8.77 |
| ∇(12+log(O/H)) [dex/Rd] | −0.06 | −0.075 |
| PNe survey (Bhattacharya et al. 2022) | ||
| Parameter | Old PNe | Young PNe |
| ⟨12+log(O/H)⟩ [dex] | 8.48 ± 0.02 | 8.57 ± 0.03 |
| ⟨12+log(Ar/H)⟩ [dex] | 6.25 ± 0.02 | 6.32 ± 0.03 |
| σ (12+log(O/H)) [dex] | 0.21 | 0.28 |
| σ (12+log(Ar/H)) [dex] | 0.20 | 0.29 |
| (12+log(O/H))R = 0 [dex] | 8.31 ± 0.05 | 8.6 ± 0.08 |
| (12+log(Ar/H))R = 0 [dex] | 6.3 ± 0.05 | 6.51 ± 0.08 |
| ∇(12+log(O/H)) [dex/rd] | 0.036 ± 0.018 | −0.079 ± 0.036 |
| ∇(12+log(Ar/H)) [dex/rd] | −0.03 ± 0.018 | −0.109 ± 0.036 |
| RGB survey (Gregersen et al. 2015) | ||
| Parameter | 4 Gyr old RGBs | |
| ∇[M/H] [dex/kpc] | −0.02 ± 0.004 | |
Notes. (12+log(O/H))R = 0 and ∇ (12+log(O/H)) are the adopted values for the linear functional form (Eq. (2)) of the oxygen abundance in the initial discs, that is the central value of the oxygen abundance and its gradient along the galactocentric radius. ⟨12+log(O/H)⟩Stellar, < 1Re and ⟨12+log(O/H)⟩Gas, < 1Re are the oxygen abundance values we compute within one Re for the initial discs at z = 1. The derived parameters for the remnant disc at z = 0 are the average oxygen abundance (⟨12+log(O/H)⟩) for the two families of modelled stars, older and younger than 3.5 Gyr and its standard deviation (σ), their central abundance ((12+log(O/H))R = 0), and the oxygen abundance gradient (∇(12+log(O/H))). The same parameters for oxygen and argon abundances are reported for the two families (old: > 4.5 Gyr; young: ∼2.5 Gyr) of PNe from Bhattacharya et al. (2022). The metallicity gradient reported in Gregersen et al. (2015) is also noted.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.