Differences and similarities of stellar populations in LAEs and LBGs at z ∼ 3.4−6.8
Lyman alpha emitters (LAEs) and Lyman break galaxies (LBGs) represent the most common groups of star-forming galaxies at high z, and the differences between their inherent stellar populations (SPs) are a key factor in understanding early galaxy formation and evolution. We have run a set of SP burst-...
| Autores: | , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/6499 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/6499 |
| Access Level: | acceso abierto |
| Palabra clave: | 52 Ly-alpha-emittes Lyman-break galaxies Star-forming galaxies Luminosity function Mass function Escape fraction Formation rates Number counts Evolution Redshift Astrofísica Astronomía (Física) |
| Sumario: | Lyman alpha emitters (LAEs) and Lyman break galaxies (LBGs) represent the most common groups of star-forming galaxies at high z, and the differences between their inherent stellar populations (SPs) are a key factor in understanding early galaxy formation and evolution. We have run a set of SP burst-like models for a sample of 1558 sources at 3.4 <z< 6.8 from the Survey for High-z Absorption Red and Dead Sources (SHARDS) over the GOODS-N field. This work focuses on the differences between the three different observational subfamilies of our sample: LAE–LBGs, no-Ly α LBGs, and pure LAEs. Single and double SP synthetic spectra were used to model the spectral energy distributions, adopting a Bayesian information criterion to analyze under which situations a second SP is required. We find that the sources are well modelled using a single SP in ∼ 79 per cent of the cases. The best models suggest that pure LAEs are typically young low-mass galaxies (t ∼ 26^(+41)_(−25) Myr; M_(star) ∼ 5.6^(+12.0) _(−5.5) × 10^(8) Mͽ), undergoing one of their first bursts of star formation. On the other hand, no-Ly α LBGs require older SPs (t ∼ 71 ± 12 Myr), and they are substantially more massive (M_(star) ∼ 3.5 ± 1.1 × 10^(9) Mͽ). LAE–LBGs appear as the subgroup that more frequently needs the addition of a second SP, representing an old and massive galaxy caught in a strong recent star-forming episode. The relative number of sources found from each subfamily at each z supports an evolutionary scenario from pure LAEs and single SP LAE–LBGs to more massive LBGs. Stellar mass functions are also derived, finding an increase of M∗ with cosmic time and a possible steepening of the low-mass slope from z ∼ 6 to z ∼ 5 with no significant change to z ∼ 4. Additionally, we have derived the SFR–M_(star) relation, finding an SFR ∝ M^(β)_(star) behaviour with negligible evolution from z ∼ 4 to z ∼ 6. |
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