Recent stellar mass assembly of low-mass star-forming galaxies at redshifts 0.3 < z < 0.9*
The epoch when low-mass star-forming galaxies (LMSFGs) form the bulk of their stellar mass is uncertain. While some models predict an early formation, others favor a delayed scenario until later ages of the universe. We present constraints on the star formation histories (SFHs) of a sample of LMSFGs...
| Autores: | , , , , , , , |
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| Formato: | artículo |
| Fecha de publicación: | 2015 |
| País: | España |
| Recursos: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/33891 |
| Acesso em linha: | https://hdl.handle.net/20.500.14352/33891 |
| Access Level: | acceso abierto |
| Palavra-chave: | 52 Extragalactic legacy survey Compact dwarf galaxies Digital sky survey To-fir analysis Space-telescope Photometric redshifts Spitzer/Irac sources Formation histories Advanced camera Data-reduction Astrofísica |
| Resumo: | The epoch when low-mass star-forming galaxies (LMSFGs) form the bulk of their stellar mass is uncertain. While some models predict an early formation, others favor a delayed scenario until later ages of the universe. We present constraints on the star formation histories (SFHs) of a sample of LMSFGs obtained through the analysis of their spectral energy distributions using a novel approach that (1) consistently combines photometric (broadband) and spectroscopic (equivalent widths of emission lines) data, and (2) uses physically motivated SFHs with non-uniform variations of the star formation rate (SFR) as a function of time. The sample includes 31 spectroscopically confirmed LMSFGs (7.3 <= logM(*)/M circle dot <= 8.0), at 0.3 < z(spec) < 0.9, in the Extended-Chandra Deep Field-South field. Among them, 24 were selected with photometric stellarmass logM(*)/M circle dot < 8.0, 0.3< z(phot) < 1.0, and m(NB816, AB) < 26 mag; the remaining 7 were selected as blue compact dwarfs within the same photometric redshift and magnitude ranges. We also study a secondary sample of 43 more massive spectroscopically confirmed galaxies (8.0 < logM(*)/M circle dot <= 9.1), selected with the same criteria. The SFRs and stellar masses derived for both samples place our targets on the standard main sequence of star-forming galaxies. The median SFH of LMSFGs at intermediate redshifts appears to form 90% of the median stellar mass inferred for the sample in the similar to 0.5-1.8 Gyr immediately preceding the observation. These results suggest a recent stellar mass assembly for LMSFGs, consistent with the cosmological downsizing trends. We find similar median SFH timescales for the more massive secondary sample. |
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