Bibcode
Lumbreras-Calle, A.; Muñoz-Tuñón, C.; Méndez-Abreu, J.; Mas-Hesse, J. M.; Pérez-González, P. G.; Alcalde Pampliega, B.; Arrabal Haro, P.; Cava, A.; Domínguez Sánchez, H.; Eliche-Moral, M. C.; Alonso-Herrero, A.; Borlaff, A.; Gallego, J.; Hernán-Caballero, A.; Koekemoer, A. M.; Rodríguez-Muñoz, L.
Bibliographical reference
Astronomy and Astrophysics, Volume 621, id.A52, 16 pp.
Advertised on:
1
2019
Journal
Citations
13
Refereed citations
12
Description
Context. The physical processes driving the evolution of star formation
(SF) in galaxies over cosmic time still present many open questions.
Recent galaxy surveys allow now to study these processes in great detail
at intermediate redshift (0 ≤ z ≤ 0.5). Aims: We build a
complete sample of star-forming galaxies and analyze their properties,
reaching systems with low stellar masses and low star formation rates
(SFRs) at intermediate-to-low redshift. Methods: We use data from
the SHARDS multiband survey in the GOODS-North field. Its depth (up to
magnitude ⟨m3σ⟩ 26.5) and its
spectro-photometric resolution (R 50) provides us with an ideal
dataset to search for emission line galaxies (ELGs). We develop a new
algorithm to identify low-redshift (z < 0.36) ELGs by detecting the
[OIII]5007 and Hα emission lines simultaneously. We fit the
spectral energy distribution (SED) of the selected sample, using a model
with two single stellar populations. Results: We find 160
star-forming galaxies for which we derive equivalent widths (EWs) and
absolute fluxes of both emission lines. We detect EWs as low as 12
Å, with median values for the sample of 35 Å in [OIII]5007
and 56 Å in Hα, respectively. Results from the SED fitting
show a young stellar population with low median metallicity (36% of the
solar value) and extinction (AV 0.37), with median galaxy
stellar mass 108.5 M⊙. Gas-phase
metallicities measured from available spectra are also low. ELGs in our
sample present bluer colours in the UVJ plane than the median
colour-selected star-forming galaxy in SHARDS. We suggest a new V-J
colour criterion to separate ELGs from non-ELGs in blue galaxy samples.
In addition, several galaxies present high densities of O-type stars,
possibly producing galactic superwinds, which makes them interesting
targets for follow-up spectroscopy. Conclusions: We have
demonstrated the efficiency of SHARDS in detecting low-mass ELGs ( 2
magnitudes deeper than previous spectroscopic surveys in the same
field). The selected sample accounts for 20% of the global galaxy
population at this redshift and luminosity, and is characterized by
young SF bursts with sub-solar metallicities and low extinction.
However, robust fits to the full SEDs can only be obtained including an
old stellar population, suggesting the young component is built up by a
recent burst of SF in an otherwise old galaxy.
Full Tables 1 and 2 are only available at the CDS via anonymous ftp to
http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/621/A52
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