Discovering extremely compact and metal-poor, star-forming dwarf galaxies out to z ~ 0.9 in the VIMOS Ultra-Deep Survey

Abstract

We report the discovery of 31 low-luminosity (-14.5 > M_{AB}(B) > -18.8), extreme emission line galaxies (EELGs) at 0.2 < z < 0.9 identified by their unusually high rest-frame equivalent widths (100 < EW[OIII] < 1700 A) as part of the VIMOS Ultra Deep Survey (VUDS). VIMOS optical spectra of unprecedented sensitivity ($I_{AB}$ ~ 25 mag) along with multiwavelength photometry and HST imaging are used to investigate spectrophotometric properties of this unique sample and explore, for the first time, the very low stellar mass end (M* < 10^8 M${}_{\odot }$) of the luminosity-metallicity (LZR) and mass-metallicity (MZR) relations at z < 1. Characterized by their extreme compactness (R50 < 1 kpc), low stellar mass and enhanced specific star formation rates (SFR/M* ~ 10^{-9} - 10^{-7} yr^{-1}), the VUDS EELGs are blue dwarf galaxies likely experiencing the first stages of a vigorous galaxy-wide starburst. Using T_e-sensitive direct and strong-line methods, we find that VUDS EELGs are low-metallicity (7.5 < 12+log(O/H) < 8.3) galaxies with high ionization conditions, including at least three EELGs showing HeII 4686A emission and four EELGs of extremely metal-poor (<10% solar) galaxies. The LZR and MZR followed by EELGs show relatively large scatter, being broadly consistent with the extrapolation toward low luminosity and mass from previous studies at similar redshift. However, we find evidences that galaxies with younger and more vigorous star formation -- as characterized by their larger EWs, ionization and sSFR -- tend to be more metal-poor at a given stellar mass.

Letter in A&A 568, L8 (2014). This replacement matches the published version

References in corpus (9)

• The stellar mass assembly of galaxies from z=0 to z=4. Analysis of a sample selected in the rest-frame near-infrared with Spitzer
• The Nature of Extreme Emission Line Galaxies at z=1-2: Kinematics and Metallicities from Near-Infrared Spectroscopy
• Precision abundance analysis of bright HII galaxies
• Extremely metal-poor star-forming galaxies. New detections and general morphological and photometric properties
• AEGIS: Demographics of X-ray and Optically Selected AGNs
• Physical properties of galaxies and their evolution in the VIMOS VLT Deep Survey. I. The evolution of the mass-metallicity relation up to z~0.9
• Constraints on the star-formation rate of z~3 LBGs with measured metallicity in the CANDELS GOODS-South field
• SDSS 0809+1729: Connections Between Extremely Metal Poor Galaxies and Gamma Ray Burst Hosts
• Evidence of very low metallicity and high ionization state in a strongly lensed, star-forming dwarf galaxy at z=3.417

Cited by in corpus (19)

• The VIMOS Ultra-Deep Survey: ~10,000 galaxies with spectroscopic redshifts to study galaxy assembly at early epochs 2<z<~6
• Spectroscopy of superluminous supernova host galaxies. A preference of hydrogen-poor events for extreme emission line galaxies
• VIMOS Ultra-Deep Survey (VUDS): Witnessing the Assembly of a Massive Cluster at z~3.3
• An extremely young massive clump forming by gravitational collapse in a primordial galaxy
• Extreme Emission-Line Galaxies in SDSS. I. Empirical and model-based calibrations of chemical abundances
• Lyman-alpha spectroscopy of extreme [OIII] emitting galaxies at $z\simeq 2-3$: Implications for Ly$\alpha$ visibility and LyC leakage at $z>6$
• Metal-poor, Strongly Star-Forming Galaxies in the DEEP2 Survey: The Relationship between Stellar Mass, Temperature-based Metallicity, and Star Formation Rate
• Chemodynamics of Green Pea galaxies -- I. Outflows and turbulence driving the escape of ionising photons and chemical enrichment
• Ionized gas kinematics and chemical abundances of low-mass star-forming galaxies at $z\sim 3$
• RELICS: Properties of z>5.5 Galaxies Inferred from Spitzer and Hubble Imaging Including A Candidate z~6.8 Strong [OIII] Emitter
• Physical properties of extreme emission-line galaxies at $z\sim 4-9$ from the JWST CEERS survey
• Spatially-resolved chemodynamics of the starburst dwarf galaxy CGCG 007-025: Evidence for recent accretion of metal-poor gas
• Properties of the Lowest Metallicity Galaxies Over the Redshift Range z = 0.2 to z = 1
• A puzzle solved after two decades: SN 2002gh among the brightest of superluminous supernovae
• Chemical Abundances of a Sample of Oxygen-dominated Galaxies
• Recent stellar mass assembly of low-mass star-forming galaxies at redshifts 0.3 < z < 0.9
• Exploring GRBs and supernovae connection: does a superluminous hypernova population exist?
• The Stellar Population of Metal-Poor Galaxies at z $\approx$ 0.8 and the Evolution of the Mass-Metallicity Relation
• J-PAS: First Identification, Physical Properties and Ionization Efficiency of Extreme Emission Line Galaxies