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.

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

References in corpus (44)

• Stellar population synthesis at the resolution of 2003
• Galactic Stellar and Substellar Initial Mass Function
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• The Global Schmidt Law in Star Forming Galaxies
• New Insight on Galaxy Formation and Evolution from Keck Spectroscopy of the Hawaii Deep Fields
• A fundamental relation between mass, SFR and metallicity in local and high redshift galaxies
• AMAZE. I. The evolution of the mass-metallicity relation at z>3
• The Star-formation Mass Sequence out to z=2.5
• 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
• Galaxy Zoo Green Peas: Discovery of A Class of Compact Extremely Star-Forming Galaxies
• The Mass-Metallicity Relation with the Direct Method on Stacked Spectra of SDSS Galaxies
• Ionization State of Inter-Stellar Medium in Galaxies: Evolution, SFR-M_star-Z Dependence, and Ionizing Photon Escape
• The impact of the nitrogen-to-oxygen ratio on ionized nebulae diagnostics based on [NII] emission lines
• Dust extinction from Balmer decrements of star-forming galaxies at 0.75<z<1.5 with HST/WFC3 spectroscopy from the WISP survey
• Metallicity evolution, metallicity gradients and gas fractions at z~3.4
• The Origin and Optical Depth of Ionizing Radiation in the "Green Pea" Galaxies
• The Mass-Metallicity and Luminosity-Metallicity Relation from DEEP2 at z ~ 0.8
• A New Diagnostic of Active Galactic Nuclei: Revealing Highly-Absorbed Systems at Redshift>0.3
• Very Strong Emission-Line Galaxies in the WISP Survey and Implications for High-Redshift Galaxies
• On the oxygen and nitrogen chemical abundances and the evolution of the "green pea" galaxies
• The metallicity of the long GRB hosts and the Fundamental Metallicity Relation of low-mass galaxies
• Strong Emission Line HII Galaxies in the Sloan Digital Sky Survey. I. Catalog of DR1 Objects with Oxygen Abundances from Te easurements
• The zCOSMOS Redshift Survey: the role of environment and stellar mass in shaping the rise of the morphology-density relation from z~1
• Extreme Emission Line Galaxies in CANDELS: Broad-Band Selected, Star-Bursting Dwarf Galaxies at z>1
• Line temperatures and elemental abundances in HII galaxies
• The star formation history and metal content of the "Green Peas". New detailed GTC-OSIRIS spectrophotometry of three galaxies
• Massive star formation in a gravitationally-lensed HII-galaxy at z=3.357
• 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
• The cosmic evolution of oxygen and nitrogen abundances in star-forming galaxies over the past 10 Gyrs
• 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
• Systematic search for extremely metal poor galaxies in the Sloan Digital Sky Survey
• Constraints on the star-formation rate of z~3 LBGs with measured metallicity in the CANDELS GOODS-South field
• An investigation of the luminosity-metallicity relation for a large sample of low-metallicity emission-line galaxies
• Metallicity inhomogeneities in local star-forming galaxies as sign of recent metal-poor gas accretion
• "Direct" Gas-phase Metallicities, Stellar Properties, and Local Environments of Emission-line Galaxies at Redshift below 0.90
• The metallicity evolution of low mass galaxies: New constraints at intermediate redshift
• The DEEP2 Galaxy Redshift Survey: Discovery of Luminous, Metal-poor, Sta r-forming Galaxies at Redshifts z~0.7
• SDSS 0809+1729: Connections Between Extremely Metal Poor Galaxies and Gamma Ray Burst Hosts
• Deep Spectroscopy of Ultra-Strong Emission Line Galaxies
• Evidence of very low metallicity and high ionization state in a strongly lensed, star-forming dwarf galaxy at z=3.417
• Spectrophotometric properties of galaxies at intermediate redshifts (z ~ 0.2--1.0) II. The Luminosity -- Metallicity relation

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• Spectroscopy of superluminous supernova host galaxies. A preference of hydrogen-poor events for extreme emission line galaxies
• An extreme [OIII] emitter at $z=3.2$: a low metallicity Lyman continuum source
• Cosmic evolution and metal aversion in super-luminous supernova host galaxies
• Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). II. Discovery of 32 Quasars and Luminous Galaxies at 5.7 < z < 6.8
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• Molecular gas in low-metallicity starburst galaxies: Scaling relations and the CO-to-H${}_2$ conversion factor
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• The Metal Abundances across Cosmic Time ($\mathcal{M}\mathcal{A}\mathcal{C}\mathcal{T}$) Survey. II. Evolution of the Mass-Metallicity Relation over 8 Billion Years, using [OIII]$\lambda$4363Å-based Metallicities
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• Search for Extremely Metal-poor Galaxies in the Sloan Digital Sky Survey (II): high electron temperature objects
• 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 $z>6$
• Stellar Mass--Gas-phase Metallicity Relation at $0.5\le z\le 0.7$: A Power Law with Increasing Scatter toward the Low-mass Regime
• Characterization of star-forming dwarf galaxies at 0.1 $\lesssim z\lesssim$ 0.9 in VUDS: Probing the low-mass end of the mass-metallicity relation
• 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
• Direct T${}_e$ metallicity calibration of R23 in strong line emitters
• Ionized gas kinematics and chemical abundances of low-mass star-forming galaxies at $z\sim 3$
• The Number Density Evolution of Extreme Emission Line Galaxies in 3D-HST: Results from a Novel Automated Line Search Technique for Slitless Spectroscopy
• Local anti-correlation between star-formation rate and gas-phase metallicity in disk galaxies
• RELICS: Spectroscopy of gravitationally-lensed $z\simeq 2$ reionization-era analogs and implications for CIII] detections at $z>6$
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• Mass - metallicity relation and fundamental metallicity relation of metal-poor star-forming galaxies at $0.6<z<0.9$ from the eBOSS survey
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• RELICS: Properties of z>5.5 Galaxies Inferred from Spitzer and Hubble Imaging Including A Candidate z~6.8 Strong [OIII] Emitter
• Starburst galaxies in the COSMOS field: clumpy star-formation at redshift 0 < z < 0.5
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• Chemical Abundances of a Sample of Oxygen-dominated Galaxies
• 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
• 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
• Prospects for extending the Mass-Metallicity Relation to low mass at high redshift: a case study at z~1
• J-PAS: First Identification, Physical Properties and Ionization Efficiency of Extreme Emission Line Galaxies