HETDEX [OIII] Emitters I: A spectroscopically selected low-redshift population of low-mass, low-metallicity galaxies

Abstract

We assemble a sample of 17 low metallicity (7.45 < log(O/H)+12 < 8.12) galaxies with z < 0.1 found spectroscopically, without photometric pre-selection, in early data from the Hobby Eberly Telescope Dark Energy Experiment (HETDEX). Star forming galaxies that occupy the lowest mass and metallicity end of the mass-metallicity relation tend to be under sampled in continuum-based surveys as their spectra are typically dominated by emission from newly forming stars. We search for galaxies with high [OIII]$\lambda$5007 / [OII]$\lambda$3727, implying highly ionized nebular emission often indicative of low metallicity systems. With the Second Generation Low Resolution Spectrograph on the Hobby Eberly Telescope we acquired follow-up spectra, with higher resolution and broader wavelength coverage, of each low-metallicity candidate in order to confirm the redshift, measure the H$\alpha$ and [NII] line strengths and, in many cases, obtain deeper spectra of the blue lines. We find our galaxies are consistent with the mass-metallicity relation of typical low mass galaxies. However, galaxies in our sample tend to have similar specific star formation rates (sSFRs) as the incredibly rare "blueberry" galaxies found in (Yang et. al. 2017). We illustrate the power of spectroscopic surveys for finding low mass and metallicity galaxies and reveal that we find a sample of galaxies that are a hybrid between the properties of typical dwarf galaxies and the more extreme blueberry galaxies.

arXiv comment32 pages, 12 figures, 8 tables, Accepted for publication in ApJ

References in corpus (69)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The Sloan Digital Sky Survey: Technical Summary
• Galactic Stellar and Substellar Initial Mass Function
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• On the variation of the Initial Mass Function
• Star Formation in Galaxies Along the Hubble Sequence
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• The Seventh Data Release of the Sloan Digital Sky Survey
• The Origin of the Mass--Metallicity Relation: Insights from 53,000 Star-Forming Galaxies in the SDSS
• The physical properties of star forming galaxies in the low redshift universe
• Star Formation in the Milky Way and Nearby Galaxies
• Evolutionary tracks and isochrones for low- and intermediate-mass stars: from 0.15 to 7 M_sun, and from Z=0.0004 to 0.03
• The Galaxy Evolution Explorer: A Space Ultraviolet Survey Mission
• The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• Overview of the DESI Legacy Imaging Surveys
• [O III]/[N II] as an Abundance Indicator at High Redshift
• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• Cosmic-Ray Rejection by Laplacian Edge Detection
• Evolution of asymptotic giant branch stars II. Optical to far-infrared isochrones with improved TP-AGB models
• Metallicity Calibrations and the Mass-Metallicity Relation for Star-Forming Galaxies
• CALIFA, the Calar Alto Legacy Integral Field Area survey: I. Survey presentation
• The propagation of uncertainties in stellar population synthesis modeling III: model calibration, comparison, and evaluation
• Using Strong Lines to Estimate Abundances in Extragalactic HII Regions and Starburst Galaxies
• A fundamental relation between mass, SFR and metallicity in local and high redshift galaxies
• The Evolution of the Stellar Mass Functions of Star-Forming and Quiescent Galaxies to z = 4 from the COSMOS/UltraVISTA Survey
• AMAZE. I. The evolution of the mass-metallicity relation at z>3
• Analysis of galaxy SEDs from far-UV to far-IR with CIGALE: Studying a SINGS test sample
• Modeling the Panchromatic Spectral Energy Distributions of Galaxies
• The Dust Opacity of Star-Forming Galaxies
• 3D-HST: A wide-field grism spectroscopic survey with the Hubble Space Telescope
• De Re Metallica: The cosmic chemical evolution of galaxies
• The chemical composition of metal-poor emission-line galaxies in the Data Release 3 of the Sloan Digital Sky Survey
• Dust-Corrected Star Formation Rates of Galaxies. I. Combinations of H-alpha and Infrared Tracers
• 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
• The SAMI Galaxy Survey: instrument specification and target selection
• The Spitzer Local Volume Legacy: Survey Description and Infrared Photometry
• An H-alpha Imaging Survey of Galaxies in the Local 11 Mpc Volume
• New light on the search for low metallicity galaxies I. The N2 method
• Nebular Continuum and Line Emission in Stellar Population Synthesis Models
• The most metal-poor galaxies
• Gas metallicity diagnostics in star-forming galaxies
• Direct Oxygen Abundances for Low Luminosity LVL Galaxies
• New fully empirical calibrations of strong-line metallicity indicators in star forming galaxies
• Green Pea Galaxies and cohorts: Luminous Compact Emission-Line Galaxies in the Sloan Digital Sky Survey
• On the oxygen and nitrogen chemical abundances and the evolution of the "green pea" galaxies
• HETDEX pilot survey for emission-line galaxies - I. Survey design, performance, and catalog
• "Direct" Gas-Phase Metallicity in Local Analogs of High-Redshift Galaxies: Empirical Metallicity Calibrations for High-Redshift Star-Forming Galaxies
• Blueberry galaxies: the lowest mass young starbursts
• GRAPES, Grism Spectroscopy of the Hubble Ultra Deep Field: Description and Data Reduction
• First Results from the 3D-HST Survey: The Striking Diversity of Massive Galaxies at z>1
• The cosmic evolution of oxygen and nitrogen abundances in star-forming galaxies over the past 10 Gyrs
• The KPNO International Spectroscopic Survey. I. Description of the Survey
• Characterizing Dust Attenuation in Local Star Forming Galaxies: UV and Optical Reddening
• The VIRUS-P Exploration of Nearby Galaxies (VENGA): Survey Design, Data Processing, and Spectral Analysis Methods
• Aperture-free star formation rate of SDSS star-forming galaxies
• The Leoncino Dwarf Galaxy: Exploring the Low-Metallicity End of the Luminosity-Metallicity and Mass-Metallcity Relations
• Deep Spectroscopy of Ultra-Strong Emission Line Galaxies
• MUSE Spectroscopic Identifications of Ultra-Faint Emission Line Galaxies with M${}_{\mathrm{UV}}\sim$ -15
• Properties of the KISS Green Pea Galaxies
• Young, Star-forming Galaxies and their local Counterparts: the Evolving Relationship of Mass-SFR-Metallicity since z ~ 2.1
• Hector - a new massively multiplexed IFS instrument for the Anglo-Australian Telescope
• MCSED: A flexible spectral energy distribution fitting code and its application to $z\sim 2$ emission-line galaxies
• The metallicity evolution of blue compact dwarf galaxies from the intermediate redshift to the local Universe
• HETDEX Pilot Survey. VI. [OIII] Emitters and Expectations for a Local Sample of Star Forming Galaxies in HETDEX

Cited by in corpus (4)

• The HETDEX Instrumentation: Hobby-Eberly Telescope Wide Field Upgrade and VIRUS
• A panchromatic view of star cluster formation in a simulated dwarf galaxy starburst
• Low Metallicity Galaxies from the Dark Energy Survey
• Searching for Supernovae in HETDEX Data Release 3