The M33 Metallicity Project: Resolving the Abundance Gradient Discrepancies in M33

Abstract

We present a new determination of the metallicity gradient in M33, based on Keck/LRIS measurements of oxygen abundances using the temperature-sensitive emission line [OIII] 4363 A in 61 HII regions. These data approximately triple the sample of direct oxygen abundances in M33. We find a central abundance of 12 + log(O/H) = 8.36+/-0.04 and a slope of -0.027+/-0.012 dex/kpc, in agreement with infrared measurements of the neon abundance gradient but much shallower than most previous oxygen gradient measurements. There is substantial intrinsic scatter of 0.11 dex in the metallicity at any given radius in M33, which imposes a fundamental limit on the accuracy of gradient measurements that rely on small samples of objects. We also show that the ionization state of neon does not follow the ionization state of oxygen as is commonly assumed, suggesting that neon abundance measurements from optical emission lines require careful treatment of the ionization corrections.

10 pages, Accepted to ApJ

References in corpus (15)

• Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant
• Linear Regression for Astronomical Data with Measurement Errors and Intrinsic Scatter
• The chemical composition of metal-poor emission-line galaxies in the Data Release 3 of the Sloan Digital Sky Survey
• The Composition Gradient in M101 Revisited. II. Electron Temperatures and Implications for the Nebular Abundance Scale
• A Survey of Local Group Galaxies Currently Forming Stars. I. UBVRI Photometry of Stars in M31 and M33
• The Extended Rotation Curve and the Dark Matter Halo of M33
• Giant Molecular Clouds in M33 -- II. High Resolution Observations
• Synthetic spectra of H Balmer and HeI absorption lines. II: Evolutionary synthesis models for starburst and post-starburst galaxies
• The metallicity gradient of M 33: chemical abundances of HII regions
• Neon and Argon optical emission lines in ionized gaseous nebulae: Implications and applications
• Neon and Oxygen Abundances in M33
• The evolution of emission lines in HII galaxies
• Deep VLT spectroscopy of the blue compact dwarf galaxies Tol 1214-277 and Tol 65
• Determination of the Distance to M33 Based on Single Epoch I-band HST Observations of Cepheids
• Chemical Abundances of Planetary Nebulae in M33

Cited by in corpus (128)

• The CO-to-H2 Conversion Factor From Infrared Dust Emission Across the Local Group
• Optical Spectroscopy and Nebular Oxygen Abundances of the Spitzer/SINGS Galaxies
• The Resolved Properties of Extragalactic Giant Molecular Clouds
• Extragalactic chemical abundances: do HII regions and young stars tell the same story? The case of the spiral galaxy NGC 300
• Low CO Luminosities in Dwarf Galaxies
• The flat oxygen abundance gradient in the extended disk of M83
• HII Region Metallicity Distribution in the Milky Way Disk
• A Comparative Study of Giant Molecular Clouds in M51, M33 and the Large Magellanic Cloud
• Keck HIRES Spectroscopy of Extragalactic HII Regions: C and O Abundances from Recombination Lines
• CHAOS I: Direct Chemical Abundances for HII Regions in NGC 628
• What Phase of the Interstellar Medium Correlates with the Star Formation Rate?
• Molecular and Atomic Gas in the Local Group Galaxy M33
• Mapping metallicity variations across nearby galaxy disks
• CHAOS III: Gas-Phase Abundances in NGC5457
• CHAOS IV: Gas-Phase Abundance Trends From The First Four CHAOS Galaxies
• The Star Formation Efficiency per Free Fall Time in Nearby Galaxies
• The metallicity gradient as a tracer of history and structure: the Magellanic Clouds and M33 galaxies
• Star formation in M33: multiwavelength signatures across the disk
• A Spectroscopic Study of Type Ibc Supernova Host Galaxies from Untargeted Surveys
• The metallicity profile of M31 from spectroscopy of hundreds of HII regions and PNe
• CHAOS II: Gas-Phase Abundances in NGC 5194
• A SINFONI Integral Field Spectroscopy Survey for Galaxy Counterparts to Damped Lyman-alpha Systems - I. New Detections and Limits for Intervening and Associated Absorbers
• Metal production in M33: space and time variations
• An Aromatic Inventory of the Local Volume
• The planetary nebula population of M33 and its metallicity gradient: A look into the galaxy's distant past
• The Yellow and Red Supergiants of M33
• The chemical composition of the Orion star-forming region: II. Stars, gas, and dust: the abundance discrepancy conundrum
• Biases in metallicity measurements from global galaxy spectra: the effects of flux-weighting and diffuse ionized gas contamination
• Early turbulent mixing as the origin of chemical homogeneity in open star clusters
• The Abundance Scatter in M33 from HII Regions: Is There Any Evidence for Azimuthal Metallicity Variations?
• The Chemical Evolution Carousel of Spiral Galaxies: Azimuthal Variations of Oxygen Abundance in NGC1365
• The effects of spatial resolution on Integral Field Spectrograph surveys at different redshifts. The CALIFA perspective
• Origin and Evolution of the Abundance Gradient along the Milky Way Disk
• The JCMT Nearby Galaxies Legacy Survey III: Comparisons of cold dust, polycyclic aromatic hydrocarbons, molecular gas, and atomic gas in NGC 2403
• The Wolf-Rayet Content of M33
• Carbon and oxygen abundance gradients in NGC300 and M33 from optical recombination lines
• A New Distance to M33 Using Blue Supergiants and the FGLR Method
• The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER) I. Ultraviolet to Infrared Photometry of 22 Million Stars in M33
• Star formation in M33: the radial and local relations with the gas
• Testing For Azimuthal Abundance Gradients In M101
• Measuring the mixing scale of the ISM within nearby spiral galaxies
• Oxygen abundance maps of CALIFA galaxies
• CHAOS VI: Direct Abundances in NGC 2403
• Mixing and transport of metals by gravitational instability-driven turbulence in galactic discs
• Evidence for azimuthal variations of the oxygen abundance gradient tracing the spiral structure of the galaxy HCG91c
• Measuring star formation with resolved observations: the test case of M33
• The Araucaria Project. A Distance Determination to the Local Group Spiral M33 from Near-Infrared Photometry of Cepheid Variables
• Revisiting the abundance gradient in the maser host galaxy NGC 4258
• Azimuthal variations of gas-phase oxygen abundance in NGC 2997
• Hubble Space Telescope Observations of Sub-Damped Lyman-alpha Absorbers at z < 0.5, and Implications for Galaxy Chemical Evolution
• Gemini GMOS spectroscopy of HeII nebulae in M33
• The UK Infrared Telescope M33 monitoring project. II. The star formation history in the central square kiloparsec
• Planetary nebulae and HII regions in the spiral galaxy NGC 300. Clues on the evolution of abundance gradients and on AGB nucleosynthesis
• CHAOS VII: A Large-Scale Direct Abundance Study in M33
• Planetary nebulae in M33: probes of AGB nucleosynthesis and ISM abundances
• Chemical Evolution Models for Spiral Disks: the Milky Way, M31 and M33
• The Resolved Distributions of Dust Mass and Temperature in Local Group Galaxies
• The UK Infrared Telescope M33 monitoring project. V. The star formation history across the galactic disc
• The Chandra ACIS Survey of M33 (ChASeM33): The final source catalog
• PINGS: the PPAK IFS Nearby Galaxies Survey
• Bar effect on gas-phase abundance gradients. I. Data sample and chemical abundances
• Spectroscopic Observation and Analysis of HII regions in M33 with MMT: Temperatures and Oxygen Abundances
• MMT Spectroscopy of Supernova Remnant Candidates in M33
• The star-formation law at GMC scales in M33, the Triangulum Galaxy
• The Carnegie Chicago Hubble Program: The Mid-Infrared Colours of Cepheids and the Effect of Metallicity on the CO Band-head at $4.6\mu$m
• High-Resolution Radiative Transfer Modelling of M33
• NRO M33 All Disk Survey of Giant Molecular Clouds (NRO MAGiC): I. HI to H_2 Transition
• The cluster birthline in M33
• The UK Infrared Telescope M33 monitoring project. I. Variable red giant stars in the central square kiloparsec
• The Nature of the Second Parameter in the IRX-beta Relation for Local Galaxies
• Deriving physical parameters of unresolved star clusters. I. Age, mass, and extinction degeneracies
• The Origin of Interstellar Turbulence in M33
• The resolved scaling relations in DustPedia: Zooming in on the local Universe
• About Metallicity Variations in the Local Galactic Interstellar Medium
• Metallicity gradients of disc stars for a cosmologically simulated galaxy
• A 2D multiwavelength study of the ionized gas and stellar population in the Giant HII Region NGC 588
• Integral field spectroscopy of HII regions in M33
• Molecular Cloud Formation and the Star Formation Efficiency in M~33
• Ionizing stellar population in the disk of NGC 3310 $-$ I. The impact of a minor merger on galaxy evolution
• The Heating of Mid-Infrared Dust in the Nearby Galaxy M33: A Testbed for Tracing Galaxy Evolution
• The oxygen abundance gradient in M81 and the robustness of abundance determinations in H II regions
• Unusually Luminous Giant Molecular Clouds in the Outer Disk of M33
• Very Massive Stars (VMS) in the Local Universe
• The Evolution and Star Formation History of M33
• Minimal HCN emission from Molecular Clouds in M33
• A spectroscopic study of blue supergiant stars in Local Group spiral galaxies: Andromeda and Triangulum
• Probing Structure in Cold Gas at $z\lesssim 1$ with Gravitationally Lensed Quasar Sight Lines
• Metallicity Measurements of Gamma-Ray Burst and Supernova Explosion Sites: Lessons from HII regions in M31
• The star-formation history of low-mass disk galaxies: a case study of NGC\,300
• High-precision abundances of first population stars in NGC 2808: confirmation of a metallicity spread
• Gas-phase Fe/O and Fe/N abundances in Star-Forming Regions. Relations between nucleosynthesis, metallicity and dust
• Using Colors to Improve Photometric Metallicity Estimates for Galaxies
• A radiative transfer model for the spiral galaxy M33
• CHAOS V: Recombination Line Carbon Abundances in M101
• Young stellar clusters and associations in M33
• A physically motivated `charge-exchange method' for measuring electron temperatures within HII regions
• Radiation fields by intermediate-age stellar populations with binaries as ionizing sources of H II regions
• The Stellar Archeology of the M33 Disk: Recent Star-Forming History and Constraints on the Timing of an Interaction with M31
• Outside-in stellar formation in the spiral galaxy M33?
• Temperature Variations of the Cold Dust in the Triangulum Galaxy M33
• The giant HII region NGC 588 as a benchmark for 2D photoionisation models
• Spectroscopic Study of M33 with LAMOST survey. I. Chemical gradients from nebulae
• Inner and outer star forming regions over the disks of spiral galaxies. I. Sample characterization
• Dissecting Galaxies with Quantitative Spectroscopy of the Brightest Stars in the Universe
• The role of environment on the star formation history of disc galaxies
• Deriving physical parameters of unresolved star clusters IV. The M33 star cluster system
• Blue luminous stars in nearby galaxies - UIT005: a possible link to the luminous blue variable stage
• A photodissociation model for the morphology of the HI near OB associations in M33
• A new method for obtaining the star formation law in galaxies
• The Lop-sided Spiral Galaxy NGC 247: Clues to a Possible Interaction with NGC 253
• Wind and nebula of the M33 variable GR290 (WR/LBV)
• Physical conditions and chemical abundances in photoionized nebulae from optical spectra
• Searching for Balmer-dominated Type Ia Supernova Remnants in M33
• Significant H I and Metal Differences around the z = 0.83 Lens Galaxy Towards the Doubly Lensed Quasar SBS 0909+532
• Hydrogen volume densities in nearby galaxies I - an automated approach
• Atomic Hydrogen produced in M33 Photodissociation Regions
• Extragalactic Planetary Nebulae: tracers of the chemical evolution of nearby galaxies
• ALMA ${}^{13}\mathrm{CO}$(J=1-0) Observations of NGC 604 in M33: Physical Properties of Molecular Clouds
• ACA CO(J=2-1) Mapping of the Nearest Spiral Galaxy M33. II. Exploring the Evolution of Giant Molecular Clouds
• A multiwavelength analysis of the clumpy FIR-bright sources in M33
• SIGNALS of Giant HII Regions: A Spatially Resolved Analysis of NGC 604
• Molecular cloud matching in CO and dust in M33 II. Physical properties of giant molecular clouds
• Testing Evolutionary Models with Red Supergiant and Wolf-Rayet Populations
• Massive stars in the nuclei and arms of spirals
• A Metallicity Map of M33
• The IRAM M33 CO(2-1) Survey - A complete census of the molecular gas out to 7 kpc
• Chemical abundances in Seyfert galaxies -- VII. Direct abundance determination of neon based on optical and infrared emission lines
• M^3D: Mosaicking M33 with MUSE datacubes I. Unveiling the diversity of HII regions in M33 with MUSE