SIGNALS of Giant HII Regions: A Spatially Resolved Analysis of NGC 604

Abstract

Observing giant HII regions at fine spatial scales uncovers detailed structures and reveals variations in ionization, abundance, and dynamical properties of ionized gas and the effect of stellar feedback. Using emission line data of M33 observed with SITELLE as part of the Star-formation, Ionized Gas, and Nebular Abundances Legacy Survey (SIGNALS), we present maps of the principal optical emission line ratios for NGC 604, the most luminous HII region in M33. The excitation maps align well with the H$\alpha$ morphology and are clearly related to the location of the central stellar cluster and secondary stellar groups. The maps of ionization-sensitive line ratios show substantial variations across the face of NGC 604. We demonstrate that these variations are unlikely to be due to chemical inhomogeneities but are primarily caused by changes in ionization, which in turn affect the observed line ratios. We present the H$\alpha$ kinematics of the region and connect it to the excitation structure, showing how the dynamic motions influence the spatial distribution of ionized gas. We note two distinct sources identified in these excitation maps: a known supernova remnant and a previously unknown planetary nebula. Such parsec-scale features contribute only a small percentage to the overall light and would remain undetected without the use of high-resolution spatial data. Throughout the paper, we make comparisons to and raise concerns about single-aperture and long-slit spectroscopic measurements of giant HII regions, highlighting the limitations and potential inaccuracies of such methods.

arXiv comment26 pages, 11 figures, 3 tables. Accepted to ApJ

References in corpus (90)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• On the variation of the Initial Mass Function
• The Gaia mission
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• The Global Schmidt Law in Star Forming Galaxies
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Gaia Data Release 3: Summary of the content and survey properties
• The Host Galaxies of AGN
• Theoretical Modeling of Starburst Galaxies
• The Host Galaxies and Classification of Active Galactic Nuclei
• [O III]/[N II] as an Abundance Indicator at High Redshift
• Metallicity Calibrations and the Mass-Metallicity Relation for Star-Forming Galaxies
• CALIFA, the Calar Alto Legacy Integral Field Area survey: I. Survey presentation
• Using Strong Lines to Estimate Abundances in Extragalactic HII Regions and Starburst Galaxies
• A new calibration of stellar parameters of Galactic O stars
• Galactic Chemical Evolution: Hydrogen Through Zinc
• Calibrating Extinction-Free Star Formation Rate Diagnostics with 33GHz Free-Free Emission in NGC6946
• Metallicities of 0.3<z<1.0 Galaxies in the GOODS-North Field
• De Re Metallica: The cosmic chemical evolution of galaxies
• PyNeb: a new tool for analyzing emission lines. I. Code description and validation of results
• The O3N2 and N2 abundance indicators revisited: improved calibrations based on CALIFA and Te-based literature data
• Optical Spectroscopy and Nebular Oxygen Abundances of the Spitzer/SINGS Galaxies
• Understanding Galaxy Evolution through Emission Lines
• Spectroscopy of Outlying H II Regions in Spiral Galaxies: Abundances and Radial Gradients
• Realistic Ionizing Fluxes for Young Stellar Populations from 0.05 to twice solar metallicity
• New Strong Line Abundance Diagnostics for \HII Regions: Effects of $\kappa$-Distributed Electron Energies and New Atomic Data
• Chemical abundances in high-redshift galaxies: A powerful new emission line diagnostic
• Galaxy-Wide Shocks in Late-Merger Stage Luminous Infrared Galaxies
• Giant Molecular Clouds in M33 - I. BIMA All Disk Survey
• On the oxygen abundance determination in HII regions: High - metallicity regions
• Planetary Nebulae: Observational Properties, Mimics, and Diagnostics
• Keck HIRES Spectroscopy of Extragalactic HII Regions: C and O Abundances from Recombination Lines
• The Optical Depth of H II Regions in the Magellanic Clouds
• CHAOS I: Direct Chemical Abundances for HII Regions in NGC 628
• The M33 Metallicity Project: Resolving the Abundance Gradient Discrepancies in M33
• CHAOS IV: Gas-Phase Abundance Trends From The First Four CHAOS Galaxies
• The oxygen abundance in the inner HII regions of M101. Implications for the calibration of strong-line metallicity indicators
• Collision Strengths for [O III] Optical and Infrared Lines
• Abundance scaling in stars, nebulae and galaxies
• Massive star formation in Wolf-Rayet galaxies. IV: Colours, chemical composition analysis and metallicity-luminosity relations
• The Chandra ACIS Survey of M33: X-ray, Optical and Radio Properties of the Supernova Remnants
• Composite Spectra in Merging U/LIRGs Caused by Shocks
• Star Formation in Luminous HII regions in M33
• Oxygen Abundances and Chemical Evolution in Low Surface Brightness Galaxies
• An Empirical Test and Calibration of H II Region Diagnostics
• The Wolf-Rayet Content of M33
• SITELLE: An Imaging Fourier Transform Spectrometer for the Canada-France-Hawaii Telescope
• The massive stellar content in NGC604 and its evolutionary state
• A Reexamination of Electron Density Diagnostics for Ionized Gaseous Nebulae
• The Hubble Space Telescope Survey of M31 Satellite Galaxies I. RR Lyrae-based Distances and Refined 3D Geometric Structure
• SIGNALS: I. Survey Description
• NGC 604, the Scaled OB Association (SOBA) Prototype. I: Spatial Distribution of the Different Gas Phases and Attenuation by Dust
• Calibration of Nebular Emission-line Diagnostics: II. Abundances
• NGC628 with SITELLE : I. Imaging Spectroscopy of 4285 HII region candidates
• The internal dynamical equilibrium of HII regions: a statistical study
• Kinematics and Mass Modeling of Messier 33: Halpha observations
• Optimal fitting of gaussian-apodized or under-resolved emission lines in Fourier Transform spectra providing new insights on the velocity structure of NGC 6720
• Spatially resolved study of the physical properties of the ionized gas in NGC 595
• PPAK Integral Field Spectroscopy survey of the Orion Nebula: Data Release
• CHAOS VII: A Large-Scale Direct Abundance Study in M33
• Atomic Data Assessment with PyNeb
• Narrowband CCD Photometry of Giant HII Regions
• Structure and Feedback in 30 Doradus I: Observations
• A SITELLE view of M31's central region - I: Calibrations and radial velocity catalogue of nearly 800 emission-line point-like sources
• MMT Spectroscopy of Supernova Remnant Candidates in M33
• Resolving Ionisation and Metallicity on Parsec Scales Across Mrk 71 with HST-WFC3
• The red supergiants & Wolf-Rayet stars of NGC 604
• STIS Spectral Imagery of the OB Stars in NGC 604: The Most Luminous Stars
• Wolf-Rayet Stars in M33 II: Optical Spectroscopy of emission-line stars in Giant Hii Regions
• A 2D multiwavelength study of the ionized gas and stellar population in the Giant HII Region NGC 588
• Correlation between the gas-phase metallicity and ionization parameter in extragalactic HII regions
• SDSS-V Local Volume Mapper (LVM): A Glimpse into Orion
• On the ongoing multiple blowout in NGC 604
• Unresolved Wind-Driven Shells and the Supersonic Velocity Dispersion in Giant HII Regions
• Theoretically Modelling Photoionized Regions with Fractal Geometry in Three Dimensions
• Structure, Velocity Field and Turbulence in NGC 604
• The Chandra ACIS Survey of M33 (ChASeM33): Investigating the Hot Ionized Medium in NGC604
• Aperture Synthesis Observations of CO, HCN, and 89GHz Continuum Emission toward NGC 604 in M 33: Sequential Star Formation Induced by Supergiant Hii region
• Star-Forming Environments Throughout the M101 Group
• Ongoing Massive Star Formation in NGC 604
• Deep Narrowband Photometry of the M101 Group: Strong-Line Abundances of 720 HII Regions
• Nebular abundances in galaxies: Beware of biases
• Internal Variations in Empirical Oxygen Abundances for Giant HII Regions in the Galaxy NGC 2403
• The giant HII region NGC 588 as a benchmark for 2D photoionisation models
• A photoionization model of the spatial distribution of the optical and mid-IR properties in NGC595
• Unveiling the new generation of stars in NGC 604 with Gemini-NIRI
• A First-look at Spatially-resolved Infrared Supernova Remnants in M33 with JWST