Density biases and temperature relations for DESIRED HII regions

Abstract

We present a first study based on the analysis of the DEep Spectra of Ionized REgions Database (DESIRED). This is a compilation of 190 high signal-to-noise ratio optical spectra of HII regions and other photoionized nebulae, mostly observed with 8-10m telescopes and containing $\sim$29380 emission lines. We find that the electron density --$n_{\mathrm{e}}$-- of the objects is underestimated when [SII] $\lambda 6731/\lambda 6716$ and/or [OII] $\lambda 3726/\lambda 3729$ are the only density indicators available. This is produced by the non-linear density dependence of the indicators in the presence of density inhomogeneities. The average underestimate is $\sim 300$ cm${}^{-3}$ in extragalactic HII regions, introducing systematic overestimates of $T_{\mathrm{e}}$([OII]) and $T_{\mathrm{e}}$([SII]) compared to $T_{\mathrm{e}}$([NII]). The high-sensitivity of [OII] $\lambda \lambda 7319+20+30+31/\lambda \lambda 3726+29$ and [SII] $\lambda \lambda 4069+76/\lambda \lambda 6716+31$ to density makes them more suitable for the diagnosis of the presence of high-density clumps. If $T_{\mathrm{e}}$([NII]) is adopted, the density underestimate has a small impact in the ionic abundances derived from optical spectra, being limited to up to $\sim$0.1 dex when auroral [SII] and/or [OII] lines are used. However, these density effects are critical for the analysis of infrared fine structure lines, such as those observed by the JWST in local star forming regions, implying strong underestimates of the ionic abundances. We present temperature relations between $T_{\mathrm{e}}$([OIII]), $T_{\mathrm{e}}$([ArIII]), $T_{\mathrm{e}}$([SIII]) and $T_{\mathrm{e}}$([NII]) for the extragalactic HII regions. We confirm a non-linear dependence between $T_{\mathrm{e}}$([OIII])-$T_{\mathrm{e}}$([NII]) due to a more rapid increase of $T_{\mathrm{e}}$([OIII]) at lower metallicities.

Accepted for publication in MNRAS

References in corpus (51)

• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• PyNeb: a new tool for analyzing emission lines. I. Code description and validation of results
• The SAMI Galaxy Survey: instrument specification and target selection
• Extragalactic chemical abundances: do HII regions and young stars tell the same story? The case of the spiral galaxy NGC 300
• The primordial abundance of 4He: a self-consistent empirical analysis of systematic effects in a large sample of low-metallicity HII regions
• Keck HIRES Spectroscopy of Extragalactic HII Regions: C and O Abundances from Recombination Lines
• The MagE Spectrograph
• CHAOS I: Direct Chemical Abundances for HII Regions in NGC 628
• Mapping metallicity variations across nearby galaxy disks
• The localized chemical pollution in NGC 5253 revisited: Results from deep echelle spectrophotometry
• Nebular spectroscopy: A guide on H II regions and planetary nebulae
• Precision abundance analysis of bright HII galaxies
• Carbon and oxygen abundances from recombination lines in low-metallicity star-forming galaxies. Implications for chemical evolution
• Properties of the ionized gas in HH202. II: Results from echelle spectrophotometry with UVES
• Binarity and the abundance discrepancy problem in planetary nebulae
• Faint emission lines in the Galactic H II regions M16, M20 and NGC 3603
• The temperature and ionization structure of the emitting gas in HII galaxies: Implications for the accuracy of abundance determinations
• Chemical abundances for Hf 2-2, a planetary nebula with the strongest known heavy element recombination lines
• The PHANGS-MUSE Nebula Catalogue
• The radial abundance gradient of oxygen towards the Galactic anticentre
• Determination of the primordial helium abundance based on NGC 346 an HII region of the Small Magellanic Cloud
• Spectroscopy of two PN candidates in IC10
• Temperature inhomogeneities cause the abundance discrepancy in H II regions
• Ionization correction factors and dust depletion patterns in giant HII regions
• Comparing the pre-SNe feedback and environmental pressures for 6000 HII regions across 19 nearby spiral galaxies
• On the radial abundance gradients of nitrogen and oxygen in the inner Galactic disc
• CHAOS VII: A Large-Scale Direct Abundance Study in M33
• Census of HII regions in NGC 6754 derived with MUSE: Constraints on the metal mixing scale
• Carbon, nitrogen and oxygen abundance gradients in M101 and M31
• The Te[N II]-Te[O III] temperature relation in H II regions and the reliability of strong-line methods
• On the relation between electron temperatures in the O+ and O++ zones in high-metallicity HII regions
• An Introduction to Galactic Chemical Evolution
• MUSE spectroscopy of planetary nebulae with high abundance discrepancies
• A Machine Learning Artificial Neural Network Calibration of the Strong-Line Oxygen Abundance
• C/O ratios in planetary nebulae with dual-dust chemistry from faint optical recombination lines
• On the electron temperature determination in high-metallicity HII regions
• The Cocoon Nebula and its ionizing star: do stellar and nebular abundances agree?
• The homogeneity of chemical abundances in H II regions of the Magellanic Clouds
• The planetary nebula IC 4776 and its post-common-envelope binary central star
• Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy I: HH529II and III
• A geostatistical analysis of multiscale metallicity variations in galaxies [I]: Introduction and comparison of high-resolution metallicity maps to an analytic metal transport model
• Helium abundances and its radial gradient from the spectra of HII regions and ring nebulae of the Milky Way
• Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy II: HH204
• Neutron-capture element abundances in the planetary nebula NGC 5315 from deep optical and near-infrared spectrophotometry
• Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy III: HH514
• Atomic Data Assessment with PyNeb: Radiative and Electron Impact Excitation Rates for [Fe II] and [Fe III]
• The impact of spectra quality on nebular abundances
• CHAOS V: Recombination Line Carbon Abundances in M101
• Physical conditions and chemical abundances in PN M 2-36. Results from deep echelle observations
• Atomic data and the density structures of planetary nebulae
• Backscattering and Line Broadening in Orion

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