SDSS-V LVM: Resolving Physical Conditions in the Trifid Nebula
arXiv:2512.02802 · doi:10.1051/0004-6361/202558091
Abstract
The chemical abundance of the interstellar medium sets the initial conditions for star formation and provides a probe of chemical galaxy evolution models. However, unresolved inhomogeneities in the electron temperature can lead to a systematic underestimation of the abundances. We aim to directly test this effect. We use the SDSS-V Local Volume Mapper to spatially map the physical conditions of the Trifid Nebula (M 20), a Galactic H II region ionized by a single mid-type O star, at 0.24 pc resolution. We exploit various emission lines (e.g., Hydrogen recombination lines and collisionally excited lines, including also faint auroral lines) and compute spatially resolved maps of [O II] and [S II] electron densities; [N II], [O II], [S II], [S III] electron temperatures; and the ionic oxygen abundances. We find internal variations of electron density that result from the ionization front, along with a negative radial gradient. However, we do not find strong gradients or structures in the electron temperature and the total oxygen abundance, making the Trifid Nebula a relatively homogeneous H II region at the observed spatial scale. We compare these spatially resolved properties with equivalent integrated measurements of the Trifid Nebula and find no significant variations between integrated and spatially resolved conditions. This isolated H II region, ionized by a single O-star, represents a test case of an ideal Strömgren sphere. The physical conditions in the Trifid Nebula behave as expected, with no significant differences between integrated and resolved measurements.
accepted for publication in A&A
References in corpus (61)
- Star Formation in Galaxies Along the Hubble Sequence
- LSST: from Science Drivers to Reference Design and Anticipated Data Products
- Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
- The chemical make-up of the Sun: A 2020 vision
- De Re Metallica: The cosmic chemical evolution of galaxies
- PyNeb: a new tool for analyzing emission lines. I. Code description and validation of results
- Understanding Galaxy Evolution through Emission Lines
- The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars
- Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models
- Atmospheric NLTE-Models for the Spectroscopic Analysis of Blue Stars with Winds. II. Line-Blanketed Models
- The birth of the Milky Way as uncovered by accurate stellar ages with Gaia
- Nebular spectroscopy: A guide on H II regions and planetary nebulae
- Cloud-cloud collisions and triggered star formation
- Ionized gaseous nebulae chemical abundance determination using the direct method
- Testing massive star evolution, star-formation history and feedback at low metallicity : Spectroscopic analysis of OB stars in the SMC Wing
- Molecular clouds in the Trifid nebula M20; Possible evidence for a cloud-cloud collision in triggering the formation of the first generation stars
- Hydrodynamics of Cometary Compact HII Regions
- Properties of the ionized gas in HH202. II: Results from echelle spectrophotometry with UVES
- Theoretical ISM pressure and electron density diagnostics for local and high-redshift galaxies
- Triggered O star formation in M20 via cloud-cloud collision: Comparisons between high-resolution CO observations and simulations
- The MiMeS Survey of Magnetism in Massive Stars: CNO surface abundances of Galactic O stars
- 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 [Fe IV] Discrepancy: Constraining the Iron Abundances in Nebulae
- The chemical composition of the Orion star-forming region: II. Stars, gas, and dust: the abundance discrepancy conundrum
- Photoionisation Feedback in a Self-Gravitating, Magnetised, Turbulent Cloud
- The Ionized Gas in Nearby Galaxies as Traced by the [NII] 122 and 205 μm Transitions
- The radial abundance gradient of oxygen towards the Galactic anticentre
- A Multiwavelength Look at Galactic Massive Star Forming Regions
- Gradients of chemical abundances in the Milky Way from HII regions: distances derived from Gaia EDR3 parallaxes and temperature inhomogeneities
- Helium recombination spectra as temperature diagnostics for planetary nebulae
- Temperature inhomogeneities cause the abundance discrepancy in H II regions
- Spectacular Spitzer images of the Trifid Nebula: Protostars in a young, massive-star-forming region
- Density biases and temperature relations for DESIRED HII regions
- Spatially resolved study of the physical properties of the ionized gas in NGC 595
- Deviations from He I Case B Recombination Theory and Extinction Corrections in the Orion Nebula
- Variation of the extinction law in the Trifid nebula
- PPAK Integral Field Spectroscopy survey of the Orion Nebula: Data Release
- Chandra Observation of the Trifid Nebula: X-ray emission from the O star complex and actively forming pre-main sequence stars
- Calibrating Interstellar Abundances using SNR Radiative Shocks
- Atomic Data Assessment with PyNeb
- Integral Field Spectroscopy of HII region complexes. The outer disk of NGC 6946
- Radial abundance gradients in the outer Galactic disk as traced by main-sequence OB stars
- Connecting the dots: a correlation between ionising radiation and cloud mass-loss rate traced by optical integral field spectroscopy
- X-rays and Protostars in the Trifid Nebula
- A GMOS-N IFU study of the central H II region in the blue compact dwarf galaxy NGC 4449: Kinematics, Nebular Metallicity and Star-Formation
- Turbulence in the Ionized Gas of the Orion Nebula
- NGC 5746: formation history of a massive disc-dominated galaxy
- Integral field spectroscopy of HII regions in M33
- Structure and Physical Conditions in the Huygens Region of the Orion Nebula
- The Nature and Frequency of Outflows from Stars in the Central Orion Nebula Cluster
- SDSS-V Local Volume Mapper (LVM): A Glimpse into Orion
- HST and UKIRT Observations of the Center of the Trifid Nebula: Evidence for the Photoevaporation of a Proplyd and a Protostellar Condensation
- Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy III: HH514
- No temperature fluctuations in the giant HII region H 1013
- A global view on star formation: The GLOSTAR Galactic plane survey X. Galactic HII region catalog using radio recombination lines
- Spitzer observations of extragalactic H II regions - III. NGC 6822 and the hot star, H II region connection
- pySTARBURST99: The Next Generation of STARBURST99
- The Effect of Molecular Cloud Properties on the Kinematics of Stars Formed in the Trifid Region
- The Young Stellar Population, Distance, and Cloud-Cloud Collision Induced Star Formation Scenario of the Trifid Nebula