Spectroscopic Observation and Analysis of HII regions in M33 with MMT: Temperatures and Oxygen Abundances

Abstract

The spectra of 413 star-forming (or HII) regions in M33 (NGC 598) were observed by using the multifiber spectrograph of Hectospec at the 6.5-m Multiple Mirror Telescope (MMT). By using this homogeneous spectra sample, we measured the intensities of emission lines and some physical parameters, such as electron temperatures, electron densities, and metallicities. Oxygen abundances were derived via the direct method (when available) and two empirical strong-line methods, namely, O3N2 and N2. In the high-metallicity end, oxygen abundances derived from O3N2 calibration were higher than those derived from N2 index, indicating an inconsistency between O3N2 and N2 calibrations. We presented a detailed analysis of the spatial distribution of gas-phase oxygen abundances in M33 and confirmed the existence of the axisymmetric global metallicity distribution widely assumed in literature. Local variations were also observed and subsequently associated with spiral structures to provide evidence of radial migration driven by arms. Our O/H gradient fitted out to 1.1 $R_{25}$ resulted in slopes of $-0.17\pm 0.03$, $-0.19\pm 0.01$, and $-0.16\pm 0.17$ dex $R_{25}^{-1}$ utilizing abundances from O3N2, N2 diagnostics, and direct method, respectively.

Accepted for publication in ApJ

References in corpus (12)

• The GALEX Ultraviolet Atlas of Nearby Galaxies
• PyNeb: a new tool for analyzing emission lines. I. Code description and validation of results
• Extragalactic chemical abundances: do HII regions and young stars tell the same story? The case of the spiral galaxy NGC 300
• 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
• The M33 Metallicity Project: Resolving the Abundance Gradient Discrepancies in M33
• Spiral-induced velocity and metallicity patterns in a cosmological zoom simulation of a Milky Way-sized galaxy
• Carbon and oxygen abundance gradients in NGC300 and M33 from optical recombination lines
• Evidence of ongoing radial migration in NGC 6754: Azimuthal variations of the gas properties
• Evidence for azimuthal variations of the oxygen abundance gradient tracing the spiral structure of the galaxy HCG91c
• Chandra ACIS Survey of M33 (ChASeM33): A First Look
• Gas-phase oxygen abundances and radial metallicity gradients in the two nearby spiral galaxies NGC7793 and NGC4945

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