The radial abundance gradient of chlorine in the Milky Way

Esteban, C.; García‐Rojas, J.; Pérez-Mesa, V.

doi:10.1093/mnras/stv1367

Cited by 38 publications

(64 citation statements)

References 52 publications

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“…The atomic data listed in Table 6 are adopted in our spectral analysis. The physical conditions and the ionic and elemental abundances of oxygen of M20, M16, M17, M8, NGC 3576, M42, NGC 3603, Sh 2-311 and NGC 2579 were determined by Esteban et al (2015) using the same procedure and atomic data as for our current sample. The same method was applied to the analysis of NGC 7635, which was published in Esteban et al (2016b).…”

Section: Resultsmentioning

confidence: 99%

The radial abundance gradient of oxygen towards the Galactic anti-centre

Esteban

Fang

García‐Rojas

et al. 2017

Monthly Notices of the Royal Astronomical Society

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103

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We present deep optical spectroscopy of eight H ii regions located in the anticentre of the Milky Way. The spectra were obtained at the 10.4m GTC and 8.2m VLT. We determined T e ([N ii]) for all objects and T e ([O iii]) for six of them. We also included in our analysis an additional sample of 13 inner-disc Galactic H ii regions from the literature that have excellent T e determinations. We adopted the same methodology and atomic dataset to determine the physical conditions and ionic abundances for both samples. We also detected the C ii and O ii optical recombination lines in Sh 2-100, which enables determination of the abundance discrepancy factor for this object. We found that the slopes of the radial oxygen gradients defined by the H ii regions from R 25 (= 11.5 kpc) to 17 kpc and those within R 25 are similar within the uncertainties, indicating the absence of flattening in the radial oxygen gradient in the outer Milky Way. In general, we found that the scatter of the O/H ratios of H ii regions is not substantially larger than the observational uncertainties. The largest possible local inhomogeneities of the oxygen abundances are of the order of 0.1 dex. We also found positive radial gradients in T e ([O iii]) and T e ([N ii]) across the Galactic disc. The shapes of these temperature gradients are similar and also consistent with the absence of flattening of the metallicity distribution in the outer Galactic disc.

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Section: Resultsmentioning

confidence: 99%

The radial abundance gradient of oxygen towards the Galactic anti-centre

Esteban

Fang

García‐Rojas

et al. 2017

Monthly Notices of the Royal Astronomical Society

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103

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“…The chlorine-oxygen relation among the M31 PNe alone has large scatter, probably much affected by large uncertainties, given the weakness of the [Cl iii] lines. Using the Galactic H ii regions from Esteban et al (2015, including the Orion Nebula) as a baseline for correlation, we found that not all M31 PNe are located along this relation within the errors.…”

Section: Emission Features Of [Wr] Central Starsmentioning

confidence: 89%

Chemical Abundances of Planetary Nebulae in the Substructures of M31. II. The Extended Sample and a Comparison Study with the Outer-disk Group*

Fang

García-Benito

Guerrero

et al. 2018

ApJ

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We report deep spectroscopy of ten planetary nebulae (PNe) in the Andromeda Galaxy (M31) using the 10.4 m GTC. Our targets reside in different regions of M31, including halo streams and dwarf satellite M32, and kinematically deviate from the extended disk. The temperature-sensitive [O iii] λ4363 line is observed in all PNe. For four PNe, the GTC spectra extend beyond 1 µm, enabling explicit detection of the [S iii] λ6312 and λλ9069,9531 lines and thus determination of the [S iii] temperature. Abundance ratios are derived and generally consistent with AGB model predictions. Our PNe probably all evolved from low-mass (<2 M ) stars, as analyzed with the most up-to-date post-AGB evolutionary models, and their main-sequence ages are mostly ∼2-5 Gyr. Compared to the underlying, smooth, metal-poor halo of M31, our targets are uniformly metal-rich ([O/H] −0.4), and seem to resemble the younger population in the stream. We thus speculate that our halo PNe formed in the Giant Stream's progenitor through extended star formation. Alternatively, they might have formed from the same metal-rich gas as did the outer-disk PNe, but was displaced into their present locations as a result of galactic interactions. These interpretations are, although speculative, qualitatively in line with the current picture, as inferred from previous wide-field photometric surveys, that M31's halo is the result of complex interactions and merger processes. The behavior of N/O of the combined sample of the outer-disk and our halo/substructure PNe signifies that hot bottom burning might actually occur at <3 M , but careful assessment is needed.

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“…Piece-wise linear fits to the bulk trends are appropriate to describe the scaling relations. The circles are gas-phase Milky Way nebular data from Esteban et al (2015). The dots are from gas-phase nebular data from Izotov & Thuan (2004) (blue, Blue Compact Galaxies) and Izotov et al (2006) (black, metal poor emission line galaxies).…”

Section: General Approachmentioning

confidence: 99%

Abundance scaling in stars, nebulae and galaxies

Nicholls¹,

Sutherland²,

Dopita³

et al. 2016

Mon. Not. R. Astron. Soc.

116

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We present a new basis for scaling abundances with total metallicity in nebular photoionisation models, based on extensive Milky Way stellar abundance data, to replace the uniform scaling normally used in the analysis of H ii regions. Our goal is to provide a single scaling method and local abundance reference standard for use in nebular modelling and its key inputs, the stellar atmosphere and evolutionary track models. We introduce a parametric enrichment factor, ζ, to describe how atomic abundances scale with total abundance, and which allows for a simple conversion between scales based on different reference elements (usually oxygen or iron) . The models and parametric description provide a more physically realistic approach than simple uniform abundance scaling. With appropriate parameters, the methods described here may be applied to H ii regions in the Milky Way, large and dwarf galaxies in the local universe, Active Galactic Nuclei (AGNs), and to star forming regions at high redshift.

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The radial abundance gradient of chlorine in the Milky Way

Cited by 38 publications

References 52 publications

The radial abundance gradient of oxygen towards the Galactic anti-centre

The radial abundance gradient of oxygen towards the Galactic anti-centre

Chemical Abundances of Planetary Nebulae in the Substructures of M31. II. The Extended Sample and a Comparison Study with the Outer-disk Group*

Abundance scaling in stars, nebulae and galaxies

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