Pulsational constraints to the metallicity gradient in the Galactic disk

Caputo, F.; Marconi, M.; Musella, I.; Pont, F.

doi:10.1051/0004-6361:20010479

Cited by 43 publications

(46 citation statements)

References 22 publications

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“…Data on cepheid variables should in principle agree with the B star results, which is confirmed by a recent analysis by Caputo et al (2001), but a flatter gradient and/or a discontinuity around 10 kpc is suggested from the high resolution data by Andrievsky et al (2002).…”

Section: Abundance Gradients From Pnsupporting

confidence: 80%

PN and Galactic Chemical Evolution

Maciel¹,

Costa²

2003

Symp. - Int. Astron. Union

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Section: Abundance Gradients From Pnsupporting

confidence: 80%

PN and Galactic Chemical Evolution

Maciel¹,

Costa²

2003

Symp. - Int. Astron. Union

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“…4) with the possible occurrence either of a change in the slope or of a shoulder for 7 ≤ R G ≤10 kpc, as suggested by Twarog et al (1997); Caputo et al (2001), and Andrievsky et al (2004).…”

Section: The Iron Abundance Gradientmentioning

confidence: 90%

On the fine structure of the Cepheid metallicity gradient in the Galactic thin disk

Genovali

Lemasle

Bono

et al. 2014

A&A

188

262

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We present homogeneous and accurate iron abundances for 42 Galactic Cepheids based on high resolution (R ∼ 38 000) high signal-to-noise ratio (S /N ≥ 100) optical spectra collected with UVES at VLT (128 spectra). The above abundances were complemented with high-quality iron abundances provided either by our group (86) or available in the literature. We were careful to derive a common metallicity scale and ended up with a sample of 450 Cepheids. We also estimated accurate individual distances for the entire sample by using homogeneous near-infrared photometry and the reddening free period-Wesenheit relations. The new metallicity gradient is linear over a broad range of Galactocentric distances (R G ∼ 5-19 kpc) and agrees quite well with similar estimates available in the literature (-0.060 ± 0.002 dex/kpc). We also uncover evidence that suggests that the residuals of the metallicity gradient are tightly correlated with candidate Cepheid groups (CGs). The candidate CGs have been identified as spatial overdensities of Cepheids located across the thin disk. They account for a significant fraction of the residual fluctuations, and also for the large intrinsic dispersion of the metallicity gradient. We performed a detailed comparison with metallicity gradients based on different tracers: OB stars and open clusters. We found very similar metallicity gradients for ages younger than 3 Gyr, while for older ages we found a shallower slope and an increase in the intrinsic spread. The above findings rely on homogeneous age, metallicity, and distance scales. Finally, by using a large sample of Galactic and Magellanic Cepheids for which accurate iron abundances are available, we found that the dependence of the luminosity amplitude on metallicity is vanishing.

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“…The metallicity is converted onto the Z scale using the relation; log Z = [Fe/H] − 1.7 (Fig. 5 of Caputo et al 2001 show this for LMC, SMC and Galactic Cepheids). Two sets of isochrones are produced; the first, younger set covers log (t/yr) = 9.1−9.4 with Z = 0.0125 and the second, older set covers log (t/yr) = 9.4−9.7 with Z = 0.0033 (log (t/yr) = 9.4 appears in both due to the SFH histogram bins overlapping).…”

Section: Reddening Valuesmentioning

confidence: 99%

The VMC survey

Tatton

Loon

Cioni

et al. 2013

A&A

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Context. The details of how galaxies have evolved over cosmological times are imprinted in their star formation history, chemical enrichment and morpho-kinematic structure. Parameters behind these, such as effective temperature and metallicity, can be measured by combining photometric techniques with modelling. However, there are uncertainties with this indirect approach from the ambiguity of colour and magnitude and the effects of interstellar reddening. Aims. In this paper we present a detailed reddening map of the central 30 Doradus region of the Large Magellanic Cloud; for both community use and as a test of the methods used for future use on a wider area. The reddening, a measurement of dust extinction, acts as a tracer of the interstellar medium (ISM). Methods. Near-infrared (NIR) photometry of the red clump stars is used to measure reddening as their fixed luminosity and intermediate age make extinction the dominant cause of colour and magnitude variance. The star formation history derived previously from these data is used to produce an intrinsic colour to act as a zero point in converting colour to reddening values E(J − K s ) which are subsequently converted to visual extinction A V . Results. Presented is a dust map for the 30 Doradus field in both A V and E(J − K s ). This map samples a region of 1 • × 1.• 5, containing ∼1.5 × 10 5 red clump stars which probe reddening up to A V 6 mag. We compare our map with maps from the literature, including optical extinction maps and radio, mid-and far-infrared maps of atomic hydrogen and dust emission. Through estimation of column density we locate molecular clouds. Conclusions. This new reddening map shows correlation with equivalent maps in the literature, validating the method of red clump star selection. We make our reddening map available for community use. In terms of ISM the red clump stars appear to be more affected by the cooler dust measured by 70 μm emission because there is stronger correlation between increasing emission and extinction due to red clump stars not being located near hot stars that would heat the dust. The transition from atomic hydrogen to molecular hydrogen occurs between densities of N H 4 × 10 21 cm −2 and N H 6 × 10 21 cm −2 .

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Pulsational constraints to the metallicity gradient in the Galactic disk

Cited by 43 publications

References 22 publications

PN and Galactic Chemical Evolution

PN and Galactic Chemical Evolution

On the fine structure of the Cepheid metallicity gradient in the Galactic thin disk

The VMC survey

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