The galactic abundance gradient from Cepheids

Luck, R. E.; Gieren, W.; Andrievsky, S. M.; Kovtyukh, V. V.; Fouqué, P.; Pont, F.; Kienzle, F.

doi:10.1051/0004-6361:20030155

Cited by 132 publications

(192 citation statements)

References 15 publications

Supporting

Mentioning

177

Contrasting

Order By: Relevance

“…For the solar neighbourhood, the data were compiled from several authors (Bensby & Feltzing 2006;Ecuvillon et al 2004;Fabbian et al 2009a;Gratton et al 2000;Gustafsson et al 1999, Jonsell et al 2005, Spite et al 2005, while the Cepheid abundances in Fig. 7 were taken from the works by Andrievski et al (2002aAndrievski et al ( ,b,c, 2004 and Luck et al (2003Luck et al ( , 2006. The observed G-dwarf distributions used in this paper were taken from Edvardsson et al (1993) and Wyse & Gilmore (1995).…”

Section: Abundance Datamentioning

confidence: 99%

The origin of carbon: Low-mass stars and an evolving, initially top-heavy IMF?

Mattsson

2010

A&A

View full text Add to dashboard Cite

Multi-zone chemical evolution models (CEMs), differing in the nucleosynthesis prescriptions (yields) and prescriptions of star formation, have been computed for the Milky Way. All models fit the observed O/H and Fe/H gradients well and reproduce the main characteristics of the gas distribution, but they are also designed to do so. For the C/H gradient the results are inconclusive with regards to yields and star formation. The C/Fe and O/Fe vs. Fe/H, as well as C/O vs. O/H trends predicted by the models for the solar neighbourhood zone were compared with stellar abundances from the literature. For O/Fe vs. Fe/H all models fit the data, but for C/O vs. O/H, only models with increased carbon yields for zero-metallicity stars or an evolving initial mass function provide good fits. Furthermore, a steep star formation threshold in the disc can be ruled out since it predicts a steep fall-off in all abundance gradients beyond a certain galactocentric distance (∼13 kpc) and cannot explain the possible flattening of the C/H and Fe/H gradients in the outer disc seen in observations. Since in the best-fit models the enrichment scenario is such that carbon is primarily produced in low-mass stars, it is suggested that in every environment where the peak of star formation happened a few Gyr back in time, winds of carbon-stars are responsible for most of the carbon enrichment. However, a significant contribution by zero-metallicity stars, especially at very early stages, and by winds of high-mass stars, which are increasing in strength with metallicity, cannot be ruled out by the CEMs presented here. In the solar neighbourhood, as much as 80%, or as little as 40% of the carbon may have been injected to the interstellar medium by low-and intermediate-mass stars. The stellar origin of carbon remains an open question, although production in low-and intermediate-mass stars appears to be the simplest explanation of observed carbon abundance trends.

show abstract

Section: Abundance Datamentioning

confidence: 99%

The origin of carbon: Low-mass stars and an evolving, initially top-heavy IMF?

Mattsson

2010

A&A

View full text Add to dashboard Cite

show abstract

“…For Cepheids belonging to spectroscopic binary systems, the amplitude of the radial velocity variations of pulsational origin was determined by removing the orbital effect from the radial velocity data based on the orbital elements available in the online database 1 of binary Cepheids (Szabados 2003b Giridhar (1983), Fry & Carney (1997), Groenewegen et al (2004), Andrievsky et al (2002a,b,c), Luck et al (2003), Andrievsky et al (2004Andrievsky et al ( , 2005, Kovtyukh et al (2005a,b), Romaniello et al (2005), Mottini (2006), Yong et al (2006), and Lemasle et al (2007).…”

Section: Pulsation Amplitudesmentioning

confidence: 99%

“…To homogenize the scale of [Fe/H] values, data were shifted to a common solar metallicity, log[n(Fe)] = 7.45 on a scale where log[n(H)] = 12 (Grevesse et al 2007). Most [Fe/H] data have been taken from Andrievsky and his collaborators' papers (Andrievsky et al 2002a,b,c;Luck et al 2003;Andrievsky et al 2004Andrievsky et al , 2005Kovtyukh et al 2005a,b). Their scale was shifted by 0.05 because they used an earlier [Fe/H] value for the solar chemical composition (Grevesse et al 1996).…”

Section: Pulsation Amplitudesmentioning

confidence: 99%

Observational studies of Cepheid amplitudes

Klagyivik

Szabados

2009

A&A

View full text Add to dashboard Cite

Context. The dependence of amplitude on the pulsation period differs from other Cepheid-related relationships. Aims. We attempt to revise the period-amplitude (P-A) relationship of Galactic Cepheids based on multi-colour photometric and radial velocity data. Reliable P-A graphs for Galactic Cepheids constructed for the U, B, V, R C , and I C photometric bands and pulsational radial velocity variations facilitate investigations of previously poorly studied interrelations between observable amplitudes. The effects of both binarity and metallicity on the observed amplitude, and the dichotomy between short-and long-period Cepheids can both be studied. Methods. A homogeneous data set was created that contains basic physical and phenomenological properties of 369 Galactic Cepheids. Pulsation periods were revised and amplitudes were determined by the Fourier method. P-A graphs were constructed and an upper envelope to the data points was determined in each graph. Correlations between various amplitudes and amplitude-related parameters were searched for, using Cepheids without known companions. Results. Large amplitude Cepheids with companions exhibit smaller photometric amplitudes on average than solitary ones, as expected, while s-Cepheids pulsate with an arbitrary (although small) amplitude. The ratio of the observed radial velocity to blue photometric amplitudes, A V RAD /A B , is not as good an indicator of the pulsation mode as predicted theoretically. This may be caused by an incorrect mode assignment to a number of small amplitude Cepheids, which are not necessarily first overtone pulsators. The dependence of the pulsation amplitudes on wavelength is used to identify duplicity of Cepheids. More than twenty stars previously classified as solitary Cepheids are now suspected to have a companion. The ratio of photometric amplitudes observed in various bands confirms the existence of a dichotomy among normal amplitude Cepheids. The limiting period separating short-and long-period Cepheids is 10.47 days. Conclusions. Interdependences of pulsational amplitudes, the period dependence of the amplitude parameters, and the dichotomy have to be taken into account as constraints in modelling the structure and pulsation of Cepheids. Studies of the P-L relationship must comply with the break at 10. d 47 instead of the currently used "convenient" value of 10 days.

show abstract

“…It is broadly agreed that the metallicity decreases as the galactocentric radius increases in many galaxies (so-called metallicity gradient, e.g., Shields & Searle 1978;Zaritsky et al 1994), while slope of the gradient may vary within a galaxy (e.g., Luck et al 2003;Bresolin et al 2009;Balser et al 2011;Esteban et al 2013), and a significant scatter of metallicity around the gradient may also exist (e.g., Afflerbach et al 1997;Rosolowsky & Simon 2008). Some recent studies intensely performed integral field spectroscopic (IFS) observations of nearby late type galaxies (e.g., Rosales-Ortega et al 2010;Mármol-Queraltó et al 2011;Sánchez et al 2012;Fogarty et al 2012;Blanc et al 2013;Richards et al 2014;Belfiore et al 2014), and dramatically increased the sample size of HIIRs with measured metallicities.…”

Section: Introductionmentioning

confidence: 99%

Metallicity measurements of gamma-ray burst and supernova explosion sites: lessons from H ii regions in M31

Niino

Nagamine

Zhang

2015

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We examine how the small-scale (< kpc) variation of metallicity within a galaxy, which is found in nearby galaxies, affect the observational estimates of metallicity in the explosion sites of transient events such as core-collapse supernovae (CC SNe) and gamma-ray bursts (GRBs). Assuming the same luminosity, metallicity, and spatial distributions of H ii regions (hereafter HIIRs) as observed in M31, we compute the apparent metallicities that we would obtain when the spectrum of a target region is blended with those of surrounding HIIRs within the length scale of typical spatial resolution. When the spatial resolution of spectroscopy is ∼ < 0.5 kpc, which is typical for the existing studies of CC SN sites, we find that the apparent metallicities reflect the metallicities of target regions, but with significant systematic uncertainties in some cases. When the spatial resolution is ∼ > 1.0 kpc, regardless of the target regions (which has a wide range of metallicity that spans ∼ 0.6 dex for the M31 HIIRs), we always obtain the apparent metallicities similar to the average metallicity of the M31 HIIRs. Given that the apparent metallicities measured with ∼ > kpc scale resolution do not necessarily reflect the immediate environment of the stellar explosions, the current observational estimates of high metallicities for some of the long GRB host galaxies do not rule out the hypothesis that the long GRBs are exclusively born in a low-metallicity environment.

show abstract

The galactic abundance gradient from Cepheids

Cited by 132 publications

References 15 publications

The origin of carbon: Low-mass stars and an evolving, initially top-heavy IMF?

The origin of carbon: Low-mass stars and an evolving, initially top-heavy IMF?

Observational studies of Cepheid amplitudes

Metallicity measurements of gamma-ray burst and supernova explosion sites: lessons from H ii regions in M31

Contact Info

Product

Resources

About