Metal abundances of RR Lyrae stars in the bar of the Large Magellanic Cloud

Gratton, R.; Bragaglia, A.; Clementini, G.; Carretta, E.; Fabrizio, L. Di; Maio, M.; Taribello, E.

doi:10.1051/0004-6361:20035840

Cited by 124 publications

(244 citation statements)

References 43 publications

(94 reference statements)

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“…We decided to evaluate the relations for α=1.5±0.5 (to encompass reasonable values for α) and [Fe/H]=−1.5±0.3 dex as an average value for the LMC old population (see, e.g. Borissova et al 2004Borissova et al , 2006Gratton et al 2004;Haschke et al 2012). The uncertainties on these parameters were taken into account in re-deriving the ZP of the predicted P L and P W relations in the VISTA system.…”

Section: Comparison With the Literaturementioning

confidence: 99%

The VMC Survey – XIII. Type II Cepheids in the Large Magellanic Cloud★

Ripepi

Moretti

Marconi

et al. 2014

Monthly Notices of the Royal Astronomical Society

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The VISTA survey of the Magellanic Clouds System (VMC) is collecting deep K s -band time-series photometry of the pulsating variable stars hosted in the system formed by the two Magellanic Clouds and the Bridge connecting them. In this paper we have analysed a sample of 130 Large Magellanic Cloud (LMC) Type II Cepheids (T2CEPs) found in tiles with complete or near complete VMC observations for which identification and optical magnitudes were obtained from the OGLE III survey. We present J and K s light curves for all 130 pulsators, including 41 BL Her, 62 W Vir (12 pW Vir) and 27 RV Tau variables. We complement our near-infrared photometry with the V magnitudes from the OGLE III survey, allowing us to build a variety of PeriodLuminosity (P L), Period-Luminosity-Colour (P LC) and Period-Wesenheit (P W ) relationships, including any combination of the V, J, K s filters and valid for BL Her and W Vir classes. These relationships were calibrated in terms of the LMC distance modulus, while an independent absolute calibration of the P L(K s ) and the P W (K s , V ) was derived on the basis of distances obtained from Hubble Space T elescope parallaxes and Baade-Wesselink technique. When applied to the LMC and to the Galactic Globular Clusters hosting T2CEPs, these relations seem to show that: 1) the two population II standard candles RR Lyrae and T2CEPs give results in excellent agreement with each other; 2) there is a discrepancy of ∼0.1 mag between population II standard candles and Classical Cepheids when the distances are gauged in a similar way for all the quoted pulsators. However, given the uncertainties, this discrepancy is within the formal 1σ uncertainties.

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Section: Comparison With the Literaturementioning

confidence: 99%

The VMC Survey – XIII. Type II Cepheids in the Large Magellanic Cloud★

Ripepi

Moretti

Marconi

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…They are measured from good quality low-resolution spectra obtained with FORS1, FORS2, and GEMINI-GMOS, using Gratton et al (2004) calibration on the Harris (1996) metallicity scale (see Paper II for more details).…”

Section: Mean J and K S Magnitudes And Error Analysismentioning

confidence: 99%

Properties of RR Lyrae stars in the inner regions of the Large Magellanic Cloud

Borissova¹,

Rejkuba²,

Minniti

et al. 2009

A&A

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Context. RR Lyrae variable stars are the primary Population II distance indicator. Likewise, the Large Magellanic Cloud (LMC) constitutes a key step in the extragalactic distance scale. Aims. By combining near-IR photometry and spectroscopically measured metallicities for a homogeneous sample of 50 RR Lyr stars in the LMC, we investigate the metallicity dependence of the period-luminosity relation in the near-infrared (IR), use the newly derived relations to re-derive the distance to the LMC, and compare the distance moduli obtained from RR Lyr and red clump stars. Methods. This paper presents new (single-epoch) J-band and (multi-epoch) K s -band photometry of RR Lyr stars in 7 different LMC fields, observed with the near-IR camera SOFI at ESO's New Technology Telescope. Additional K s -band data for another two LMC fields were taken with the ISPI infrared array at CTIO's Blanco 4m telescope. The near-IR photometry was cross-correlated with the MACHO and OGLE databases, resulting in a catalog of 62 RR Lyr stars with BVRI JK s photometry. A subsample of 50 stars also has spectroscopically measured metallicities. Results. In the deep JK color-magnitude diagrams of 7 fields, red giant branch, red clump and RR Lyr stars are detected. The majority of RR Lyr stars are located within the instability strip with near-IR colors between 0.14 ≤ (J − K s ) 0 < 0.32. The period-luminosity relation only has a very mild dependence on metallicity in the K band, consistent with no dependence: M Ks = 2.11(±0.17) log P + 0.05(±0.07) [Fe/H] − 1.05. In the J band the currently available data do not allow firm conclusions regarding the metallicity dependence of the period-luminosity relation. Conclusions. The distance modulus of the LMC, derived using our near-IR period-luminosity-metallicity relation for RR Lyr stars, is (m − M) 0 = 18.53 ± 0.13, in very good agreement with the distance modulus from the red clump stars, 18.46 ± 0.07. However, LMC modulus derived from the RR Lyrae stars depends on the parallax of the star RR Lyrae.

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“…Spectroscopic data of about 250 LMC RR Lyrae were obtained by Gratton et al (2004), and Borissova et al (2004Borissova et al ( , 2006. They were used to estimate the metal abundance, radial velocity and radial velocity dispersion of the LMC RR Lyrae population.…”

Section: The Mcs Rr Lyrae Starsmentioning

confidence: 99%

“…The radial velocity dispersion, σ vr = 50 km s −1 , does not vary significantly with increasing distance from the LMC center (Borissova et al 2006 and references therein), and is higher than the velocity dispersion of any other LMC population previously measured, thus providing empirical evidence for a kinematically hot, metal-poor halo in the LMC. Gratton et al (2004) combined their spectroscopic measurements with high accuracy V magnitudes for about a hundred RR Lyrae stars by Clementini et al (2003) to derive the luminosity-metallicity relation of the LMC variables, for which they found the following linear relation: M V = 0.214 ([Fe/H] + 1.5) + 19.064. The slope of this relation agrees very well with slopes derived for the luminositymetallicity relation of the MW RR Lyrae stars (Fernley et al 1998) and horizontal branch stars in the globular clusters of M 31 (Rich et al 2005), thus supporting the idea that the luminosity-metallicity relation of the RR Lyrae stars is, in first approximation, linear and universal.…”

Section: The Mcs Rr Lyrae Starsmentioning

confidence: 99%

Pulsating variable stars in the Magellanic Clouds

Clementini

2008

Proc. IAU

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Abstract. Pulsating variable stars can be powerful tools to study the structure, formation and evolution of galaxies. I discuss the role that the Magellanic Clouds' pulsating variables play in our understanding of the whole Magellanic System, in light of results on pulsating variables produced by extensive observing campaigns like the MACHO and OGLE microlensing surveys. In this context, I also briefly outline the promise of new surveys and astrometric missions which will target the Clouds in the near future.

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Metal abundances of RR Lyrae stars in the bar of the Large Magellanic Cloud

Cited by 124 publications

References 43 publications

The VMC Survey – XIII. Type II Cepheids in the Large Magellanic Cloud★

The VMC Survey – XIII. Type II Cepheids in the Large Magellanic Cloud★

Properties of RR Lyrae stars in the inner regions of the Large Magellanic Cloud

Pulsating variable stars in the Magellanic Clouds

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