The near-IR surface brightness method applied to six Cepheids in the young LMC cluster NGC 1866

Storm, J.; Gieren, W.; Fouqué, P.; Barnes, Thomas G.; Gómez, M.

doi:10.1051/0004-6361:20053067

Cited by 21 publications

(60 citation statements)

References 41 publications

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“…As for the near-infrared K band, we used the data set described in Storm et al (2005) and Testa et al (2007). Furthermore, we used unpublished data collected by J.…”

Section: Photometrymentioning

confidence: 99%

“…The data from Testa et al (2007) were calibrated in the LCO photometric system using the relations from Carpenter (2001). K-band data from Storm et al (2005) were calibrated in the CIT photometric system.…”

Section: Photometrymentioning

confidence: 99%

“…We used the radial velocity data from Storm et al (2005Storm et al ( , 2004) and Welch et al (1991), obtained through the classical crosscorrelation method. For three Cepheids, namely HV 12197, HV 12199, and We2, we used new data coming from the VLT/FLAMES data set by Mucciarelli et al (2011;Appendix A).…”

Section: Radial Velocitymentioning

confidence: 99%

“…A strong drawback to this procedure is the role played by metallicity in the period-luminosity relation. From both the observational and theoretical perspective, some authors argue that this dependence is present (e.g., Freedman et al 2001;Storm et al 2003;Tammann et al 2003;Sakai et al 2004;Romaniello et al 2005;Macri et al 2006;Bono et al 2008Bono et al , 2010 even if the size and the sign of the effect are still disputed, while others suggest that the effect is small and perhaps ill defined (e.g., Groenewegen & Salaris 2003;Gieren et al 2005;Storm et al 2005Storm et al , 2011bAlibert et al 1999).…”

Section: Introductionmentioning

confidence: 99%

“…This object is one of the few young (∼10 8 yr; Brocato et al 1989) LMC clusters that are close enough to allow for detailed observation of individual stars (see, e.g., Mucciarelli et al 2011;Brocato et al 2003, and references therein). Moreover, Storm et al (2005) found that the NGC 1866 Cepheids are close to the average LMC Cepheid distance, so we will assume the distance to this cluster to be the distance of the LMC itself. To date, it is known that NGC 1866 harbors at least 23 Cepheids (Welch & Stetson 1993;Musella et al 2006), the largest number among all the LMC clusters, and this makes it an excellent system for distance determination.…”

Section: Introductionmentioning

confidence: 99%

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Cors Baade–wesselink Distance to the LMC NGC 1866 Blue Populous Cluster

Molinaro¹,

Ripepi²,

Marconi³

et al. 2012

ApJ

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We used optical, near-infrared photometry, and radial velocity data for a sample of 11 Cepheids belonging to the young LMC blue populous cluster NGC 1866 to estimate their radii and distances on the basis of the CORS Baade-Wesselink method. This technique, based on an accurate calibration of surface brightness as a function of (U − B), (V − K) colors, allows us to estimate, simultaneously, the linear radius and the angular diameter of Cepheid variables, and consequently to derive their distance. A rigorous error estimate on radii and distances was derived by using Monte Carlo simulations. Our analysis gives a distance modulus for NGC 1866 of 18.51 ± 0.03 mag, which is in agreement with several independent results.

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“…As for the near-infrared K band, we used the data set described in Storm et al (2005) and Testa et al (2007). Furthermore, we used unpublished data collected by J.…”

Section: Photometrymentioning

confidence: 99%

Section: Photometrymentioning

confidence: 99%

Section: Radial Velocitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Cors Baade–wesselink Distance to the LMC NGC 1866 Blue Populous Cluster

Molinaro¹,

Ripepi²,

Marconi³

et al. 2012

ApJ

Self Cite

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Calibrating the Cepheid period-luminosity relation from the infrared surface brightness technique

Storm

Gieren

Fouqué

et al. 2011

A&A

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109

111

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Context. The extragalactic distance scale builds directly on the Cepheid period-luminosity (PL) relation as delineated by the sample of Cepheids in the Large Magellanic Cloud (LMC). However, the LMC is a dwarf irregular galaxy, quite different from the massive spiral galaxies used for calibrating the extragalactic distance scale. Recent investigations suggest that not only the zero-point but also the slope of the Milky Way PL relation differ significantly from that of the LMC, casting doubts on the universality of the Cepheid PL relation. Aims. We want to make a differential comparison of the PL relations in the two galaxies by delineating the PL relations using the same method, the infrared surface brightness method (IRSB), and the same precepts. We furthermore extend the metallicity baseline for investigating the zero-point dependence, by applying the method to five SMC Cepheids as well. Methods. The IRSB method is a Baade-Wesselink type method to determine individual distances to Cepheids. We apply a newly revised calibration of the method as described in an accompanying paper (Paper I) to 36 LMC and five SMC Cepheids and delineate new PL relations in the V, I, J, & K bands as well as in the Wesenheit indices in the optical and near-IR. Results. We present 509 new and accurate radial velocity measurements for a sample of 22 LMC Cepheids, enlarging our earlier sample of 14 stars to include 36 LMC Cepheids. The new calibration of the IRSB method is directly tied to the recent HST parallax measurements to ten Milky Way Cepheids, and we find a LMC barycenter distance modulus of 18.45 ± 0.04 (random error only) from the 36 individual LMC Cepheid distances. In the J, K bands we find identical slopes for the LMC and Milky Way PL relations and only a weak letallicity effect on the zero points (consistent with a zero effect), metal poor stars being fainter. In the optical we find the Milky Way slopes are slightly shallower than the LMC slopes (but again consistent with no difference in the slopes) and small effects on the zero points. However, the important Wesenheit index in V, (V − I) shows a metallicity effect on the slope and on the zero point which is likely to be significant. Conclusions. We find a significant metallicity effect on the W VI index γ(W VI ) = −0.23 ± 0.10 mag dex −1 as well as an effect on the slope. The K-band PL relation on the other hand is found to be an excellent extragalactic standard candle being metallicity insensitive in both slope and zero-point and at the same time being reddening insensitive and showing the least internal dispersion.

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Calibrating the Cepheid period-luminosity relation from the infrared surface brightness technique

Storm

Gieren

Fouqué

et al. 2011

A&A

Self Cite

145

204

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Aims. We determine period-luminosity relations for Milky Way Cepheids in the optical and near-IR bands. These relations can be used directly as reference for extra-galactic distance determination to Cepheid populations with solar metallicity, and they form the basis for a direct comparison with relations obtained in exactly the same manner for stars in the Magellanic Clouds, presented in an accompanying paper. In that paper we show that the metallicity effect is very small and consistent with a null effect, particularly in the near-IR bands, and we combine here all 111 Cepheids from the Milky Way, the LMC and SMC to form a best relation. Methods. We employ the near-IR surface brightness (IRSB) method to determine direct distances to the individual Cepheids after we have recalibrated the projection factor using the recent parallax measurements to ten Galactic Cepheids and the constraint that Cepheid distances to the LMC should be independent of pulsation period. Results. We confirm our earlier finding that the projection factor for converting radial velocity to pulsational velocity depends quite steeply on pulsation period, p = 1.550− 0.186 log(P) in disagrement with recent theoretical predictions. We find PL relations based on 70 Milky Way fundamental mode Cepheids of M K = −3.33(±0.09)(log(P) − 1.0) − 5.66(±0.03), W VI = −3.26(±0.11)(log(P) − 1.0) − 5.96(±0.04). Combining the 70 Cepheids presented here with the results for 41 Magellanic Cloud Cepheids which are presented in an accompanying paper, we find M K = −3.30(±0.06)(log(P) − 1.0) − 5.65(±0.02), W VI = −3.32(±0.08)(log(P) − 1.0) − 5.92(±0.03). Conclusions. We delineate the Cepheid PL relation using 111 Cepheids with direct distances from the IRSB analysis. The relations are by construction in agreement with the recent HST parallax distances to Cepheids and slopes are in excellent agreement with the slopes of apparent magnitudes versus period observed in the LMC.

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The near-IR surface brightness method applied to six Cepheids in the young LMC cluster NGC 1866

Cited by 21 publications

References 41 publications

Cors Baade–wesselink Distance to the LMC NGC 1866 Blue Populous Cluster

Cors Baade–wesselink Distance to the LMC NGC 1866 Blue Populous Cluster

Calibrating the Cepheid period-luminosity relation from the infrared surface brightness technique

Calibrating the Cepheid period-luminosity relation from the infrared surface brightness technique

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