The Cepheid distance to the Large Magellanic Cloud and NGC 4258 by the surface brightness technique and improved calibration of the cosmic distance scale
The Cepheid distance to the Large Magellanic Cloud and NGC 4258 by the surface brightness technique and improved calibration of the cosmic distance scale
复制标题
通过表面亮度技术和改进的宇宙距离标度校准计算造父变星到大麦哲伦星云和 NGC 4258 的距离
DOI：
10.1111/j.1365-2966.2008.13884.x
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发表时间：
2008
影响因子：
4.8
通讯作者：
G. Benedetto
中科院分区：
文献类型：
--
作者：
G. Benedetto
我报告的实施的表面亮度（SB）的技术，旨在获得可靠的造父变星的角直径在光学波长，然后巴德-韦塞林克（BW）的距离使用光谱线半径。该技术被应用于校准的银河系距离尺度和大麦哲伦云（LMC）的距离的基础上，该银河系校准。LMC距离得益于大量造父变星的高精度测光和红化数据，这些数据可由Udalski等人的光学引力透镜实验获得，并得益于改进和改进，包括（i）对各个距离的最小二乘（LS）拟合方法，以恢复不受目标造父变星的周期分布偏置的距离模量，以及（ii）更好地理解金属丰度对周期光度关系和SB尺度的影响。由此得到的LMC的真实距离模为μ 0（LMC）= [18.559 ± 0.003（随机）± 0.026（系统）] ma. SB技术也被应用于确定造父变星到脉泽宿主星系NGC 4258的距离.在近太阳金属丰度的内区造父变星产生的真实距离模数为μ 0（NGC 4258）= [29.28 ± 0.03（随机）± 0.03（系统）] mag，在0.01 mag水平上与高权重几何水脉泽距离模数非常吻合。结果表明，目前的数据减少平均个人造父变星距离的方法可以引入显着的系统误差的距离尺度校准。从哈勃空间望远镜（HST）上的一个小样本中，我们得到了（12 ± 5）%的总误差，这意味着在其它条件相同的情况下，Freedman等人的哈勃常数被向下修正为H 0 =（63 ± 7）km s-1 Mpc-1。
I report on the implementation of the surface brightness (SB) technique aimed at deriving reliable Cepheid angular diameters at optical wavelengths and then Baade-Wesselink (BW) distances using spectroscopic linear radii. The technique is applied to calibrate the Galactic distance scale and the distance to the Large Magellanic Cloud (LMC) based on this Galactic calibration. The LMC distance benefits from the large number of Cepheids with high-precision photometry and reddening data available by the Optical Gravitational Lensing Experiment of Udalski et al. and from improvements and refinements, including (i) a least-squares (LS) fitting approach to the individual distances to recover the distance modulus unbiased by the period distribution of target Cepheids and (ii) a better understanding of the metallicity effects on the period-luminosity relations and SB scales. The resulting true distance modulus of the LMC is μ 0 (LMC) = [18.559 ± 0.003 (random) ± 0.026 (systematic)] mag. The SB technique is also applied to confidently determine the Cepheid distance to the maser host galaxy NGC 4258. Cepheids in the inner region with near solar metallicity yield a true distance modulus of μ 0 (NGC 4258) = [29.28 ± 0.03 (random) ± 0.03 (systematic)] mag, in excellent agreement, at the 0.01 mag level, with the high-weight geometric water maser distance modulus. It is shown that the current data-reduction approach of averaging individual Cepheid distances can introduce significant systematic errors in the distance scale calibration. From a small sample of Hubble Space Telescope (HST) based galaxies, I derive an overall error of (12 ± 5) per cent, which would suggest a downward revision of the Freedman et al. Hubble constant to the value H 0 = (63 ± 7) km s -1 Mpc -1 , other things being equal.