JWST观测排除造父变星光度测量的未识别拥挤作为哈勃张力在8 sigma置信度下的解释
JWST Observations Reject Unrecognized Crowding of Cepheid Photometry as an Explanation for the Hubble Tension at 8 sigma Confidence
AI总结：
本研究利用JWST对NGC4258及5个Ia型超新星宿主星系中超1000颗造父变星进行高清观测，发现其与HST测量结果无显著差异，在8.2 sigma置信度下排除了HST光度测量拥挤误差导致哈勃张力的假设。
摘要：
我们展示了使用詹姆斯·韦伯空间望远镜（JWST）对距离阶梯几何锚点NGC4258中的>1000颗造父变星以及8颗Ia型超新星（SNe Ia）宿主星系中的5个进行的高清观测，其样本量远大于以往使用JWST的研究。这些星系各自包含最大规模的造父变星样本，平均每个星系>150颗，从而为与先前使用哈勃空间望远镜（HST）在近红外（NIR）波段测量的结果进行最强的统计比较提供了基础。它们也跨越了用于通过HST确定哈勃常数的距离范围，使我们能够寻找HST测量中与距离相关的偏差。JWST卓越的分辨率消除了拥挤噪声，这是使用HST测量的近红外造父变星周期-光度关系（Leavitt定律）中最大的方差来源。结合使用两个历元来约束造父变星相位以及使用三个滤光片来消除红化，我们将造父变星PL关系中的色散降低了2.5倍。我们发现，由HST和JWST确定的平均距离测量结果没有显著差异，形式上的差异为-0.01+/-0.03星等。该结果独立于零点及分析变体，包括金属丰度依赖性、局部拥挤、滤光片选择和关系斜率。我们可以排除HST造父变星光度测量中随距离增长的未识别拥挤是“哈勃张力”成因的假设，置信度为8.2 sigma，即比哈勃张力本身的置信度更高。我们得出结论，跨越距离阶梯的造父变星光度测量误差对哈勃张力的贡献并不显著。
英文摘要：
We present high-definition observations with the James Webb Space Telescope of >1000 Cepheids in a geometric anchor of the distance ladder, NGC4258, and in 5 hosts of 8 SNe~Ia, a far greater sample than previous studies with JWST. These galaxies individually contain the largest samples of Cepheids, an average of >150 each, producing the strongest statistical comparison to those previously measured with the Hubble Space Telescope in the NIR. They also span the distance range of those used to determine the Hubble constant with HST, allowing us to search for a distance-dependent bias in HST measurements. The superior resolution of JWST negates crowding noise, the largest source of variance in the NIR Cepheid Period-Luminosity relations (Leavitt laws) measured with HST. Together with the use of two-epochs to constrain Cepheid phases and three filters to remove reddening, we reduce the dispersion in the Cepheid PL relations by a factor of 2.5. We find no significant difference in the mean distance measurements determined from HST and JWST, with a formal difference of -0.01+/-0.03 mag. This result is independent of zeropoints and analysis variants including metallicity dependence, local crowding, choice of filters, and relation slope. We can reject the hypothesis of unrecognized crowding of Cepheid photometry from HST that grows with distance as the cause of the ``Hubble Tension'' at 8.2 sigma, i.e., greater confidence than that of the Hubble Tension itself. We conclude that errors in photometric measurements of Cepheids across the distance ladder do not significantly contribute to the Tension.
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