We report the first look at extragalactic Cepheid variables with the James Webb Space Telescope, obtained from a serendipitous (to this purpose) observation of NGC 1365, host of an SN Ia (SN 2012fr), a calibration path used to measure the Hubble constant. As expected, the high-resolution observations with NIRCam through F200W show better source separation from line-of-sight companions than HST images at similar near-infrared wavelengths, the spectral region that has been used to mitigate the impact of host dust on distance measurements. Using the standard star P330E as a zeropoint and PSF reference, we photometered 31 previously-known Cepheids in the JWST field, spanning 1.15 < log P < 1.75 including 24 Cepheids in the longer period interval of 1.35 < log P < 1.75. We compared the resultant Period-Luminosity relations to that of 49 Cepheids in the full period range including 38 in the longer period range observed with WFC3/IR on HST and transformed to the JWST photometric system (F200W, Vega). The P-L relations measured with the two space telescopes are in good agreement, with intercepts (at log P=1) of 25.74+/-0.04 and 25.72+\-0.05 for HST and JWST, respectively. Our baseline result comes from the longer period range where the Cepheids have higher signal-to-noise ratios where we find 25.75+\-0.05 and 25.75+\-0.06 mag for HST and JWST, respectively. We find good consistency between this first JWST measurement and HST, and no evidence that HST Cepheid photometry is "biased bright" at the ~0.2 mag level that would be needed to mitigate the Hubble Tension, though comparisons from more SN hosts are warranted and anticipated. We expect future JWST observations to surpass these in quality as they will be optimized for measuring Cepheids.
Classical Cepheids in the JWST and Roman Era: A New Theoretical Framework and its Metallicity Dependence
INAF – Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；Istituto Nazionale di Fisica Nucleare (INFN) – Sezione di Napoli（意大利国家核物理研究院那不勒斯分部）；European Southern Observatory（欧洲南方天文台）；Scuola Superiore Meridionale（南部高等学院）
Hedorah, the first yellow supergiant Kaiju star candidate at $z=3.7$ revealed by JWST behind AS1063
Instituto de Física de Cantabria (CSIC-UC)（坎塔布里亚物理研究所）；School of Physics and Astronomy, University of Minnesota（明尼苏达大学物理与天文学院）；STAR Institute（STAR研究所）；Université Claude Bernard Lyon 1（里昂第一大学）；Department of Astronomy, University of Michigan（密歇根大学天文学系）；Department of Physics and Astronomy, University of Pennsylvania（宾夕法尼亚大学物理与天文学系）
Using a data-driven machine learning tool we report $T_{\text{eff}}$, $\log{(g)}$, $v\sin{(i)}$, and elemental abundances for 15 elements (C, N, O, Na, Mg, Al, Si, Ca, Ti, V, Cr, Mn, Fe, Ni, Y) for a sample of 25 exoplanet host stars targeted by JWST's first year of observations. The chemical diversity of these stars show that, while a number of their companion planets may have formed in a disk with chemistry similar to Solar, some JWST targets likely experienced different disk compositions. This sample is part of a larger forthcoming catalog that will report homogeneous abundances of $\sim$4,…
The MUSCLES Extension for Atmospheric Transmission Spectroscopy: Spectral energy distributions for 20 exoplanet host stars that JWST observed in Cycle 1
University of Colorado（科罗拉多大学）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；Vanderbilt University（范德堡大学）；Hamburger Sternwarte（汉堡天文台）；University of Texas, Austin（德克萨斯大学奥斯汀分校）；Southwest Research Institute（西南研究院）
Messier 15 (NGC 7078) is an old and metal-poor post core-collapse globular cluster which hosts a rich population of variable stars. We report new optical ($gi$) and near-infrared (NIR, $JK_s$) multi-epoch observations for 129 RR Lyrae, 4 Population II Cepheids (3 BL Herculis, 1 W Virginis), and 1 anomalous Cepheid variable candidate in M15 obtained using the MegaCam and the WIRCam instruments on the 3.6-m Canada-France-Hawaii Telescope. Multi-band data are used to improve the periods and classification of variable stars, and determine accurate mean magnitudes and pulsational amplitudes from th…
A Pixel-by-Pixel Path to Population III Discovery with JWST
Instituto de Astrofísica de Canarias (IAC)（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）；University of Manchester（曼彻斯特大学）；Kavli Institute for Cosmology（卡弗里宇宙学研究所）；Institute of Astronomy（天文研究所）；University of California, Santa Cruz（加州大学圣克鲁兹分校）；University of Oxford（牛津大学）；Sorbonne Université（索邦大学）；Institut d’Astrophysique de Paris（巴黎天体物理研究所）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）
A Uniform Census of Variable Stars in M101 Based on HST/ACS Photometry
CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台光学天文重点实验室）；School of Astronomy and Space Science, University of the Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学天文与前沿科学研究中心）
The VMC Survey. VIII. First results for Anomalous Cepheids
麦哲伦星云系统的VISTA近红外$YJK_\mathrm{s}$巡天（VMC，PI M. - R. L. Cioni）正在收集由两个麦哲伦云和连接它们的桥形成的系统中的脉动变星的深$K_\mathrm{s}$波段时间序列测光。在本文中，我们提出了第一次$K_\mathrm{s}$波段光变曲线的异常造父变星（AC）。特别是，我们分析了48个大麦云云AC的样本，其识别和光学星等从OGLE III和IV目录中获得。的VMC $K_\mathrm{s}$波段光变曲线的AC采样良好，与时代的数量范围从8到16，并允许我们获得非常精确的平均$K_\mathrm{s}$幅度的平均误差的顺序为0.01马格。的$\langle K_\mathrm{s} \rangle$值被用来建立第一周期亮度和周期Wesenchmann关系在近红外的基本模式和第一泛频AC。同时，我们利用光学（$V,I$）OGLE数据建立了基模和一阶泛音AC的精确周期-亮度、周期-亮度-颜色和周期-韦森关系。第一次，这些关系是来自一个样本的均匀覆盖整个AC不稳定带的振荡器。应用光学周期Wesenlavian关系的样本矮星系托管的AC显着的人口显示，这种关系是一个有价值的工具，用于推导距离内的本地集团。由于其较低的色散，我们预计$K_\mathrm{s}$周期，Wesenchmann关系首先在本文中推导出代表一个有价值的工具，用于测量…
Late-time JWST/NIRCam Observations of the Extremely Long-duration GRB 250702B/EP 250702a and Its Host Galaxy
Rutgers, the State University of New Jersey（新泽西州立罗格斯大学）；University of California, Berkeley（加州大学伯克利分校）；Berkeley Center for Multi-messenger Research on Astrophysical Transients and Outreach (Multi-RAPTOR), University of California, Berkeley（加州大学伯克利分校多信使天体物理瞬变现象与外展研究中心（Multi-RAPTOR））；University of Utah（犹他大学）；Radboud University（拉德堡德大学）；University of Warwick（华威大学）
