Exploring the ultra-faint dwarf Bootes I using JWST and HST: Metallicity distribution and binaries
Università Degli Studi di Padova（帕多瓦大学）；Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）；Research School of Astronomy and Astrophysics, Australian National University（澳大利亚国立大学天文与天体物理研究学院）；South-Western Institute for Astronomy Research, Yunnan University（云南大学西南天文研究所）
F. Muratore, M. V. Legnardi, A. P. Milone, A. Mastrobuono-Battisti, G. Cordoni, L. N. Gorza, E. P. Lagioia, E. Bortolan, E. Dondoglio, A. F. Marino, T. Ziliotto
备注：
11 pages, 10 figures, Accepted for publication in Astronomy & Astrophysics
Ultra-faint dwarf galaxies (UFDs) are among the oldest and most metal-poor stellar systems in the Universe. Their metallicity distribution encodes the fossil record of the earliest star formation, feedback, and chemical enrichment, providing crucial tests of models of the first stars, galaxy assembly, and dark matter halos. However, due to their faint luminosities and the limited number of bright giants, spectroscopic studies of UFDs typically probe only small stellar samples. Here, we present an analysis of multi-epoch Hubble Space Telescope and James Webb Space Telescope observations of the UFD Bootes I. Using deep color-magnitude diagram in the F606W and F322W2 bands, extending from the subgiant branch to the M-dwarfs, and stellar proper motions to identify likely members, we obtained an unprecedentedly clean census of the system. The exquisite quality of the diagram, combined with the sensitivity of M-dwarf colors to metallicity, allowed us to constrain the metallicity distribution in a large stellar sample. As a first step, we derived the binary fraction in Bootes I. This is crucial, since binaries can bias kinematic mass estimates, affect stellar population analyses, and shape the photometric signatures used to infer metallicity. We find that 20$\pm$2% of stellar systems in Bootes I are binaries with mass ratios larger than 0.4, corresponding to a total binary fraction of $\sim$30%. This value is comparable to the binary fractions observed in globular clusters of similar stellar mass, suggesting that the presence of dark matter does not significantly affect the binary properties of Bootes I. We then exploited the metallicity sensitivity of M-dwarf colors to derive the metallicity distribution function. We find that most of the stars $\sim$85% have [Fe/H]<-2, and that roughly $\sim$17% have [Fe/H]<-3.
Probing the IMF in the Early Universe -- Direct measurements in the Boötes I UFD with JWST/NIRCam
University of Maryland, College Park（马里兰大学帕克分校）；Space Telescope Science Institute（太空望远镜科学研究所）；INAF – Osservatorio Astronomico di Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）；INFN – Sezione di Pisa, Universita’ di Pisa（意大利国家核物理研究所比萨分部，比萨大学）
通过JWST/NIRCam对Boötes I UFD中低质量IMF进行研究，结合机器学习和统计方法，发现单幂律IMF无法再现观测到的光度函数，而分段幂律和对数正态IMF参数与银河系一致，表明低金属度下恒星形成遵循相似IMF。
The JWST Resolved Stellar Populations Early Release Science Program. IX. The RR Lyrae Population in WLM with HST and JWST
Minnesota Institute for Astrophysics, University of Minnesota（明尼苏达大学天体物理研究所）；Department of Astronomy, University of California, Berkeley（加州大学伯克利分校天文学系）；Space Telescope Science Institute（太空望远镜科学研究所）；Department of Physics and Astronomy, Rutgers, the State University of New Jersey（新泽西州立大学罗格斯大学物理与天文系）
Tracing the earliest stages of star and cluster formation in 19 nearby galaxies with PHANGS-JWST and HST: compact 3.3 $μ$m PAH emitters and their relation to the optical census of star clusters
University of Minnesota（明尼苏达大学）；Northwestern University（西北大学）；University of California, Berkeley（加州大学伯克利分校）；University of Washington（华盛顿大学）；Raytheon（雷神公司）；University of Arizona（亚利桑那大学）；Rutgers, the State University of New Jersey（新泽西州立罗格斯大学）；Space Telescope Science Institute（太空望远镜科学研究所）
Multi-wavelength morphology and dust emission in low-redshift dwarf galaxies in COSMOS-Web with HST and JWST
University of Hertfordshire（赫特福德大学）；Rochester Institute of Technology（罗切斯特理工学院）；University of Manchester（曼彻斯特大学）；University of Nottingham（诺丁汉大学）；University of Cambridge（剑桥大学）
Evolution and Mass Dependence of UV-to-near-IR Color Gradients up to z=2.5 from HST+JWST
Universiteit Gent（根特大学）；University of Michigan（密歇根大学）；University of Copenhagen（哥本哈根大学）；Université de Liège（列日大学）；University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）；University of Bath（巴斯大学）
A joint JWST and HST view of Omega Centauri: Multiple stellar populations and their kinematics
Univ. di Padova（帕多瓦大学）；Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Padova（意大利国家天体物理研究所-帕多瓦天文台）；Research School of Astronomy & Astrophysics, Australian National University（澳大利亚国立大学天文与天体物理研究学院）
Witnessing the rapid growth of disk galaxies over cosmic time using JWST and HST
Universidad de Valladolid（巴利亚多利德大学）；Laboratory for Disruptive Interdisciplinary Science (LaDIS), Universidad de Valladolid（巴利亚多利德大学颠覆性跨学科科学实验室）；Institute of Space Sciences (ICE, CSIC)（空间科学研究所（ICE，CSIC））；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Departamento de Astrofísica, Universidad de La Laguna（拉帕拉塔大学天体物理学系）；Instituto de Astrofísica e Ciéncia do Espaço, Universidad de Lisboa（里斯本大学天体物理学与空间科学研究所）
Varstrometry for Off-nucleus and Dual Subkiloparsec AGN (VODKA): Three Quadruply Lensed Quasars at Cosmic Noon in HST and JWST
Johns Hopkins University（约翰斯·霍普金斯大学）；University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）；Wuhan University（武汉大学）；Institute for Advanced Study（普林斯顿高等研究院）；Massachusetts Institute of Technology（麻省理工学院）
CANUCS/Technicolor Data Release 2: A Catalogue of Galaxy Structural Parameters in up to 29 HST+JWST bands and a Multi-Wavelength Exploration of the Galaxy Size-Mass Relation at $0.6 < z \leq 4$
York University（约克大学）；Wellesley College（韦尔斯利学院）；Independent University Bangladesh（孟加拉独立大学）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；DTU-Space, Technical University of Denmark（丹麦技术大学空间科学中心）；National Research Council of Canada, Herzberg Astronomy & Astrophysics Research Centre（加拿大国家研究委员会赫茨伯格天体物理学与天文学研究中心）
Probing the earliest phases in the formation of massive galaxies with simulated HST+JWST imaging data from Illustris
我们使用的Illustris-1模拟探索的$\textit{Hubble}$和$\textit{James Webb Space Telescope}$数据的能力，分析在高红移星系的恒星种群，利用相结合的深度，空间分辨率和波长覆盖范围。为此，我们使用模拟的宽带ACS，WFC 3和NIRCam数据和2维恒星布居合成（2D-SPS）导出的综合恒星形成历史（SFH）的大质量（M $_{\ast}>10^{10}\,$ M $_{\odot}$）模拟星系在$1<z<4$演变成一个本地M $_{\ast}>10^{11}\,$ M $_{\odot}$星系。特别是，我们探索的潜力HST和JWST数据集达到的深度类似的CANDELS和正在进行的CEERS观测，分别，并集中在确定该数据集的能力，为本地M $_{\ast}>10^{11}\,$ M $_{\odot}$星系的SFH的第一集通过研究他们的祖先在$z>1$。本文提出的2D-SPS方法已经过校准，可以稳健地恢复大质量星系中第一次恒星形成事件发生的宇宙时间，即，他们的综合SFH的第一阶段。特别是，我们讨论的时间时，第一个1%至50%的总恒星质量形成的模拟。我们证明，我们可以恢复这些年龄与典型的中位数系统偏移小于5%，分散在20%-30%。根据我们对Illustris数据的测量，我们能够恢复本地M $_{\ast}>10^{11}\,$ M…
The BoRG-$JWST$ Survey: Abundance and Mass-to-light Ratio of Luminous $z=7-9$ Galaxies from Independent Sight Lines with NIRSpec
University of California, Los Angeles（加州大学洛杉矶分校）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；University of Geneva（日内瓦大学）；California Institute of Technology（加州理工学院）；National Astronomical Research Institute of Thailand (NARIT)（泰国国家天文研究所）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Max Planck Institut für Astronomie（马克斯·普朗克天体物理研究所）；University of Melbourne（墨尔本大学）
