The redshift range z=4-6 marks a transition phase between primordial and mature galaxy formation in which galaxies considerably increase their stellar mass, metallicity, and dust content. The study of galaxies in this redshift range is therefore important to understand early galaxy formation and the fate of galaxies at later times. Here, we investigate the burstiness of the recent star-formation history (SFH) of 221 $z\sim4.5$ main-sequence galaxies at log(M) > 9.7 by comparing their ultra-violet (UV) continuum, H$α$ luminosity, and H$α$ equivalent-width (EW). The H$α$ properties are derived from the Spitzer [3.6$μ$m]-[4.5$μ$m] broad-band color, thereby properly taking into account model and photometric uncertainties. We find a significant scatter between H$α$ and UV-derived luminosities and star-formation rates (SFRs). About half of the galaxies show a significant excess in H$α$ compared to expectations from a constant smooth SFH. We also find a tentative anti-correlation between H$α$ EW and stellar mass, ranging from 1000$Å$ at log(M) < 10 to below 100$Å$ at log(M) > 11. Consulting models suggests that most $z\sim4.5$ galaxies had a burst of star-formation within the last 50 Myrs, increasing their SFRs by a factor of > 5. The most massive galaxies on the other hand might decrease their SFRs, and may be transitioning to a quiescent stage by z=4. We identify differential dust attenuation (f) between stars and nebular regions as the main contributor to the uncertainty. With local galaxies selected by increasing H$α$ EW (reaching values similar to high-z galaxies), we predict that f approaches unity at $z>4$ consistent with the extrapolation of measurements out to z=2.
The Physical Conditions of Low-Mass Galaxies at z=3.5-7.0 from JWST Spectroscopy: The Behaviour of Spectral Line Ratios with Burstiness
University of Groningen（格罗宁根大学）；Università degli Studi di Firenze（佛罗伦萨大学）；INAF – Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切特里天文台）；Institute of Science and Technology Austria (ISTA)（奥地利科学与技术研究院）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；University of Chicago（芝加哥大学）
Relatively Fast and Reasonably Furious: Evidence for Increased Burstiness in Smaller Halos at Cosmic Dawn
The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Northwestern University（西北大学）；California Institute of Technology（加州理工学院）；Jet Propulsion Laboratory（喷气推进实验室）
Beyond Extreme Burstiness: Evolving Star Formation Efficiency as the Key to Early Galaxy Abundance
Indian Institute of Science Education and Research Berhampur（印度科学教育与研究学院伯赫姆普尔分校）；Tata Institute of Fundamental Research（塔塔基础研究所）；The Johns Hopkins University（约翰斯·霍普金斯大学）
Inferred Hα Flux as a Star-Formation Rate Indicator at z ~ 4-5: Implications for Dust Properties, Burstiness, and the z = 4-8 Star-Formation-Rate Functions
The Impact of Star Formation Histories on the Inner Dark Matter Density Slopes of Galaxies
Instituto de Astrofísica de Canarias (IAC)（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Department of Physics & Astronomy, University of Southern California（南加州大学物理与天文系）；New York University Abu Dhabi（阿布扎比纽约大学）；Center for Astrophysics and Space Science, New York University Abu Dhabi（阿布扎比纽约大学天体物理学与空间科学中心）
Stochastic star formation activity of galaxies within the first billion years probed by JWST
Aix Marseille Univ, CNRS, CNES, LAM（艾克斯-马赛大学）；Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange（蔚蓝海岸大学，蔚蓝海岸天文台）；Institut d’Astrophysique de Paris, UMR 7095, CNRS, Sorbonne Université（巴黎天体物理研究所，索邦大学）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Department of Astronomy, University of Geneva（日内瓦大学天文学系）
NIRSpec View of the Appearance and Evolution of Balmer Breaks and the Transition from Bursty to Smooth Star Formation Histories from Deep Within the Epoch of Reionization to Cosmic Noon
The THESAN-ZOOM project: Burst, quench, repeat -- unveiling the evolution of high-redshift galaxies along the star-forming main sequence
Kavli Institute for Cosmology, University of Cambridge（卡弗里宇宙学研究所，剑桥大学）；Cavendish Laboratory, University of Cambridge（卡文迪许实验室，剑桥大学）；Department of Physics, The University of Texas at Dallas（德克萨斯大学达拉斯分校物理系）；Department of Physics and Astronomy, York University（约克大学物理与天文系）；Leibniz-Institut für Astrophysik Potsdam（波茨坦阿斯特拉诺伊克莱布尼茨研究所）；Department of Physics and Astronomy, University of Pennsylvania（宾夕法尼亚大学物理与天文系）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学 Kavli 宇宙物理学与数学起源联合研究中心（WPI），UTIAS）；Institute for Fundamental Physics of the Universe（宇宙基本物理研究所）；Institute for Astronomy, University of Edinburgh（爱丁堡大学天文学研究所）
Bright Galaxies at Cosmic Dawn: A Cloud-Scale Star Formation Model Unifying Variable SFE, IMFs, and Stochasticity
Max Planck Institut für Astrophysik（马克斯·普朗克天体物理学研究所）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Department of Astrophysics, University of Vienna（维也纳大学天体物理系）
It's More Complicated Than You Think: A Forward Model to Infer the Recent Star Formation History, Bursty or Not, of Galaxy Populations
The Pennsylvania State University（宾夕法尼亚州立大学）；Princeton University（普林斯顿大学）；Wesleyan University（卫斯理安大学）；Columbia University（哥伦比亚大学）；Flatiron Institute（平井研究所）
When galaxies burst: enhanced shot-noise for line-intensity mapping in the JWST era
Ben-Gurion University of the Negev（内盖夫本-古里安大学）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Cosmic Frontier Center, The University of Texas at Austin（德克萨斯大学奥斯汀分校宇宙前沿中心）；Tel-Aviv University（特拉维夫大学）
UNCOVER/MegaScience Finds Uniform and Highly Bursty Star Formation at 3 < z < 9, consistent with the High-Redshift UV Luminosity Function
University of Colorado, Boulder（科罗拉多大学博尔德分校）；The Pennsylvania State University（宾夕法尼亚州立大学）；University of Pittsburgh（匹兹堡大学）；Princeton University（普林斯顿大学）；University of Washington（华盛顿大学）；Swinburne University of Technology（斯威本科技大学）；Space Telescope Science Institute (STScI)（太空望远镜科学研究所）；MIT Kavli Institute for Astrophysics and Space Research（麻省理工学院卡弗里天体物理与空间研究所）；Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡普坦天文研究所）；University of Toronto（多伦多大学）；University of Zurich（苏黎世大学）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Ben-Gurion University of the Negev（内盖夫本-古里安大学）；University of California, Berkeley（加州大学伯克利分校）；Cosmic Dawn Center (DAWN), Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所宇宙黎明中心（DAWN））；University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）；Tufts University（塔夫茨大学）
UNCOVER/MegaScience 发现 3 < z < 9 范围内恒星形成具有均匀且高度爆发性，与高红移紫外光度函数一致。
