One of the key questions in understanding the formation and evolution of galaxies is how starbursts affect the assembly of stellar populations in galaxies over time. We define a burst indicator ($η$), which compares a galaxy's star formation rates on short ($\sim10$ Myr) and long ($\sim100$ Myr) timescales. To estimate $η$, we apply the detailed time-luminosity relationship for H$α$ and near-ultraviolet emission to simulated star formation histories (SFHs) from semi-analytic models and the Mufasa hydrodynamical cosmological simulations. The average of $η$ is not a good indicator of star formation stochasticity (burstiness); indeed, we show that this average should be close to zero unless the population has an average SFH which is rising or falling rapidly. Instead, the width of the $η$ distribution characterizes the burstiness of a galaxy population's recent star formation. We find this width to be robust to variations in stellar initial mass function and metallicity. We apply realistic noise and selection effects to the models to generate mock HST and JWST galaxy catalogs and compare these catalogs with 3D-HST observations of 956 galaxies at $0.65<z<1.5$ detected in H$α$. Measurements of $η$ are unaffected by dust measurement errors under the assumption that $E(B-V)_\mathrm{stars}=0.44\,E(B-V)_\mathrm{gas}$ (i.e., $Q_\mathrm{sg}=0.44$). However, setting $Q_\mathrm{sg}=0.8^{+0.1}_{-0.2}$ removes an unexpected dependence of the average value of $η$ upon dust attenuation and stellar mass in the 3D-HST sample while also resolving disagreements in the distribution of star formation rates. However, even varying the dust law cannot resolve all discrepancies between the simulated and the observed galaxies.
HETDEX: Star Formation Stochasticity Diagram of Lyman Alpha Emitting Galaxies at Cosmic Noon Confirms Three Archetypes
Rutgers, the State University of New Jersey（新泽西州立罗格斯大学）；School of Natural Sciences, Institute for Advanced Study（高等研究院自然科学学院）；Columbia University（哥伦比亚大学）；New York City College of Technology（纽约市立技术学院）；University of Maryland Baltimore County（马里兰大学巴尔的摩县分校）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）；Center for Research and Exploration in Space Science and Technology, NASA/GSFC（NASA/GSFC空间科学与探索技术中心）；Purdue University（普渡大学）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；The Pennsylvania State University（宾夕法尼亚州立大学）
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）
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
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）
SkyMapper SEDs of nearby galaxies: quenching and bursting probed by a change index for star formation
天文学家的愿望清单包括一个工具，可以直接揭示星系中恒星形成过程的淬灭。在这里，我们提出了一个新的猝灭和爆发诊断，恒星形成的“变化指数”，只需要光度数据的概念验证，只要他们包括过滤器，如紫色$uv$带SkyMapper使用。该指数主要响应于恒星形成率的变化在20至500万年的时间尺度上，几乎是不敏感的尘埃灭绝。它有效地工作在100到150 Mpc的距离。我们探讨其应用SkyMapper DR 2中的8个示例星系，包括已知的E+A和Seyfert-1星系。由于宽带测光固有的简并性，变化指数只能是恒星形成率变化的定性指标。但是，一旦SkyMapper南方巡天完成，变化指数将可用于其工作距离范围内南方天空中每个星系的每个空间分辨率元素。
