We use our state-of-the-art Galaxy Evolution and Assembly (GAEA) semi-analytic model to study how and on which time-scales star formation is suppressed in satellite galaxies. Our fiducial stellar feedback model, implementing strong stellar driven outflows, reproduces relatively well the variations of passive fractions as a function of galaxy stellar mass and halo mass measured in the local Universe, as well as the `quenching' time-scales inferred from the data. We show that the same level of agreement can be obtained by using an alternative stellar feedback scheme featuring lower ejection rates at high redshift, and modifying the treatment for hot gas stripping. This scheme over-predicts the number densities of low to intermediate mass galaxies. In addition, a good agreement with the observed passive fractions can be obtained only by assuming that cooling can continue on satellites, at the rate predicted considering halo properties at infall, even after their parent dark matter substructure is stripped below the resolution of the simulation. For our fiducial model, the better agreement with the observed passive fractions can be ascribed to: (i) a larger cold gas fraction of satellites at the time of accretion, and (ii) a lower rate of gas reheating by supernovae explosions and stellar winds with respect to previous versions of our model. Our results suggest that the abundance of passive galaxies with stellar mass larger than ~10^10 Msun is primarily determined by the self-regulation between star formation and stellar feedback, with environmental processes playing a more marginal role.
Igniting Galaxy Formation in the Postreionization Universe, II: Nature versus Nurture
Pomona College（波莫纳学院）；Carnegie Observatories（卡内基观测站）；University of Southern California（南加州大学）；Indiana University（印第安纳大学）；California State Polytechnic University, Pomona（加州州立理工大学波莫纳分校）；California State University, San Bernardino（加州州立大学圣贝纳迪诺分校）；Universität Zürich（苏黎世大学）
Implications for the origin of dwarf early-type galaxies: a detailed look at the isolated rotating dwarf early-type galaxy CG 611, with ramifications for the Fundamental Plane's (S_K)^2 kinematic scaling and the spin-ellipticity diagram
Probing the role of the galactic environment in the formation of stellar clusters; using M83 as a test bench
我们提出了一个研究的M83集群人口，覆盖盘的星系半径之间的0.45和4.5千秒差距。我们的目标是探索集群人口的属性作为一个函数的距离银河系中心。我们观察到星系团形成效率（$Γ$，即在束缚星系团中发生的恒星形成量）的净下降，从内部区域的26%下降到星系外部的8%。恢复的$Γ$值在不同地区的M83遵循相同的$Γ$与恒星形成率密度关系观察整个星系。我们还探讨了初始集群质量函数（ICMF）作为银河距离的函数。我们观察到一个显着的陡峭的ICMF在外部地区（从$-1.90\pm0.11$到$-2.70\pm0.14$）和整个星系团人口（斜率$-2.18\pm0.07$）的M83。我们表明，这种变化的斜率反映了一个更根本的变化的“截断质量”的高质量端的分布。这可以模拟为斜率$-2$的Schechter函数，其指数截止质量（$M_{\rm c}$）从内部到外部区域显著减小（从4.00到$0.25\times 10^5$ M $_\odot$），而银河系的$M_{\rm c}$为$\approx1.60\times10^5$ M $_\odot$。Γ和ICMF的趋势与观测到的$Σ({\rm H}_2)$径向减小一致，因此与气体压力一致。随着气体压力下降，团簇形成的效率降低。我们得出结论，宿主星系环境似乎调节1）锁定在星团中的恒星比例; 2）ICMF的质量上限，一致地由在高质量端截断的接近普遍的斜率$…
The driving mode of turbulence in disc galaxy simulations with adaptive mesh refinement
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）；Lund Observatory, Division of Astrophysics, Department of Physics, Lund University（隆德大学物理系天体物理学部隆德天文台）
